EP2676737A1 - Drawback check valve - Google Patents
Drawback check valve Download PDFInfo
- Publication number
- EP2676737A1 EP2676737A1 EP13172419.7A EP13172419A EP2676737A1 EP 2676737 A1 EP2676737 A1 EP 2676737A1 EP 13172419 A EP13172419 A EP 13172419A EP 2676737 A1 EP2676737 A1 EP 2676737A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- spring
- tube
- edge portion
- piston head
- axially
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47K—SANITARY EQUIPMENT NOT OTHERWISE PROVIDED FOR; TOILET ACCESSORIES
- A47K5/00—Holders or dispensers for soap, toothpaste, or the like
- A47K5/06—Dispensers for soap
- A47K5/12—Dispensers for soap for liquid or pasty soap
- A47K5/1202—Dispensers for soap for liquid or pasty soap dispensing dosed volume
- A47K5/1204—Dispensers for soap for liquid or pasty soap dispensing dosed volume by means of a rigid dispensing chamber and pistons
- A47K5/1205—Dispensing from the top of the dispenser with a vertical piston
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B11/00—Single-unit hand-held apparatus in which flow of contents is produced by the muscular force of the operator at the moment of use
- B05B11/0005—Components or details
- B05B11/0062—Outlet valves actuated by the pressure of the fluid to be sprayed
- B05B11/007—Outlet valves actuated by the pressure of the fluid to be sprayed being opened by deformation of a sealing element made of resiliently deformable material, e.g. flaps, skirts, duck-bill valves
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B11/00—Single-unit hand-held apparatus in which flow of contents is produced by the muscular force of the operator at the moment of use
- B05B11/01—Single-unit hand-held apparatus in which flow of contents is produced by the muscular force of the operator at the moment of use characterised by the means producing the flow
- B05B11/10—Pump arrangements for transferring the contents from the container to a pump chamber by a sucking effect and forcing the contents out through the dispensing nozzle
- B05B11/1001—Piston pumps
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B11/00—Single-unit hand-held apparatus in which flow of contents is produced by the muscular force of the operator at the moment of use
- B05B11/01—Single-unit hand-held apparatus in which flow of contents is produced by the muscular force of the operator at the moment of use characterised by the means producing the flow
- B05B11/10—Pump arrangements for transferring the contents from the container to a pump chamber by a sucking effect and forcing the contents out through the dispensing nozzle
- B05B11/1097—Pump arrangements for transferring the contents from the container to a pump chamber by a sucking effect and forcing the contents out through the dispensing nozzle with means for sucking back the liquid or other fluent material in the nozzle after a dispensing stroke
Definitions
- This invention also relates generally to a piston for a pump and, more particularly, to an arrangement for a disposable variable length piston for piston pumps for dispensing flowable materials.
- dispensers of material such as creams and for example liquid honey have the problem of stringing in which an elongate string of fluid hangs from fluid in the outlet and dangles from the outlet after dispensing an allotment of fluid. With passage of time the string may form into a droplet and drop from the outlet giving the appearance that the dispenser is leaking.
- the present invention is particularly applicable to fluid dispensers which fluid is to be dispensed out of an outlet with the outlet forming an open end of a tubular member.
- the tubular member has its outlet opening downwardly and fluid passing through the tubular member is drawn downwardly by the forces of gravity.
- An object of the second aspect of the present invention is to provide a fluid dispenser in which after dispensing fluid out an outlet draws fluid back through the outlet to reduce dripping and/or stringing.
- valve member comprising a spring member and a piston head member
- the spring first end coupled to the tube inner wall at a first location against relative axial movement with the tube member
- the piston-forming element having an inner head portion, an outer base portion and a variable length portion intermediate the head portion and the base portion joining the head portion and the base portion,
- the base portion having a central axially extending hollow stem having a central passageway open at an outer end forming an outlet
- Figure 15 is a pictorial view similar to Figure 5 but of a second embodiment of a valve piston member adapted for substitution for the valve piston member in Figure 5 and showing the valve piston member in an uncompressed condition;
- Figure 17 is a cross-sectional end view similar to Figure 6 but of the valve piston member of Figure 15 along section line A-A' in Figure 15 ;
- Figure 18 is a cross-sectional side view similar to Figure 2 but of a third embodiment of a piston pump adapted for substitution for the pump piston in Figure 1 and with the valve piston member in an uncompressed condition;
- Figure 20 is a cross-sectional side view similar to Figure 2 but of a fifth embodiment of a pump piston adapted for substitution for the pump piston in Figure 1 and with the valve piston member in an uncompressed condition;
- Figure 21 is a cross-sectional view similar to Figure 18 of a sixth embodiment of a pump piston for use in substitution of the pump piston in Figure 1 ;
- Figure 22 is a cross-sectional view of a pump in accordance with the seventh embodiment of the invention with the pump piston in an extended position and a valve piston member in an uncompressed condition;
- Figure 24 is a cross-sectional side view of the pump piston as in Figure 22 but with the valve piston member in a first compressed condition;
- Figure 26 is a cross-sectional side view of an eighth embodiment of a pump piston for use in the pump shown in Figure 22 with a valve piston member in an uncompressed condition;
- Figure 28 is a cross-sectional side view of a tenth embodiment of a pump piston for use in the pump shown in Figure 22 with a valve piston member in an uncompressed condition;
- Figure 32 is a cross-sectional side view of a thirteenth embodiment of a pump piston for use in the pump shown in Figure 22 with a valve piston member in an uncompressed condition;
- Figure 33 is a cross-sectional side view of a fourteenth embodiment of a pump piston for use in the pump shown in Figure 22 with a valve piston member in an uncompressed condition;
- Figure 35 is a side view showing a portion of Figure 34 enlarged
- Figure 36 is an enlarged side view similar to that shown in Figure 35 but showing a sixteenth embodiment of a pump piston of the present invention
- Figure 37 is a side view the same as in an unbiased condition in Figure 36 with the pump piston in a biased condition;
- Figure 40 is a schematic side view of a portion of a fluid dispenser in accordance with an eighteenth embodiment of the present invention having similarities to the embodiment shown in Figure 39 ;
- Figure 42 is a perspective view of a valve piston member in accordance with a nineteenth embodiment of the present invention.
- Figure 44 is a pictorial view of a piston valve member in accordance with a twenty-first embodiment of the present invention.
- Figure 45 is a schematic side view of a portion of a fluid dispenser in accordance with a twenty-second embodiment of the present invention having similarities to the embodiment shown in Figure 40 ;
- Figure 47 is a schematic side view of a portion of a fluid dispenser in accordance with a twenty-third embodiment of the present invention having similarities to the embodiment shown in Figure 40 .
- FIG. 1 comprising a pump assembly 10 secured to a reservoir or container 26 having a threaded neck 34.
- the pump assembly has a body 12, a one-way valve 14 and a pump piston 16.
- the body 12 provides a cylindrical chamber 18 in which the pump piston 16 is axially reciprocally slidable in a cycle of operation so as to draw fluid from within the container 26 and dispense it out of an outlet 54.
- the chamber 18 has a cylindrical chamber wall 20 disposed coaxially about a central chamber axis 22.
- the head portion 47 includes a centrally extending head stem 30 upon which a head disc 48 is mounted.
- the head disc 48 extends radially outwardly from the head stem 30 as a circular resilient flexible disc located at the inwardmost end of the head portion 47 and extending radially therefrom.
- the head disc 48 is sized to circumferentially abut the inner chamber wall 20 substantially preventing fluid flow therepast inwardly in the chamber 18.
- the head disc 48 is formed as a thin resilient disc having an elastically deformable edge portion 48a to engage the chamber wall 20.
- the edge portion extends radially outwardly and in a direction axially outwardly of the chamber 18.
- the edge portion is adapted to deflect radially inwardly away from the chamber wall 20 to permit fluid flow outwardly in the chamber 18 therepast.
- the head stem 30 has a center 33 coaxial about the axis from which four elongate arms 32 extend radially outwardly and axially to provide an X shape in cross-section as in Figures 6 and 8 .
- Each arm 32 carries at its axial end a radially outwardly extending hooking member 34 with an axially inwardly directed catching surface 35.
- the variable length intermediate portion 45 comprises an elongate tubular member 200 disposed to bridge between the head portion 47 and the base portion 49 joining them together axially spaced apart.
- the tubular member 200 has an inner end 202 and an outer end 204.
- the inner end 202 of the tubular member 200 is fixedly coupled to the head portion 47 by being formed integrally therewith.
- the outer end 204 of the tubular member 200 engages the base portion 49.
- the tubular member 200 is coupled to the head portion 47 and the base portion 49 in a manner so as to not interfere with the engagement of the head disc 48 and a base disc 50 carried on the base portion 49 with the side wall 20 of the chamber.
- the tubular member 200 has a wall 206 extending between the inner end 202 and the outer end 204.
- the wall 206 has a radially inwardly directed inner wall surface 208 and a radially outwardly directed outer wall surface 210.
- the wall 206 has the shape of a solid of revolution rotated about the central axis 22.
- the wall extends circumferentially entirely about the central axis 22, that is, 360 degrees about the central axis 22.
- Each of the inner end 202 and the outer end 204 is an annular ring that extends annularly 360 degrees about the central axis 22.
- a plurality of openings 212 extend radially through the wall 206 between the inner wall surface 208 and the outer wall surface 210.
- the openings 212 each have an axial extent.
- the openings 212 are spaced circumferentially about the tubular member 200 with each openings 212 spaced circumferentially from its adjacent openings 212 by an axially extending web 213.
- the openings 212 are identical and evenly spaced circumferentially by identical webs 213.
- Each opening 212 is shown to be defined between an inner end surface 501, an outer end surface 503 and two side surfaces 505 and 507.
- Each opening 212 is axially elongate and has an axial extent between the inner end surface 501 and the outer end surface 503.
- Each opening has a circumferential extent between the side surfaces 505 and 507.
- the valve body or base portion 49 has a base stem 46 that carries the base disc 50, locating disc 66, locating webs 67 and an engagement flange 62.
- the base disc 50 is a circular resilient flexible disc located on the stem 46 spaced axially outwardly from the head disc 48.
- the base disc 50 extends radially outwardly from the stem 46 to circumferentially engage the chamber wall 20 substantially preventing fluid flow therebetween outwardly in the chamber 18.
- the base disc 50 is preferably formed as thin resilient disc, in effect, having an elastically deformable edge portion 30a to engage the chamber wall 20.
- the stem 46 has a central passageway 52 extending along the axis 22 from an inner inlet end 58 located on the stem 46 between the head disc 48 and the base disc 50 to the outlet 54 at the outer end of the base portion 49.
- the passageway 52 permits fluid communication through the base portion 49 past the base disc 50, between the inlet end 58 and the outlet 54.
- Locating discs 66 and locating webs 67 best seen in Figure 7 are provided to engage the chamber wall 20 so as to assist in maintaining the base portion 49 axially centered within the chamber 18 when sliding axially in and out of the chamber 18.
- the stem 46 comprises a tubular member and can be seen to have the passageway 52 extend therethrough between the outlet 54 and the inlet end 58 with the inlet end 58 open to the chamber 18 between the head disc 48 and the base disc 50.
- Each of the base portion 49 and the head portion 47 is circular in any in cross-section normal the axis 22 therethrough.
- Each of the base portion 49 and the head portion 47 is adapted to be slidably received in chamber 18 coaxially within the chamber 18.
- the passageway 52 has its side wall 52a formed to provide an axially outwardly directed catch surface 290 which forms a hook member in axial opposition to the axially inwardly directed catching surface 35 to be engaged by the hooking member 34 of the head stem 30 and limit inward axial movement of the head portion 47 relative the base portion 49.
- the catch surface 290 is provided as an axially outwardly directed shoulder between an inner portion of the passageway 52 of a first diameter and an outer portion of a larger diameter.
- the engagement flange 62 is provided on the stem 46 for engagement as by an actuator, not shown, to move the base portion 49 inwardly and outwardly.
- the engagement flange 62 may also serve the function of a stopping disc to limit axial inward movement of the pump piston 16 by engagement with the outer end 23 of the body 12.
- the stem 46 is shown to extend outwardly from the engagement flange 62 to the discharge outlet 54 as a relatively narrow hollow tube 138 with the passageway 52 coaxially therethrough.
- the one-way valve 14 comprises a unitary piece of resilient material having a resilient, flexible, annular rim 132 for engagement with the side wall of the chamber 18.
- the one-way valve 14 is integrally formed with a shouldering button 134 which is secured in a snap-fit inside an opening 136 in a central upper end of the chamber 18.
- annular inner compartment 111 is formed inside the chamber 18 between the one-way valve 14 and the head disc 48 and an annular outer compartment 112 is formed inside the chamber 18 between the head disc 48 and the base disc 50.
- the volume of the annular outer compartment 112 varies with variance of the axial length of the variable length intermediate portion 45 of the pump piston 16.
- the body 12 carries an outer cylindrical portion 40 carrying threads 130 to cooperate with threads formed on the threaded neck 34 of the container 26.
- the pump assembly 10 is preferably orientated such that such that the outlet 54 is directed downwardly, however, this is not necessary.
- the tubular member 200 has an inherent resiliency by reason of being formed from a suitable resilient material, preferably plastic material.
- the inherent resiliency of the tubular member 200 biases the tubular member 200 to adopt an unbiased configuration of a maximum axial length measured along the central axis.
- the tubular member 200 is subjected to axially directed compression forces the tubular member 200 compresses axially such that its axial length as measured along the central axis 22 reduces and when such compressive forces are released, the tubular member 200 increases in length expanding towards the unbiased condition.
- Figure 2 shows the pump piston 16 and its valve piston member 15 in an uncompressed condition.
- Figure 3 shows the pump piston 16 and its valve piston member 15 in a first compressed condition in which the variable length intermediate portion 45 and its tubular member 30 are compressed to be of reduced axial length compared to Figure 2.
- Figure 4 shows the pump piston 16 and its valve piston member 15 in a second compressed condition compressed to be of reduced axial length compared to Figure 3 .
- the tubular member 200 is disposed about the central axis 22 bridging between the head portion 47 and the base portion 49 and acts in the manner of a spring to urge the head portion 47 and base portion 49 axially apart.
- the inner end 202 of the tubular member 200 is fixed to the head stem 30 radially inwardly from the head disc 48 by being formed integrally therewith.
- the base portion 49 is arranged such that the outer end 204 of the tubular member 200 engages the base stem 46 of the base portion 49 radially inwardly from the base disc 50.
- the base portion 49 provides an axially inwardly directed surface 300 at its inner end between the inner inlet end 58 of the passageway 52 and the base disc 50 which surface 300 is to be engaged by the outer end 204 of the tubular member 200.
- an annular groove 301 is provided in the surface 300 open axially inwardly within which groove 301 the outer end 204 of the tubular member 200 is seated. Engagement between the annular groove 301 and the outer end 204 of the tubular member 200 assists in maintaining the tubular member 200 coaxially disposed about the central axis 22.
- the groove 301 preferably has an outer side surface which is directed radially inwardly to engage the outer surface 210 of the wall of the tubular member 200.
- the variable length intermediate portion 45 has an axial length defined as a length measured along the central axis 22 as between the head disc 48 and the base disc 50. This axial length is measured along the axis 22 between a center 218 on the head portion 47 and a center 220 of the base disc 50.
- the axial length is indicated as L on Figure 2 and is variable between a maximum length and a minimum length due to the ability of the elongate members 200 to deflect.
- the pump assembly 10 is shown in Figures 12 , 13 and 14 in use in a cycle of operation of the pump.
- Figures 11 and 14 show the pump piston 16 within the chamber 18 of the body 12 in an uncompressed condition (also sometimes referred to herein as an expanded condition) as seen in Figure 2 in which the variable length intermediate portion 45 is in its maximum length.
- an uncompressed condition also sometimes referred to herein as an expanded condition
- resistance to movement of the head portion 47 and particularly its head disc 48 within the chamber 18 will give rise to tension forces being applied across the tubular member 200.
- the response of the tubular member 200 to such tension force will depend upon the nature and resiliency of the tubular member 200 and the amount of the tension force.
- Figures 12 and 13 show the pump piston 16 received in the chamber 18 of the body 12 with the variable length intermediate portion 45 in a first compressed condition as seen in Figure 3 .
- the base portion 49 inwardly in the chamber 18 resistance to inward movement of the head portion 47 and notably resistance to movement of the head disc 48 inwardly in the chamber 18 results in compressive forces being applied to the variable length intermediate portion 45 between the base portion 49 and the head portion 47.
- Such compressive forces cause the tubular member 200 to deform to reduce the axial length of the variable length intermediate portion 45 to a reduced length compressed condition as seen in Figures 12 and 13 .
- variable length intermediate portion 45 In operation of the pump, the relative tension forces and compression forces which may be applied through the variable length intermediate portion 45 between the base portion 49 and the head portion 47 will cause the variable length intermediate portion 45 to adopt configurations between an expanded condition and a compressed condition.
- the relative resistance of the head portion 47 to sliding within the chamber 18 is affected by many factors including the friction to movement of the head portion 47 within the chamber 18, inwardly and outwardly, the nature of the fluid in the reservoir having regard to, for example, its viscosity and temperature, the speed with which the base portion 49 is moved and various other factors which will be apparent to a person skilled in the art.
- a person skilled in the art by simple experimentation can determine suitable configurations for the intermediate member 45 so as to provide for the axial length of the variable length portion to vary between a suitable minimum length and a suitable maximum length in cyclical movement of the pump piston 16 in a cycle of operation.
- the outer wall surface 210 of the wall 206 of the tubular member 200 as seen in side view in Figure 2 in the uncompressed condition is convex, that is, the outer wall surface 210 bows radially outwardly.
- the openings 212 are provided through the wall 206 such that the openings change in relative shape with axial deflection of the tubular member 200.
- Each opening 212 provides a passage through which fluid may flow through the wall 206.
- each opening 12 provides a minimum cross-sectional area for fluid flow therebetween.
- the cross-sectional area of the passage through openings 212 for fluid flow therethrough preferably increases as the tubular member 200 is deflected axially from the expanded condition to the compressed condition by reason of the circumferential extent of each opening between the side surfaces 505 and 507 increasing as the wall 206 bows out and the outer wall surface 210 increases in convexity. While not necessary, having the cross-sectional area of the passage through each opening increase as the tubular member 200 is compressed is advantageous since during operation of the pump, a larger volumetric fluid flow through the tubular member 200 is required when the tubular member 200 is compressed.
- Figure 6 shows a cross-sectional end view through the pump piston 16 in the uncompressed condition of Figure 2 in which the openings 212 are shown in end cross-section disposed between the webs 213.
- Figure 10 shows a similar cross-sectional end view as in Figure 6 , however, with the pump piston 16 in a compressed condition of Figure 3 in which the tubular member 200 is axially compressed compared to Figure 2 .
- each opening 212 has been increased by reason that side surfaces 505 and 507 defining each opening 212 are circumferentially farther apart in Figure 10 than in Figure 6 .
- the cross-sectional area for fluid flow through each opening is a function of the circumferential extent of the opening. Generally, in the first embodiment with an increase in circumferential extent, the cross-sectional area of the opening increases.
- the pump assembly operates in a cycle of operation in which the pump piston 16 is reciprocally moved relative the body 12 inwardly in a retraction stroke and outwardly in a withdrawal stroke.
- the withdrawal of the pump piston 16 causes the one-way valve 14 to open with fluid to flow past annular rim 132 which is deflected radially inwardly into the inner compartment 111 in the chamber 18.
- head disc 48 remains substantially undeflected and assists in creating a vacuum in the inner compartment 111 to deflect rim 132 and draw fluid past rim 132.
- the head disc 48 substantially prevents flow inwardly therepast in the withdrawal stroke and, on the other hand, deforms to permit flow outwardly therepast in the retraction stroke.
- the head disc 48 shown facilitates this by being formed as a thin resilient disc, in effect, having an elastically deformable edge portion near chamber wall 20.
- head disc 48 When not deformed, head disc 48 abuts the chamber wall 20 to form a substantially fluid impermeable seal.
- Head disc 48 When deformed, as by its edge portion 48a being bent away from wall 20, fluid may flow outwardly past the head disc, Head disc 48 is deformed when the pressure differential across it, that is, when the pressure on the upstream side is greater in the inner compartment 111 than the pressure on the downstream side in the outer compartment 112 by an amount greater than the maximum pressure differential which the edge portion of the head disc can withstand without deflecting.
- this pressure differential is sufficiently large, the edge portion of the head disc deforms and fluid flows outwardly therepast.
- the pressure differential reduces to less than a given pressure differential, the head disc 48 returns to its original inherent shape substantially forming a seal with the wall 20.
- Figures 11 to 14 show different conditions the variable length intermediate portion 45 assumes in a cycle of operation.
- the base portion 49 is moved in a retraction stroke from an extended position as seen in Figure 11 to a retracted position as seen in Figure 13 .
- a withdrawal stroke the base portion 49 is moved from the retracted position of Figure 13 to the extended position shown in Figure 11 .
- Figure 11 illustrates the pump piston 16 with the base portion 49 in the extended position and the pump piston 16 and its valve piston member 15 and its variable length intermediate portion 45 in an uncompressed condition.
- the outer compartment 112 formed in the chamber 18 between the head disc 48 and base disc 49 is at a maximum volume.
- the base portion 49 is moved inwardly in a retraction stroke to assume the condition of Figure 12 in which the pump piston 16, its valve piston member 15 and its variable length intermediate portion 45 are a compressed condition.
- variable length intermediate portion 45 On the base portion 49 moving inwardly in the chamber 18 from the position of Figure 11 , while the length of the variable length intermediate portion 45 is greater than its minimum length, resistance to movement of the head portion 47 and its head disc 48 inwardly in the chamber 18 is sufficient that the length of the variable length intermediate portion 45 decreases toward its minimum length as shown in Figure 12 before the head portion 47 is moved inwardly in the chamber 18.
- compressive forces will be applied to the variable length intermediate portion 45 which forces will reduce the length of the variable length intermediate portion 45 until the compressive forces transferred by the variable length intermediate portion 45 are greater than the resistance to movement of the head portion 47 inwardly in the chamber.
- the compressive forces may be developed such that the variable length intermediate portion substantially decreases to its minimum length before the head portion 47 is substantially moved inwardly.
- tension forces will act on the variable length intermediate portion 45 expanding the variable length portion 45 until such time as the tension forces which are transferred by the variable length intermediate portion 45 from the base portion 49 the head portion 47 are greater than the resistance of the head portion for movement outwardly in the chamber.
- the tension forces may be developed such that the variable length intermediate portion 45 substantially increases to its maximum length before the head portion 47 is substantially moved outwardly.
- variable length intermediate portion 45 is maintained in the expanded condition with the variable length intermediate portion 45 at its maximum length and tension forces caused by movement of the base portion 49 are transferred via the variable length intermediate portion 45 to the head portion 47.
- the volume of the inner compartment 111 reduces and hence fluid is discharged from the inner compartment 111 past the head disc 48, through the tubular member 200 via the openings 212 through the passageway 52 out the outlet 54 since fluid within the chamber 18 is prevented from passing inwardly past the one way valve 14 and is prevented from passing outwardly past the base disc 50.
- pressure is created within the inner compartment 111 which closes the one-way valve 14. Fluid within the inner compartment 111 becomes compressed by movement of the head disc 48 inwardly.
- the relative nature of the head disc 48 and the base disc 50 and the engagement of each with the chamber wall 20 are preferably selected such that vacuum created within the outer compartment 112 will drawback fluid from the passageway 52 rather than deflect the head disc 48 to draw liquid from the inner compartment 111 past the head disc 48 into the outer compartment 112, or, deflect the base disc 50 to draw atmospheric air between the base disc 50 and the chamber wall 20.
- the drawback pump assembly 10 in accordance with the present invention may be used in manually operated dispensers such as those in which, for example, the pump piston 16 is moved manually as by a user engaging an actuator such as a lever which urges the pump piston 16 either outwardly or inwardly.
- the drawback pump can also be used in automated systems in which a user will activate an automated mechanism to move the pump piston 16 in a cycle of operation.
- a preferred arrangement for operation of the drawback pump assembly 10 in accordance with the present invention is for the pump assembly to assume a position between the condition shown in Figure 14 and the condition shown in Figure 11 as a rest position between cycles of operation.
- the dispenser may be arranged such that the base portion 49 is biased to assume as a rest position between cycles of operation, the extended position seen in Figure 11 .
- a person would manually operate a lever to move the dispenser from the position of Figure 11 to the position of Figure 13 .
- a spring will return the lever and base portion 48 to the position of Figure 11 .
- fluid is dispensed from the outlet 54.
- a rest position between cycles may preferably be at some point in between the position of Figure 14 and the position of Figure 11 .
- valve piston member 15 consisting of the piston head portion 47 and intermediate portion 45 as being formed from a unitary piece of plastic preferably by injection molding. It is to be appreciated that a similar structure could be formed with each of the head portion 47, base portion 49 and intermediate portion 45 being separately formed. Also the variable length intermediate portion 45 could be formed together with either or both of the head portion 47 and the base portion 49 as a unitary piece of plastic.
- the tubular member 200 has an inherent unbiased condition when molded.
- An assembled pump piston 16 will have an inherent unbiased condition as seen in Figure 2 which it will assume when no axial forces are applied to it.
- the inherent unbiased condition of the pump piston 16 depends on the inherent unbiased condition of the head portion 47, the base portion 49 and the intermediate portion 45. In the preferred embodiment, effectively only the tubular member 200 is axially deformable.
- the tubular member 200 is axially compressible from the inherent unbiased condition to assume conditions in which its axial length is reduced compared to the inherent unbiased condition. When deformed to a reduced length condition and released, the tubular member returns to its inherent unbiased condition.
- the tubular member can also be axially expandable from the inherent unbiased condition to a stretched position in which its axial length is increased compared to the inherent unbiased condition. For example, if the wall of the tubular member is in the inherent unbiased condition, not straight but bowed, then on applying axial tension forces, the wall may be deformed against its bias to become straight increasing the axial length.
- the tubular member 200 cannot be stretched and has its maximum axial length as the inherent unbiased condition.
- having the tubular member 200 compressed has the advantage that the inherent bias of the tubular member 200 will assist in ensuring that the outer end 204 of the tubular member 200 is maintained and urged into engagement with the groove 301.
- the tubular member 200 is selected so as to provide the head portion 47 and its head disc 48 maintained coaxially arranged within the chamber.
- Figure 1 illustrates a four-piece pump having as the four pieces, the body 12, the one-way valve 14 and the two-piece pump piston 16, and in which the chamber 18 in the body 12 has a constant diameter.
- the invention of the present application is also adaptable for use with two piece pumps having a stepped chamber. Such pumps have been disclosed in U.S. Patent 5,676,277 to Ophardt, issued October 14, 1997 , the disclosure of which is incorporated herein by reference.
- FIG. 15 to 17 showing a second embodiment in which a valve piston member 15 comprising a head portion 47 and a variable length intermediate tubular portion 45 is adapted for use with a base portion 49 identical to that shown, for example, in Figure 1 with the first embodiment.
- the only difference over the first embodiment of Figures 1 to 14 is the configuration of the openings 212.
- each of the side surfaces 507 and 509 which define the openings 212 therebetween converges at a common inner point 501 and at a common outer point 503.
- Figure 15 illustrates a condition in which the axial length of the tubular member 200 is greater than the axial length of the tubular member 200 in Figure 16 .
- each of the side surfaces 503 and 507 abut each other so as to close the openings 212 to prevent fluid flow therethrough.
- the concavity of the outer surface 210 of the tubular member 200 increases and the side surfaces 505 and 507 come to have the circumferential extent to which they are spaced increase such that the openings 212 become of increased cross-sectional area.
- a passage is formed through each opening 212 of a given cross-sectional area
- Figure 15 the cross-sectional through any passage is reduced to zero as best seen in Figure 17 in cross-section.
- the second embodiment illustrated in Figures 15 to 17 may be manufactured in a number of ways.
- the wall of the tubular member 200 could be made initially without any openings 212 therethrough, and thereafter axially extending slits may be cut through the wall at each place where an opening 212 is desired.
- Each slit that is cut preferably would extend in a flat plane which includes a central axis 22 and extends radially outwardly therefrom through the wall. Where the slits are cut in an unbiased condition of the tubular member 200, the openings 212 would be closed.
- Adopting the pump piston 16 with an arrangement in which the pump piston 16 is in an unbiased condition when the tubular member 200 is in an unbiased condition or a stretched condition would result in the openings being closed when the pump piston is in the unbiased condition.
- Figure 18 shows a fourth embodiment of a piston pump in accordance with the present invention.
- the fourth embodiment of Figure 18 is substantially identical to the first embodiment of Figure 2 with a first exception that the head stem 30 of the valve piston member 15 of the first embodiment has been removed and is replaced by a hooking member 34 carried on the annular outer end 204 of the tubular member 200.
- the hooking member 34 is arrow head shaped and has axially inwardly directed catching surfaces 35 which extend both radially outwardly on an outer prong 160 and radially inwardly on an inner prong 161.
- two hook members are provided as firstly an annular axially inwardly extending resilient finger member 164 with a distal end which extends radially inwardly to provide an axially outwardly directed catch surface to engage the catching surface 35 of the outer prong 160 and secondly an annular axially inwardly extending resilient finger member 166 with a distal end which extends radially outwardly to provide an axially outwardly directed catch surface to engage the catching surface 35 of the inner prong 161.
- Engagement between the hooking member 34 and the finger members 164 and 166 couples the tubular portion 200 of the valve piston member 15 to the base portion 49 in a snap fit relation against axial removal.
- the hooking member 34 has angled camming surfaces on each radially inward and radially outward side outwardly of the catching surfaces to urge the fingers 164 and 166 radially apart in insertion. While two fingers 164 and 166 are shown only one is necessary.
- the tubular member 200 is symmetrical about the central axis 22 such that with axial compression and expansion of the resilient tubular member 200, the tubular member has an inherent bias to maintain itself coaxially disposed about the central axis 22 which, particularly with the embodiment of Figure 18 , can avoid the need for other coaxial locating devices such as the head stem which in the other embodiments serves to assist in coaxially locating the head portion 47 coaxially slidable relative to the base portion 49.
- Figure 19 shows a fourth embodiment of a pump assembly 10 in cross-section which uses a pump piston 16 with a valve piston member 15 with a head portion 47 as in the second embodiment in Figures 15 to 17 in which the openings 212 through the tubular members 200 close.
- the outer end 204 of the tubular member 200 carries a hooking member 34 adapted to engage in a hook member carried on the base portion 49 at an inner end of the base portion annularly about the inner opening of the base passageway 52.
- valve piston member 15 and its head portion 47 continue to include a cross shaped head stem 30 similar to that shown in the first embodiment, however, which head stem 30 does not carry the hooking members 34.
- the pump piston 16 is illustrated as being within body 12 attached to a bottle 26 similar to that shown in Figure 1 attached to a bottle 26.
- a removable closure cap 170 is provided which engages the body 12 in a snap-fit relation as by a radially inwardly extending hook ring on the cap 170 engaging a radially outwardly extending hook ring about an outer end 23 of the chamber wall 20.
- the cap 170 engages the engagement flange 62 to stop the base portion 49 from movement outwardly.
- the cap 170 has a center post 171 which extends into the passageway 52 of the base stem 46 to engage an outer end of the head stem 30 in a position that maintains the tubular portion 200 with its opening 212 closed preventing fluid flow outwardly. Fluid flow outwardly can also be prevented by the center post 171 preventing flow out the outlet 54.
- the openings 212 of the tubular member 200 could be formed as by injection molding at the time of forming the tubular member 200. These openings 212 are to be closed on applying the cap 170 by the tubular member 200 being stretched by engagement of the center post 171 to have the axial length of the tubular member 200 increased from the inherent unbiased condition.
- the tubular member 200 could have the openings 212 open to provide fluid flow when the piston 16 is in an unbiased inherent condition.
- the cap urges the head stem 30 inwardly to increase the length of the tubular portion 200 and close the openings 212.
- FIG. 20 shows a fifth embodiment of the present invention.
- the fifth embodiment of Figure 20 is identical to the first embodiment of Figure 1 with the exception that the head stem 30 shown in the first embodiment to have an X-shape in cross-section is replaced by a tubular head stem 30 in the embodiment of Figure 20 .
- the tubular head stem 30 is formed with a cylindrical wall 150 and provides a head stem passageway 152 coaxial therethrough, closed at an inner end 151 and open at an outer end 153.
- a hooking member 34 is provided to extend radially outwardly from the exterior surface of the tubular head stem 30 and provide an axially inwardly directed catching surface 35 for engaging with the catch surface 290 on the base portion 49.
- One or more apertures 154 are provided through the wall 150 of the tubular head stem 30 to permit fluid flow from within the chamber 18 into the head stem passageway 152 through the tubular head stem 30 and hence into the base stem passageway 52 of the stem of the base portion to the outlet 54.
- Figure 21 shows a sixth embodiment of a piston pump in accordance with the present invention.
- the embodiment of Figure 21 is substantially the same as the embodiment illustrated in Figure 18 with the exception that the wall 206 of the tubular member 200 when compressed assumes an hourglass shape as seen in side in which the outer surface 210 of the wall is convex.
- the extent to which the outer surface 210 is convex increases as the axial length of the tubular member 200 decreases.
- the openings 212 through the tubular member 200 are to be provided such that they provide for flow as desired through the wall when the tubular member 200 is compressed.
- the openings 212 can have configurations which, when uncompressed, the openings are closed and, when compressed, the openings are open with increased cross-sectional area.
- a maximum reduction in the axial length of the tubular member 200 can be a configuration in which the inner surface 208 of the webs 213 on opposite sides of the tubular member 200 engage, or in versions in which a head stem 30 is provided, the inner surfaces 208 of the webs 213 engage the head stem.
- a limit on reduction of the axial length of the tubular portion 200 can be a position in which the outer surface 210 of the webs 213 extend radially outwardly to engage the wall 20 of the chamber 18.
- FIG. 1 illustrates the openings 212 through the wall 206 of the tubular member 200 as being identical openings evenly spaced circumferentially about the central axis 22. This is not necessary. Some openings 212 may be larger than other openings 212, however, a preferred configuration would be with openings 212 of comparable size symmetrically arranged relative to the central axis 22 to assist in maintaining the tubular member 200 coaxial about the central axis 22 with deflection.
- FIG. 22 shows a seventh embodiment of a piston pump assembly 10 in accordance with the present invention.
- the embodiment of Figure 22 has many similarities to the embodiment illustrated in Figure 1 and similar reference numerals are used to refer to similar elements.
- the pump piston 16 continues to be formed from two elements, namely, the valve piston member 15 and the valve body 17.
- the valve body 17 is modified over that shown in Figure 1 so as to have the central passageway 52 through the valve body 17 enlarged so as to provide a valve piston chamber 19 opening axially inwardly through the inlet end 58 and ending at an axially inwardly directed chamber shoulder 218.
- valve piston member 15 in Figure 22 is identical to that shown in Figure 5 , however, of reduced relative size compared to that shown in Figure 1 such that the head portion 47 and its head disc 48 are coaxially slidable within the valve piston chamber 19 with an edge portion of the head disc 48 to engage an inner cylindrical chamber wall 220 of the valve piston chamber 19 of the valve body 17 in Figure 22 in the same manner that in Figure 1 the edge portion of the head disc 48 engages the chamber wall 20 of the chamber 18 in the body 12.
- the outer end 204 of the tubular member 200 forming the intermediate portion 45 engages the chamber shoulder 218 of the valve body 17.
- valve piston member 15 in the embodiment of Figure 22 is substantially the same as is the case in the embodiment of Figure 1 with, however, the notable exception that the edge portion of the head disc 48 engages the chamber wall 220 of the valve body 17 rather than the chamber wall 20 of the body 12.
- a helical coil spring 222 is provided coaxially within the chamber 18 and adapted to bias the valve body 17 axially outwardly from the chamber 18 as by having an axial outer end 224 of the spring 222 engage the valve body 17 at an axially inwardly directed shoulder 226 on the valve body 17 radially outwardly of the opening to the valve piston chamber 19.
- An inner end 228 of the spring 222 is shown to engage a central non-deflecting portion of the one-way inlet valve 14.
- reference P1 identifies a pressure of fluid in the passageway 52 on an axial upstream side of the head disc 48 of the head portion 47 in the inner compartment 111 and reference P2 is a pressure of the fluid in the passageway 52 on an axial downstream side of the head disc 48 of the head portion 47 in the outer compartment 112.
- a pressure differential across the head disc 48 of the head portion 47 is measured as the upstream pressure P1 minus the downstream pressure P2.
- the tubular member 200 of the intermediate portion 45 acts as a spring member which is deflectable from an unbiased position as shown in Figure 23 to biased positions such as shown in Figures 24 and 25 with the tubular member 200 being resilient and having an inherent bias to assume the unbiased position in Figure 23 in which the tubular member 200 extends an axial distance equal to an unbiased length.
- the tubular member 200 is deflectable from the unbiased position of Figure 23 to biased positions such as shown in Figures 24 and 25 in which the length of the tubular member 200 is different than the unbiased length in Figure 23 .
- the tubular member 200 is deflectable from the unbiased position shown in Figure 23 to a first biased position shown in Figure 24 when the pressure differential across the head disc 48 is equal to a first pressure level.
- the peripheral circumferential edge portion 48a of the head disc 48 on the head portion 47 is elastically deformable between an unbiased condition and biased condition wherein in the unbiased condition, the edge portion engages the chamber wall 220 of the valve piston chamber 19 to prevent fluid flow therepast and in biased positions, the edge portion elastically deflects away from the chamber wall 220 to permit fluid flow therepast.
- the edge portion of the head disc 48 assumes it unbiased condition when the pressure differential across the head disc 48 is less than or equal to the first pressure level.
- the edge portion of the head disc 48 assumes biased conditions to permit fluid flow therepast when the pressure differential exceeds the first pressure level.
- Figure 23 illustrates a condition in which the pressure differential is less than the first pressure level.
- Figure 24 illustrates a condition in which the pressure differential is equal to the first pressure level and, as can be seen, the spring-forming tubular member 200 has been moved from an unbiased position as seen in Figure 23 to assume a biased condition in Figure 24 . In Figure 24 , however, the edge portion 48a of the head disc 48 continues to engage the chamber wall 220 to prevent fluid flow therebetween.
- Figure 25 illustrates a condition in which the pressure differential exceeds the first pressure level.
- the edge portion 48a of the head disc 48 has been deflected radially inwardly from the chamber wall 220 permitting fluid flow outwardly therepast.
- fluid may flow outwardly past the head disc 48 through the openings 212 of the tubular member 200 and out through the passageway 52 between the arms 32 of the head stem 30.
- head disc 48 reverts to an unbiased condition in which it prevents fluid flow outwardly therepast as the pressure differential drops to the first pressure level to adopt a position as shown in Figure 24 and, subsequently, with a further drop in the pressure differential to being less than or equal to the first pressure level, the spring forming tubular member 200 assuming an unbiased position as shown in Figure 23 .
- valve piston member 15 will move in a cycle from the position of Figure 23 to the position of Figure 24 to the position of Figure 25 , returning to the position of Figure 24 and subsequently returning to the position of Figure 23 .
- Figure 26 shows a pump piston 16 in accordance with an eighth embodiment of the present invention which is identical to that illustrated in Figure 23 with the exception that the valve piston chamber 19 has a chamber wall 220 which is stepped rather than being merely cylindrical as illustrated in Figure 23 .
- the chamber wall 220 includes an axially inner portion 230 of a first diameter, an axially outer portion 232 of a second diameter joined by an intermediate transition portion 231 which is shown to be frustoconical.
- Figure 27 shows a ninth embodiment of a pump piston 16 identical to that shown in Figure 26 but for the modification of the chamber wall 220 to show the transition portion 231 as being formed as a radially extending axially outwardly directed shoulder, and to replace the head disc 48, as seen in Figure 26 , with a modified head disc 48 having a substantially increased axial dimension such that the head disc 48, as shown in Figure 27 , has significantly reduced tendencies to have its edge portion deflect out of engagement with the chamber wall 220 over the inner portion 230.
- FIGS 28 and 29 show a tenth embodiment of a pump piston 16 in accordance with the present invention which has considerable similarities to the embodiment illustrated in Figure 23 .
- the tubular member 200 has been eliminated and replaced by a helical coil spring 334 which has an outer end 335 engaging the chamber shoulder 226 and an inner end 336 engage an axially outwardly directed surface 337 of the head portion 47 such that the spring 334 biases the head portion 47 axially inwardly to a position axially limited by the hooking member 34 engaging the outwardly directed catch surface 290.
- the relative resiliency of the spring 334 and the edge portion of the head disc 48 can be selected so as to permit the operation of the embodiment of Figure 28 to be the same as the embodiment of Figure 22 .
- Figure 28 also shows an optional modification of the chamber wall 220 so as to provide three circumferentially spaced axially extending radially inwardly directed spacing ribs 240 disposed in the outer portion 232 of the valve piston chamber 19.
- the deflection of the edge portion 48a of the head disc 48 radially inwardly to permit fluid flow therepast is provided by either or both of (1) the resilient deflection of the edge portion due to the increased pressure differential there across, and (2) the edge portion 48a of the head disc 48 on moving axially engaging the spacing ribs 240 which deflect the edge portion of the head disc 48 away from the chamber wall 220 permitting fluid flow therepast.
- the spacing ribs 240 can best be seen in the cross-section through the valve body 17 as seen in Figure 29 .
- the spacing ribs 240 are spaced axially outwardly from the location of the head disc 48 in the position as shown in Figure 28 such that the head disc 48 can be moved axially inwardly of the spacing ribs 240 for an axial distance in engagement with the chamber 220 which provides for suitable fluid drawback in operation.
- valve piston member 15 has included a spring-forming component 200 or 334 which is axially compressed to reduce an axial length as the pressure differential increases.
- valve piston member 15 includes a spring-forming component which is axially stretched to increase in axial length as the pressure differential increases.
- FIG. 30 illustrates a pump piston 16 in accordance with an eleventh embodiment of the present invention having considerable similarities to the pump piston shown in Figure 23
- the valve piston member 15 is modified over the valve piston member 15 shown in Figure 23 so as to conceptually remove the tubular member 200 from its position as illustrated in Figure 23 and locate the tubular member 200 such that it extends axially inwardly from the head portion 47 to a distal end carrying the radially outwardly extending hook members 34 to engage on the axially inwardly directed shoulder 226 at the axial inner end 224 of the valve piston chamber 19.
- the tubular member 200 is shown to be the same as in Figure 5 but inverted and secured to an inner end of the head portion 47.
- Figure 30 shows the tubular member 200 in an unbiased condition.
- the resilient spring forming tubular member 200 is expanded and the head portion 47 is thus moved axially inwardly until the pressure differential is increased sufficiently that the edge portion of the head disc 48 deflects from the chamber wall 220 permitting fluid flow axially therepast.
- the tubular member 200 returns from a biased extended condition to an unbiased retracted position drawing the head portion 47 axially inwardly. Fluid flow is permitted axially through the tubular member 200 via its opening 212.
- Figure 31 shows a twelfth embodiment of a pump piston 16 in accordance with the present invention which is substantially the same as the embodiment illustrated in Figure 31 but for three notable exceptions.
- the chamber wall 220 has a stepped configuration with inner portion 230, transition portion 231 and outer portion 232 similar to that illustrated in Figure 26 rather than being merely cylindrical as in Figure 30 .
- the spring forming tubular member 200 has a side wall in the form of a relative S shape rather than merely being at shape as seen in Figure 30 .
- annular catch member 34 provided at the axialtv inner end of the tubular member 200 extends radially outwardly and then axially inwardly so as to provide an axially inwardly directed annular groove 242 adapted to receive the outer end 224 of the internal coil spring 222 as can be of assistance in maintaining the axially inner end 224 of the tubular member 200 coupled to the axially inner end shoulder 226 of the valve body 17.
- FIG. 32 shows a thirteenth embodiment of a pump piston 16 in accordance with the present invention.
- the valve body 17 is illustrated as being formed from two elements, an axially outer portion 230 and an axially inner portion 232 which are secured together as in a snap-fit relation to jointly form the valve piston chamber 19 with the chamber wall 220 having a stepped configuration similar to that shown in Figure 31 .
- the inner portion 232 has a support plate 234 which extends across the axial inner end of the valve piston chamber 19 presenting openings 236 for fluid flow axially therethrough and also a central opening 238.
- the valve piston member 15 comprises a head portion 47 carrying a head disc 48 and a variable length intermediate portion 45.
- variable length intermediate portion 45 An axially outer end 240 of the variable length intermediate portion 45 is coupled to the head portion 47.
- the axially inner end 242 of the variable length intermediate portion 45 carries an enlarged catch button 244 with an axially outwardly directed catch surface 246 to engage the support plate 234 and prevent axial outward movement of the inner end 242 of the variable length intermediate portion 45.
- the intermediate portion 45 is resilient and adapted to elastically deform from an unbiased position as shown in Figure 32 to extend in axial length as the pressure differential across the head disc 48 increases and to return from biased positions to the unbiased position shown in Figure 32 .
- the intermediate portion 45 is stretched and expands to increase in axial length such that with sufficient pressure differential increase, the head portion 47 carrying the head disc 48 is moved axially outwardly until fluid is permitted to flow axially outwardly therepast as by the head disc 48 coming to become axially located in the enlarged diameter outer portion 232 of the chamber wall 220 and/or by radially inward deflection of the head disc 48,
- the valve piston member 15 includes a helical coil spring 250 as the variable length intermediate portion 45 which helical coil spring 250 biases the head portion 47 axially inwardly to an unbiased position.
- the coil spring has an axially outer end 251 engage an axially inwardly directed surface 252 of the support plate 234 and an axially inner end 254 engage an axially outwardly directed surface 256 of the catch button 244.
- the element forming the head portion 47 includes an inwardly extending stem 258 ending at the catch button 244. This head portion 47 need not have any substantial resiliency to axial deflection.
- FIGS 34 and 35 illustrate a fifteenth embodiment in accordance with the present invention adopting a configuration for the pump piston 16 having many similarities to that shown in the embodiment of Figure 22 , however, in which the valve body 17 is, as contrasted with the unitary element shown in Figure 22 , includes two elements, namely, a sealing member 740 and a valve seat member 742.
- the sealing member 740 carries the annular base disc 50.
- the sealing member 740 is adapted to sealably engage a discharge tube 716.
- the valve seat member 742 carries the check valve piston chamber 19 and the valve piston member 15 which are substantially identical to that illustrated in Figure 22 .
- a lower end of the tube 716 is frictionally and sealably received inside the cylindrical inner side wall 754 of the socket 744 abutting on the shoulder 756.
- the pump piston 16 comprises three elements, namely, a casing 832, the valve piston member 15 and the discharge tube 716.
- valve piston member Operation of the valve piston member is in the valve piston chamber 19 is the same as that described with reference to Figure 32 such that as the pressure differential across the head disc increases, the intermediate portion 45 is stretched and expands or increases in axial length such that with sufficient pressure differential, the head disc 48 is moved axially outwardly until fluid is permitted to flow axially therepast as by the head disc coming to become axially located in the larger diameter outer portion 232 of the chamber wall 220 and/or by radially inward deflection of the head disc 48.
- the casing and its discharge tube effectively forms the valve body 17 about the valve piston member 15.
- the head disc 48 when the pressure differential reduces, then the head disc 48 preferably to provide drawback will under its resiliency deflect radially outward into sealed engagement with the annular side wall of the valve body 17 to form a seal therewith before the length of the tubular portion 200 has increased to return the head disc 48 into engagement with the support plate 234.
- Figures 45 and 46 shows an embodiment identical to that in Figures 40 and 41 , respectively, however, in which the annular groove 858 between the head disc 48 and the tubular member 200 as seen in Figures 40 and 41 , has been eliminated such that the head disc 48 is solid and merges radially into the tubular member 200.
- the inherent resiliency of the material forming the head disc 48 can provide the desired deflection and inherent bias to the head disc 48.
- the resiliency of the head disc 48 can be adjusted either by increasing the relative size of the annular groove 858 in the embodiment of Figures 40 and 41 or by adjusting the resiliency of the material forming the valve piston member 15 as in the embodiment of Figures 45 and 46 .
- Figure 43 shows a thin member in accordance with a twentieth embodiment of the invention.
Abstract
Description
- This invention relates to a fluid dispenser which provides for drawback of fluid from a discharge opening and, more particularly, to a valve arrangement which effectively provides a one-way check valve other than under conditions in which a drawback of fluid dispensed is provided by the valve.
- This invention also relates generally to a piston for a pump and, more particularly, to an arrangement for a disposable variable length piston for piston pumps for dispensing flowable materials.
- Fluid dispensers are known incorporating fluid pumps in which an outer one-way check valve permits flow outwardly therepast in a downstream direction yet prevents fluid flow therepast inwardly in an upstream direction. Such known pump mechanisms include various dispensers for dispensing fluid drawn from the inside of a upstanding container for dispensing out a downwardly directed discharge outlet such as, for example, disclosed in
U.S. Patent 8,070,844, issued December 13, 2011 to Ophardt et al , the disclosure of which is incorporated herein by reference. - Such known liquid dispensers suffer the disadvantage that after use of the dispenser, while the dispenser is at rest, fluid may drip from the discharge outlet.
- Many dispensers of liquid such as hands soaps, creams, honey, ketchup and mustard and other viscous fluids which dispense fluid from a nozzle leave a drop of liquid at the end of the outlet. This can be a problem that the liquid may harden, as creating an obstruction which reduces the area for fluid flow in future dispensing. The obstruction can result in future dispensing through a small area orifice resulting in spraying in various directions such as onto a wall or user to stain the wall or user or more disadvantageously into the eyes of a user.
- Many dispensers of material such as creams and for example liquid honey have the problem of stringing in which an elongate string of fluid hangs from fluid in the outlet and dangles from the outlet after dispensing an allotment of fluid. With passage of time the string may form into a droplet and drop from the outlet giving the appearance that the dispenser is leaking.
- Pump assemblies for fluid dispensers are well known. Such pump assemblies includes those invented by the inventor of this present application including those disclosed in
U.S. Patent 5,165,577, issued November 24, 1992 ;U.S. Patent 5,282,552, issued February 1, 1994 ;U.S. Patent 5,676,277, issued October 14, 1997 ,U.S. Patent 5,975,360, issued November 2, 1999 , andU.S. Patent 7,267,251, issued September 11, 2007 , the disclosures of which are incorporated herein by reference. - Many previously known piston pumps suffer the disadvantage that the pistons for the pump are difficult to manufacture.
- To at least partially overcome some of the disadvantages of previously known devices, the present invention in a first aspect provides a valve for a pump arrangement which serves on one hand as a one-way outlet valve subject to functioning, after fluid has been dispensed, of drawing back some fluid which has been dispensed.
- To at least partially overcome some of the disadvantages of previously known devices, the present invention in a second aspect provides a piston pump having a piston and a piston chamber forming member in which the piston forms a compartment of variable axial length inside a piston chamber between a piston head portion of the piston and a piston base portion of the piston spaced axially from the piston head portion by reason of a resilient portion of the piston biasing the piston head portion and the piston base portion axially apart with the resilient portion preferably being tubular, preferably being disposed between the piston head portion and piston base portion, and preferably with openings radially through the tubular piston intermediate resilient portion for fluid flow therethrough.
- The present invention is particularly applicable to fluid dispensers which fluid is to be dispensed out of an outlet with the outlet forming an open end of a tubular member. In many applications, the tubular member has its outlet opening downwardly and fluid passing through the tubular member is drawn downwardly by the forces of gravity.
- An object of the first aspect of the present invention is to provide a novel one-way valve arrangement which also provides for drawback of fluid passed therethrough after fluid has been dispensed.
- An object of the second aspect of the present invention is to provide a fluid dispenser in which after dispensing fluid out an outlet draws fluid back through the outlet to reduce dripping and/or stringing.
- Another object of the present invention is to provide a simplified piston pump for dispensing fluid and after dispensing draws back fluid from the outlet of a nozzle from which the fluid has been dispensed.
- Another aspect is to provide a valving member which varies the extent to which fluid flow is permitted therethrough with axial deflection of a tubular wall.
- Accordingly, in accordance with the first aspect, the present invention provides, in combination, a tube member and a valve member:
- the tube member having a tube inner wall defining therein an axially extending fluid passageway for flow of a fluid in an axial downstream direction therethrough,
- the tube inner wall having a tube upstream portion and a tube downstream portion, the tube downstream portion located in the downstream direction from the tube upstream portion,
- the valve member disposed within the passageway,
- the valve member comprising a spring member and a piston head member,
- the spring member having a spring first end and a spring second end, the spring member extending axially within the passageway from the spring first end to the spring second end,
- the spring first end coupled to the tube inner wall at a first location against relative axial movement with the tube member,
- the piston head member fixedly secured to the spring second end,
- the spring member being resilient and having an inherent bias to assume an unbiased position in which the spring second end is axially spaced from the spring first end by a distance equal to an unbiased length,
- the spring member deflectable from the unbiased position to biased positions in which the spring second end is axially spaced from the spring first end by distances different than the unbiased length,
- in moving from the unbiased position to the biased positions the spring second end is moved in the axial downstream direction relative the spring first end,
- piston head member having an axial downstream side and an axial upstream side,
- a pressure differential across the piston head member is measured as a pressure of the fluid in the passageway on the axial upstream side of the piston head member minus a pressure of the fluid in the passageway on the axial downstream side of the piston head member,
- the piston head member having a peripheral circumferential edge portion wherein when the edge portion of the piston head member is in the tube upstream portion engagement between the edge portion and the tube inner wall of the tube upstream portion prevents fluid flow axially therebetween, and when the edge portion of the piston head member is in the tube downstream portion interaction between the edge portion of the piston head member and the tube downstream portion permits fluid flow downstream therepast,
- wherein when the pressure differential is less than or equal to the first pressure level the edge portion of the piston head member is in the tube upstream portion and when the pressure differential is greater than the first pressure level the edge portion of the piston head member is in the tube downstream portion.
- Accordingly, in accordance with the second aspect, the present invention provides a piston-forming element for reciprocal sliding within a chamber in a piston pump,
- the piston-forming element disposed about a central axis and having an inner head portion, an outer base portion and a tubular portion intermediate the head portion and the base portion,
- the tubular member coupled at an outer end to the base portion and at an inner end to the head portion,
- a head disc extending radially outwardly from the head portion substantially preventing fluid flow in the chamber past the head disc in an inward direction and permitting fluid flow in the chamber past the head disc in an outward direction,
- a base disc extending radially outwardly from the stem of the base portion axially outwardly from the head disc engaging the chamber wall circumferentially thereabout substantially preventing fluid flow in the chamber past the base disc in an inward direction,
- the base portion having a central axially extending hollow stem having a central passageway open at an outer end forming an outlet,
- the passageway extending from the outlet inwardly to an inner end open to the chamber between the head disc and the base disc,
- the tubular member having a wall extending between inner end and the outer end,
- the wall having the shape of a solid of revolution rotated about the central axis,
- the wall having a radially outwardly directed outer wall surface and a radially inwardly directed inner wall surface,
- at least one opening radially through the wall member from the outer wall surface to the inner wall surface,
- the tubular member reducing in length axially between the base portion and the head portion when axially directed compression forces are applied to the tubular member by the base portion,
- the tubular member being resilient having an inherent bias to assume an initial unbiased configuration of an unbiased length measured axially along the central axis, the tubular member resiliently deflectable to biased configurations each having a length measured axially along the central axis less than the unbiased length, the inherent bias of the resilient member biasing the tubular member to return towards the unbiased configuration from any one of the biased configurations,
- with a reduction in the length of the tubular member as measured axially along the central axis the outer wall surface increases in convexity as seen in cross-sectional side view in any flat plane including the central axis extending radially from the axis.
- In a further perspective of the second aspect, the present invention provides a pump for dispensing fluids from a reservoir, comprising:
- a piston chamber-forming member having an elongate chamber, said chamber having a chamber wall, an outer open end and an inner end in communication with the reservoir;
- a one-way valve between the reservoir and the chamber permitting fluid flow through the inner end of the chamber, only from the reservoir to the chamber;
- a piston-forming element slidably received in the chamber extending outwardly from the open end thereof;
- the piston-forming element having an inner head portion, an outer base portion and a variable length portion intermediate the head portion and the base portion joining the head portion and the base portion,
- a head disc extending radially outwardly from the head portion engaging the chamber wall circumferentially thereabout to substantially prevent fluid flow in the chamber past the head disc in an inward direction, the head disc elastically deforming away from the chamber wall to permit fluid flow in the chamber past the head disc in an outward direction,
- a base disc extending radially outwardly from the stem of the base portion axially outwardly from the head disc engaging the chamber wall circumferentially thereabout to substantially prevent fluid flow in the chamber past the base disc in an inward direction,
- the base portion having a central axially extending hollow stem having a central passageway open at an outer end forming an outlet,
- the passageway extending from the outlet inwardly to an inner end open to the chamber between the head disc and the base disc,
- the piston-forming element received in the piston chamber-forming member reciprocally coaxially slidable inwardly and outwardly by movement of the base portion in the chamber between a retracted position and an extended position in a cycle of operation to draw fluid from the reservoir and dispense it from the outlet,
- the piston-forming element and the chamber coaxially disposed about a central axis,
- the variable length portion comprising a tubular member coupled at an outer end to the base portion and at an inner end to the head portion,
- the tubular member transmitting axially directed tension force applied thereto by the base portion from the base portion to the head portion,
- the tubular member reducing in length axially between the base portion and the head portion when axially directed compression forces are applied to the tubular member by the base portion,
- the tubular member having a wall extending between inner end and the outer end,
- the wall having the shape of a solid of revolution rotated about the central axis,
- the wall having a radially outwardly directed outer wall surface and a radially inwardly directed inner wall surface,
- at least one opening radially through the wall member from the outer wall surface to the inner wall surface,
- the tubular member being resilient having an inherent bias to assume an initial unbiased configuration of an unbiased length measured along the central axis, the tubular member resiliently deflectable to biased configurations each having a length measured along the central axis less than the unbiased length, the inherent bias of the resilient member biasing the tubular member to return towards the unbiased configuration from any one of the biased configurations,
- a reduction in the length of the tubular member as measured along the central axis corresponds to the outer wall surface increasing in convexity as seen in cross-sectional side view in flat planes including the central axis extending radially from the axis.
- Further aspects and advantages of the present invention will become apparent from the following description taken together with the accompanying drawings in which:
-
Figure 1 is a cross-sectional side view of a pump in accordance with a first embodiment of the present invention with a piston in an uncompressed condition; -
Figure 2 is a cross-sectional side view of the pump piston of the pump shown inFigure 1 in the same uncompressed condition as inFigure 1 ; -
Figure 3 is a cross-sectional side view of the pump piston as inFigure 2 but in a first compressed condition; -
Figure 4 is a cross-sectional side view of the pump piston as inFigure 2 but in a second compressed condition; -
Figure 5 is a pictorial view of a valve piston member of the pump piston of the pump shown inFigure 1 : -
Figure 6 is a cross-sectional end view of the valve piston member of the pump piston along section line 6-6' inFigure 2 ; -
Figure 7 is a pictorial view of the pump piston ofFigure 1 but in the first compressed condition ofFigure 3 ; -
Figure 8 is an exploded pictorial view of the pump piston ofFigure 7 ; -
Figure 9 is a partial pictorial view showing the valve piston member ofFigures 7 and8 cross-sectioned along section 9-9' inFigure 3 ; -
Figure 10 is a cross-sectional end view of the piston ofFigure 3 along section line 9-9' inFigure 3 ; -
Figures 11 ,12 ,13 and14 are cross-sectional views of the pump ofFigure 1 , respectively, with inFigure 11 , the pump piston in an extended position with the valve piston member in the uncompressed condition ofFigure 2 , with inFigure 12 , the pump piston in an extended position and the valve piston member in the compressed condition ofFigure 3 , with inFigure 13 , the pump piston in a retracted position and the valve piston member in the compressed condition ofFigure 3 ; and with inFigure 14 , the pump piston in a retracted position and with the valve piston member in the uncompressed condition ofFigure 2 ; -
Figure 15 is a pictorial view similar toFigure 5 but of a second embodiment of a valve piston member adapted for substitution for the valve piston member inFigure 5 and showing the valve piston member in an uncompressed condition; -
Figure 16 is a pictorial view of the valve piston member ofFigure 15 in a compressed condition; -
Figure 17 is a cross-sectional end view similar toFigure 6 but of the valve piston member ofFigure 15 along section line A-A' inFigure 15 ; -
Figure 18 is a cross-sectional side view similar toFigure 2 but of a third embodiment of a piston pump adapted for substitution for the pump piston inFigure 1 and with the valve piston member in an uncompressed condition; -
Figure 19 is a cross-sectional side view similar toFigure 1 but of a fourth embodiment of a pump and with the pump piston in an extended position and a valve piston member in an uncompressed condition; -
Figure 20 is a cross-sectional side view similar toFigure 2 but of a fifth embodiment of a pump piston adapted for substitution for the pump piston inFigure 1 and with the valve piston member in an uncompressed condition; -
Figure 21 is a cross-sectional view similar toFigure 18 of a sixth embodiment of a pump piston for use in substitution of the pump piston inFigure 1 ; -
Figure 22 is a cross-sectional view of a pump in accordance with the seventh embodiment of the invention with the pump piston in an extended position and a valve piston member in an uncompressed condition; -
Figure 23 is a cross-sectional side view of the pump piston of the pump shown inFigure 22 with the valve piston member in the same uncompressed condition as inFigure 22 ; -
Figure 24 is a cross-sectional side view of the pump piston as inFigure 22 but with the valve piston member in a first compressed condition; -
Figure 25 is a cross-sectional side view of the pump piston as inFigure 22 but with the valve piston member in a second compressed condition; -
Figure 26 is a cross-sectional side view of an eighth embodiment of a pump piston for use in the pump shown inFigure 22 with a valve piston member in an uncompressed condition; -
Figure 27 is a cross-sectional side view of a ninth embodiment of a pump piston for use in the pump shown inFigure 22 with a valve piston member in an uncompressed condition; -
Figure 28 is a cross-sectional side view of a tenth embodiment of a pump piston for use in the pump shown inFigure 22 with a valve piston member in an uncompressed condition; -
Figure 29 is a cross-section through the valve body ofFigure 28 along section line B-B'; -
Figure 30 is a cross-sectional side view of an eleventh embodiment of a pump piston for use in the pump shown inFigure 22 with a valve piston member in an uncompressed condition; -
Figure 31 is a cross-sectional side view of a twelfth embodiment of a pump piston for use in the pump shown inFigure 22 with a valve piston member in an uncompressed condition; -
Figure 32 is a cross-sectional side view of a thirteenth embodiment of a pump piston for use in the pump shown inFigure 22 with a valve piston member in an uncompressed condition; -
Figure 33 is a cross-sectional side view of a fourteenth embodiment of a pump piston for use in the pump shown inFigure 22 with a valve piston member in an uncompressed condition; -
Figure 34 is a schematic side view of a fluid dispenser in accordance with a fifteenth preferred embodiment of the present invention; -
Figure 35 is a side view showing a portion ofFigure 34 enlarged; -
Figure 36 is an enlarged side view similar to that shown inFigure 35 but showing a sixteenth embodiment of a pump piston of the present invention; -
Figure 37 is a side view the same as in an unbiased condition inFigure 36 with the pump piston in a biased condition; -
Figure 38 is a schematic side view of a fluid dispenser in accordance with a seventeenth embodiment of the present invention; -
Figure 39 is a side view showing a portion ofFigure 37 enlarged; -
Figure 40 is a schematic side view of a portion of a fluid dispenser in accordance with an eighteenth embodiment of the present invention having similarities to the embodiment shown inFigure 39 ; -
Figure 41 is a pictorial view of the valve piston member ofFigure 40 . -
Figure 42 is a perspective view of a valve piston member in accordance with a nineteenth embodiment of the present invention; -
Figure 43 is a pictorial view of a piston valve member in accordance with a twentieth embodiment of the present invention; -
Figure 44 is a pictorial view of a piston valve member in accordance with a twenty-first embodiment of the present invention; -
Figure 45 is a schematic side view of a portion of a fluid dispenser in accordance with a twenty-second embodiment of the present invention having similarities to the embodiment shown inFigure 40 ; -
Figure 46 is a pictorial view of the piston valve member ofFigure 45 ; and -
Figure 47 is a schematic side view of a portion of a fluid dispenser in accordance with a twenty-third embodiment of the present invention having similarities to the embodiment shown inFigure 40 . - Reference is made first to the pump shown in
Figure 1 comprising apump assembly 10 secured to a reservoir orcontainer 26 having a threadedneck 34. The pump assembly has abody 12, a one-way valve 14 and apump piston 16. - The
body 12 provides acylindrical chamber 18 in which thepump piston 16 is axially reciprocally slidable in a cycle of operation so as to draw fluid from within thecontainer 26 and dispense it out of anoutlet 54. Thechamber 18 has acylindrical chamber wall 20 disposed coaxially about acentral chamber axis 22. - The
pump piston 16 is shown as preferably formed from two elements, namely: avalve piston member 15 and avalve body 17. Functionally, thepump piston 16 has ahead portion 47, a variable lengthintermediate portion 45 and abase portion 49. Thevalve piston member 15 is preferably an integral member as shown forming both thehead portion 47 and the variable lengthintermediate portion 45. In the first preferred embodiment, thevalve piston member 15 is an integral member formed from a resilient material so as to provide the variable lengthintermediate portion 45 to function as a resilient spring. - The
head portion 47 includes a centrally extendinghead stem 30 upon which ahead disc 48 is mounted. Thehead disc 48 extends radially outwardly from the head stem 30 as a circular resilient flexible disc located at the inwardmost end of thehead portion 47 and extending radially therefrom. Thehead disc 48 is sized to circumferentially abut theinner chamber wall 20 substantially preventing fluid flow therepast inwardly in thechamber 18. Thehead disc 48 is formed as a thin resilient disc having an elasticallydeformable edge portion 48a to engage thechamber wall 20. The edge portion extends radially outwardly and in a direction axially outwardly of thechamber 18. The edge portion is adapted to deflect radially inwardly away from thechamber wall 20 to permit fluid flow outwardly in thechamber 18 therepast. - As best seen in
Figures 6 and8 , axially outwardly of thehead disc 48, thehead stem 30 has acenter 33 coaxial about the axis from which fourelongate arms 32 extend radially outwardly and axially to provide an X shape in cross-section as inFigures 6 and8 . Eacharm 32 carries at its axial end a radially outwardly extending hookingmember 34 with an axially inwardly directed catchingsurface 35. - The variable length
intermediate portion 45 comprises an elongatetubular member 200 disposed to bridge between thehead portion 47 and thebase portion 49 joining them together axially spaced apart. Thetubular member 200 has aninner end 202 and anouter end 204. Theinner end 202 of thetubular member 200 is fixedly coupled to thehead portion 47 by being formed integrally therewith. Theouter end 204 of thetubular member 200 engages thebase portion 49. Thetubular member 200 is coupled to thehead portion 47 and thebase portion 49 in a manner so as to not interfere with the engagement of thehead disc 48 and abase disc 50 carried on thebase portion 49 with theside wall 20 of the chamber. - The
tubular member 200 has awall 206 extending between theinner end 202 and theouter end 204. Thewall 206 has a radially inwardly directedinner wall surface 208 and a radially outwardly directedouter wall surface 210. Thewall 206 has the shape of a solid of revolution rotated about thecentral axis 22. The wall extends circumferentially entirely about thecentral axis 22, that is, 360 degrees about thecentral axis 22. Each of theinner end 202 and theouter end 204 is an annular ring that extends annularly 360 degrees about thecentral axis 22. - A plurality of
openings 212 extend radially through thewall 206 between theinner wall surface 208 and theouter wall surface 210. Theopenings 212 each have an axial extent. Theopenings 212 are spaced circumferentially about thetubular member 200 with eachopenings 212 spaced circumferentially from itsadjacent openings 212 by anaxially extending web 213. Preferably, as shown, theopenings 212 are identical and evenly spaced circumferentially byidentical webs 213. Eachopening 212 is shown to be defined between aninner end surface 501, anouter end surface 503 and twoside surfaces opening 212 is axially elongate and has an axial extent between theinner end surface 501 and theouter end surface 503. Each opening has a circumferential extent between the side surfaces 505 and 507. - In operation of the pump, fluid which moves through the
pump piston 16 radially outwardly of thehead disc 48 passes through theopenings 212 to reach theoutlet 54. - The valve body or
base portion 49 has abase stem 46 that carries thebase disc 50, locatingdisc 66, locatingwebs 67 and anengagement flange 62. Thebase disc 50 is a circular resilient flexible disc located on thestem 46 spaced axially outwardly from thehead disc 48. Thebase disc 50 extends radially outwardly from thestem 46 to circumferentially engage thechamber wall 20 substantially preventing fluid flow therebetween outwardly in thechamber 18. As with thehead disc 48, thebase disc 50 is preferably formed as thin resilient disc, in effect, having an elastically deformable edge portion 30a to engage thechamber wall 20. Thestem 46 has acentral passageway 52 extending along theaxis 22 from aninner inlet end 58 located on thestem 46 between thehead disc 48 and thebase disc 50 to theoutlet 54 at the outer end of thebase portion 49. Thepassageway 52 permits fluid communication through thebase portion 49 past thebase disc 50, between theinlet end 58 and theoutlet 54. Locatingdiscs 66 and locatingwebs 67 best seen inFigure 7 are provided to engage thechamber wall 20 so as to assist in maintaining thebase portion 49 axially centered within thechamber 18 when sliding axially in and out of thechamber 18. Thestem 46 comprises a tubular member and can be seen to have thepassageway 52 extend therethrough between theoutlet 54 and theinlet end 58 with theinlet end 58 open to thechamber 18 between thehead disc 48 and thebase disc 50. - Each of the
base portion 49 and thehead portion 47 is circular in any in cross-section normal theaxis 22 therethrough. Each of thebase portion 49 and thehead portion 47 is adapted to be slidably received inchamber 18 coaxially within thechamber 18. - As seen in
Figure 3 , thepassageway 52 has its side wall 52a formed to provide an axially outwardly directedcatch surface 290 which forms a hook member in axial opposition to the axially inwardly directed catchingsurface 35 to be engaged by the hookingmember 34 of thehead stem 30 and limit inward axial movement of thehead portion 47 relative thebase portion 49. Thecatch surface 290 is provided as an axially outwardly directed shoulder between an inner portion of thepassageway 52 of a first diameter and an outer portion of a larger diameter. - The
engagement flange 62 is provided on thestem 46 for engagement as by an actuator, not shown, to move thebase portion 49 inwardly and outwardly. Theengagement flange 62 may also serve the function of a stopping disc to limit axial inward movement of thepump piston 16 by engagement with theouter end 23 of thebody 12. Thestem 46 is shown to extend outwardly from theengagement flange 62 to thedischarge outlet 54 as a relatively narrowhollow tube 138 with thepassageway 52 coaxially therethrough. - The one-
way valve 14 comprises a unitary piece of resilient material having a resilient, flexible,annular rim 132 for engagement with the side wall of thechamber 18. The one-way valve 14 is integrally formed with a shoulderingbutton 134 which is secured in a snap-fit inside anopening 136 in a central upper end of thechamber 18. - As seen in
Figure 1 , an annularinner compartment 111 is formed inside thechamber 18 between the one-way valve 14 and thehead disc 48 and an annularouter compartment 112 is formed inside thechamber 18 between thehead disc 48 and thebase disc 50. The volume of the annularouter compartment 112 varies with variance of the axial length of the variable lengthintermediate portion 45 of thepump piston 16. - The
body 12 carries an outercylindrical portion 40 carryingthreads 130 to cooperate with threads formed on the threadedneck 34 of thecontainer 26. - In use, the
pump assembly 10 is preferably orientated such that such that theoutlet 54 is directed downwardly, however, this is not necessary. - The
tubular member 200 has an inherent resiliency by reason of being formed from a suitable resilient material, preferably plastic material. The inherent resiliency of thetubular member 200 biases thetubular member 200 to adopt an unbiased configuration of a maximum axial length measured along the central axis. When thetubular member 200 is subjected to axially directed compression forces thetubular member 200 compresses axially such that its axial length as measured along thecentral axis 22 reduces and when such compressive forces are released, thetubular member 200 increases in length expanding towards the unbiased condition.Figure 2 shows thepump piston 16 and itsvalve piston member 15 in an uncompressed condition.Figure 3 shows thepump piston 16 and itsvalve piston member 15 in a first compressed condition in which the variable lengthintermediate portion 45 and itstubular member 30 are compressed to be of reduced axial length compared toFigure 2. Figure 4 shows thepump piston 16 and itsvalve piston member 15 in a second compressed condition compressed to be of reduced axial length compared toFigure 3 . - The
tubular member 200 is disposed about thecentral axis 22 bridging between thehead portion 47 and thebase portion 49 and acts in the manner of a spring to urge thehead portion 47 andbase portion 49 axially apart. - The
inner end 202 of thetubular member 200 is fixed to the head stem 30 radially inwardly from thehead disc 48 by being formed integrally therewith. Thebase portion 49 is arranged such that theouter end 204 of thetubular member 200 engages thebase stem 46 of thebase portion 49 radially inwardly from thebase disc 50. - As shown in
Figure 2 , thebase portion 49 provides an axially inwardly directedsurface 300 at its inner end between theinner inlet end 58 of thepassageway 52 and thebase disc 50 which surface 300 is to be engaged by theouter end 204 of thetubular member 200. In the first embodiment, anannular groove 301 is provided in thesurface 300 open axially inwardly within whichgroove 301 theouter end 204 of thetubular member 200 is seated. Engagement between theannular groove 301 and theouter end 204 of thetubular member 200 assists in maintaining thetubular member 200 coaxially disposed about thecentral axis 22. As shown, thegroove 301 preferably has an outer side surface which is directed radially inwardly to engage theouter surface 210 of the wall of thetubular member 200. Thegroove 301 also has an inner side surface directed radially outwardly and adapted to engage theinner surface 208 of the wall of thetubular member 200. Thegroove 301 could be configured to provide merely the outer side or the inner side surface and still function to restrain the outer end of thetubular member 200. - The variable length
intermediate portion 45 has an axial length defined as a length measured along thecentral axis 22 as between thehead disc 48 and thebase disc 50. This axial length is measured along theaxis 22 between acenter 218 on thehead portion 47 and acenter 220 of thebase disc 50. The axial length is indicated as L onFigure 2 and is variable between a maximum length and a minimum length due to the ability of theelongate members 200 to deflect. - The
pump piston 16 shown in each ofFigures 5 and6 show thepump piston 16 in an uncompressed condition ofFigure 2 . In contrast,Figures 7 to 10 show thepump piston 16 in the first compressed condition ofFigure 3 . - The
pump assembly 10 is shown inFigures 12 ,13 and14 in use in a cycle of operation of the pump.Figures 11 and14 show thepump piston 16 within thechamber 18 of thebody 12 in an uncompressed condition (also sometimes referred to herein as an expanded condition) as seen inFigure 2 in which the variable lengthintermediate portion 45 is in its maximum length. With movement of thebase portion 49 outwardly in thechamber 18 as from the position ofFigure 14 , resistance to movement of thehead portion 47 and particularly itshead disc 48 within thechamber 18 will give rise to tension forces being applied across thetubular member 200. The response of thetubular member 200 to such tension force will depend upon the nature and resiliency of thetubular member 200 and the amount of the tension force. -
Figures 12 and13 show thepump piston 16 received in thechamber 18 of thebody 12 with the variable lengthintermediate portion 45 in a first compressed condition as seen inFigure 3 . With movement of thebase portion 49 inwardly in thechamber 18, resistance to inward movement of thehead portion 47 and notably resistance to movement of thehead disc 48 inwardly in thechamber 18 results in compressive forces being applied to the variable lengthintermediate portion 45 between thebase portion 49 and thehead portion 47. Such compressive forces cause thetubular member 200 to deform to reduce the axial length of the variable lengthintermediate portion 45 to a reduced length compressed condition as seen inFigures 12 and13 . - In operation of the pump, the relative tension forces and compression forces which may be applied through the variable length
intermediate portion 45 between thebase portion 49 and thehead portion 47 will cause the variable lengthintermediate portion 45 to adopt configurations between an expanded condition and a compressed condition. The relative resistance of thehead portion 47 to sliding within thechamber 18 is affected by many factors including the friction to movement of thehead portion 47 within thechamber 18, inwardly and outwardly, the nature of the fluid in the reservoir having regard to, for example, its viscosity and temperature, the speed with which thebase portion 49 is moved and various other factors which will be apparent to a person skilled in the art. A person skilled in the art by simple experimentation can determine suitable configurations for theintermediate member 45 so as to provide for the axial length of the variable length portion to vary between a suitable minimum length and a suitable maximum length in cyclical movement of thepump piston 16 in a cycle of operation. - The
outer wall surface 210 of thewall 206 of thetubular member 200 as seen in side view inFigure 2 in the uncompressed condition is convex, that is, theouter wall surface 210 bows radially outwardly. - As the
tubular member 200 is axially compressed to the reduced length compressed condition ofFigure 3 , the convexity of theouter wall surface 210 increases. As seen inFigure 3 , when in the compressed condition, theouter wall surface 210 is convex, however, bowed outwardly to an extent greater than in the uncompressed condition ofFigure 2 . - The
openings 212 are provided through thewall 206 such that the openings change in relative shape with axial deflection of thetubular member 200. Eachopening 212 provides a passage through which fluid may flow through thewall 206. In the uncompressed condition ofFigure 5 , each opening 12 provides a minimum cross-sectional area for fluid flow therebetween. The cross-sectional area of the passage throughopenings 212 for fluid flow therethrough preferably increases as thetubular member 200 is deflected axially from the expanded condition to the compressed condition by reason of the circumferential extent of each opening between the side surfaces 505 and 507 increasing as thewall 206 bows out and theouter wall surface 210 increases in convexity. While not necessary, having the cross-sectional area of the passage through each opening increase as thetubular member 200 is compressed is advantageous since during operation of the pump, a larger volumetric fluid flow through thetubular member 200 is required when thetubular member 200 is compressed. - Reference is made to
Figure 6 which shows a cross-sectional end view through thepump piston 16 in the uncompressed condition ofFigure 2 in which theopenings 212 are shown in end cross-section disposed between thewebs 213. Reference is made toFigure 10 which shows a similar cross-sectional end view as inFigure 6 , however, with thepump piston 16 in a compressed condition ofFigure 3 in which thetubular member 200 is axially compressed compared toFigure 2 . As may be seen by a comparison ofFigure 6 withFigure 10 , thewebs 213 inFigure 10 are located radially farther outwardly from thecentral axis 22 with a result that the circumferential extent of eachopening 212 has been increased by reason that side surfaces 505 and 507 defining eachopening 212 are circumferentially farther apart inFigure 10 than inFigure 6 . The cross-sectional area for fluid flow through each opening is a function of the circumferential extent of the opening. Generally, in the first embodiment with an increase in circumferential extent, the cross-sectional area of the opening increases. - The pump assembly operates in a cycle of operation in which the
pump piston 16 is reciprocally moved relative thebody 12 inwardly in a retraction stroke and outwardly in a withdrawal stroke. - During movement of the
head portion 47 inwardly into the chamber, since fluid is prevented from flowing outwardly past thedisc 50, pressure is created in theinner compartment 111 formed in thechamber 18 between thehead disc 48 and the one-way valve 14. This pressure urgesrim 132 of the oneway valve 14 radially inwardly to a closed position abutting thechamber wall 20. As this pressure increases,head disc 48 deflects at its periphery so as to come out of sealing engagement with thechamber wall 20 and permits fluid to flow outwardlypast head disc 48 into the annularouter compartment 112 between thehead disc 48 and thesealing disc 50 through thetubular member 200 via theopenings 212 and hence out ofchamber 18 via thepassageway 52. - During a withdrawal stroke in which the
pump piston 16 is moved outwardly from thechamber 18, the withdrawal of thepump piston 16 causes the one-way valve 14 to open with fluid to flow pastannular rim 132 which is deflected radially inwardly into theinner compartment 111 in thechamber 18. In the withdrawal stroke,head disc 48 remains substantially undeflected and assists in creating a vacuum in theinner compartment 111 to deflectrim 132 and draw fluidpast rim 132. - The
head disc 48, on one hand, substantially prevents flow inwardly therepast in the withdrawal stroke and, on the other hand, deforms to permit flow outwardly therepast in the retraction stroke. Thehead disc 48 shown facilitates this by being formed as a thin resilient disc, in effect, having an elastically deformable edge portion nearchamber wall 20. - When not deformed,
head disc 48 abuts thechamber wall 20 to form a substantially fluid impermeable seal. When deformed, as by itsedge portion 48a being bent away fromwall 20, fluid may flow outwardly past the head disc,Head disc 48 is deformed when the pressure differential across it, that is, when the pressure on the upstream side is greater in theinner compartment 111 than the pressure on the downstream side in theouter compartment 112 by an amount greater than the maximum pressure differential which the edge portion of the head disc can withstand without deflecting. When this pressure differential is sufficiently large, the edge portion of the head disc deforms and fluid flows outwardly therepast. When the pressure differential reduces to less than a given pressure differential, thehead disc 48 returns to its original inherent shape substantially forming a seal with thewall 20. -
Figures 11 to 14 show different conditions the variable lengthintermediate portion 45 assumes in a cycle of operation. In this cycle of operation, thebase portion 49 is moved in a retraction stroke from an extended position as seen inFigure 11 to a retracted position as seen inFigure 13 . In a withdrawal stroke, thebase portion 49 is moved from the retracted position ofFigure 13 to the extended position shown inFigure 11 . -
Figure 11 illustrates thepump piston 16 with thebase portion 49 in the extended position and thepump piston 16 and itsvalve piston member 15 and its variable lengthintermediate portion 45 in an uncompressed condition. In the extended position and uncompressed condition ofFigure 11 , theouter compartment 112 formed in thechamber 18 between thehead disc 48 andbase disc 49 is at a maximum volume. FromFigure 11 , thebase portion 49 is moved inwardly in a retraction stroke to assume the condition ofFigure 12 in which thepump piston 16, itsvalve piston member 15 and its variable lengthintermediate portion 45 are a compressed condition. On thebase portion 49 moving inwardly in thechamber 18 from the position ofFigure 11 , while the length of the variable lengthintermediate portion 45 is greater than its minimum length, resistance to movement of thehead portion 47 and itshead disc 48 inwardly in thechamber 18 is sufficient that the length of the variable lengthintermediate portion 45 decreases toward its minimum length as shown inFigure 12 before thehead portion 47 is moved inwardly in thechamber 18. Thus, in movement of thebase portion 49 inwardly from the position ofFigure 11 , compressive forces will be applied to the variable lengthintermediate portion 45 which forces will reduce the length of the variable lengthintermediate portion 45 until the compressive forces transferred by the variable lengthintermediate portion 45 are greater than the resistance to movement of thehead portion 47 inwardly in the chamber. The compressive forces may be developed such that the variable length intermediate portion substantially decreases to its minimum length before thehead portion 47 is substantially moved inwardly. - From the position shown in
Figure 12 , with the variable length portion in the compressed condition, further inward movement of thebase portion 49 in the retraction stroke moves thepump piston 16 with the variable lengthintermediate portion 45 maintained in the compressed condition inwardly to the position ofFigure 13 in which thebase portion 49 is fully retracted and the variable lengthintermediate portion 45 is compressed.Figure 13 thus represents a retracted position and compressed condition of thepump piston 16 in which thepump piston 16, itsvalve piston member 15 and its variable lengthintermediate portion 45 are compressed. - From the position of
Figure 13 , in a withdrawal stroke, thebase portion 49 is moved outwardly in the chamber. In movement of thebase portion 49 from the position ofFigure 13 to the position ofFigure 14 , while the length of the variable lengthintermediate portion 45 is less than the maximum length, resistance to movement of thehead portion 47 and therefore itshead disc 48 outwardly in thechamber 18 is sufficient that the length of the variable lengthintermediate portion 45 increases toward the maximum length before thehead portion 47 is moved outwardly in thechamber 18. In this regard, in moving from the position ofFigure 13 to the position ofFigure 14 , outward movement of thebase portion 49 applies tension forces to the variable lengthintermediate portion 45. These tension forces will act on the variable lengthintermediate portion 45 expanding thevariable length portion 45 until such time as the tension forces which are transferred by the variable lengthintermediate portion 45 from thebase portion 49 thehead portion 47 are greater than the resistance of the head portion for movement outwardly in the chamber. The tension forces may be developed such that the variable lengthintermediate portion 45 substantially increases to its maximum length before thehead portion 47 is substantially moved outwardly. - From the position of
Figure 14 , the withdrawal stroke is completed by movement to the position ofFigure 11 . In moving from the position ofFigure 14 to the position ofFigure 11 , the variable lengthintermediate portion 45 is maintained in the expanded condition with the variable lengthintermediate portion 45 at its maximum length and tension forces caused by movement of thebase portion 49 are transferred via the variable lengthintermediate portion 45 to thehead portion 47. - In a cycle of operation in moving from the position of
Figure 12 to the position ofFigure 13 , the volume of theinner compartment 111 reduces and hence fluid is discharged from theinner compartment 111 past thehead disc 48, through thetubular member 200 via theopenings 212 through thepassageway 52 out theoutlet 54 since fluid within thechamber 18 is prevented from passing inwardly past the oneway valve 14 and is prevented from passing outwardly past thebase disc 50. In moving from the position ofFigure 11 to the position ofFigure 13 , pressure is created within theinner compartment 111 which closes the one-way valve 14. Fluid within theinner compartment 111 becomes compressed by movement of thehead disc 48 inwardly. Such pressure causes the deformable edge portion of thehead disc 48 to deflect away from thechamber wall 20 thus permitting flow of fluid from theinner compartment 111 into theouter compartment 112. Since the volume of theouter compartment 112 remains the same in the compressed condition, any fluid which is passed outwardly past thehead disc 48 causes fluid within theouter compartment 112 to be dispensed through thetubular member 200 via theopenings 212 and through thepassageway 52 out from theoutlet 54. - In movement from the position of
Figure 13 to the position ofFigure 14 , the volume of theouter compartment 112 increases. This increase in volume of theouter compartment 112 causes a drawback of fluid in thepassageway 52 from theoutlet 54 back into theouter compartment 112 with some fluid moving inwardly through the tubular member via theopenings 212. This drawback may not only be a drawback of fluid in thepassageway 52 but also possibly of any air existing in thepassageway 52 or at theoutlet 54. - To facilitate drawback of fluid, the relative nature of the
head disc 48 and thebase disc 50 and the engagement of each with thechamber wall 20 are preferably selected such that vacuum created within theouter compartment 112 will drawback fluid from thepassageway 52 rather than deflect thehead disc 48 to draw liquid from theinner compartment 111 past thehead disc 48 into theouter compartment 112, or, deflect thebase disc 50 to draw atmospheric air between thebase disc 50 and thechamber wall 20. - In movement from the position of
Figure 14 to the position ofFigure 11 , the volume in theouter compartment 112 is maintained substantially constant with thevariable length portion 45 in a maximum length condition, however, movement of thehead disc 48 outwardly increases the volume in theinner compartment 111 thus drawing fluid from the reservoir inwardly past the one-way valve 14 into theinner compartment 111. - The
drawback pump assembly 10 in accordance with the present invention may be used in manually operated dispensers such as those in which, for example, thepump piston 16 is moved manually as by a user engaging an actuator such as a lever which urges thepump piston 16 either outwardly or inwardly. The drawback pump can also be used in automated systems in which a user will activate an automated mechanism to move thepump piston 16 in a cycle of operation. - A preferred arrangement for operation of the
drawback pump assembly 10 in accordance with the present invention is for the pump assembly to assume a position between the condition shown inFigure 14 and the condition shown inFigure 11 as a rest position between cycles of operation. For example, in the context of a manual dispenser, the dispenser may be arranged such that thebase portion 49 is biased to assume as a rest position between cycles of operation, the extended position seen inFigure 11 . A person would manually operate a lever to move the dispenser from the position ofFigure 11 to the position ofFigure 13 . On release of the lever, a spring will return the lever andbase portion 48 to the position ofFigure 11 . In such a cycle of operation, on movement from the position ofFigure 11 to the position ofFigure 13 , fluid is dispensed from theoutlet 54. In a return stroke, for example, due to the bias of a spring, fluid in thepassageway 52 is withdrawn in movement from the position ofFigure 13 to the position ofFigure 14 and theinner compartment 111 is filled in movement of the piston to the rest position ofFigure 11 . In automated operation, a rest position between cycles may preferably be at some point in between the position ofFigure 14 and the position ofFigure 11 . - The preferred embodiment illustrates the
valve piston member 15 consisting of thepiston head portion 47 andintermediate portion 45 as being formed from a unitary piece of plastic preferably by injection molding. It is to be appreciated that a similar structure could be formed with each of thehead portion 47,base portion 49 andintermediate portion 45 being separately formed. Also the variable lengthintermediate portion 45 could be formed together with either or both of thehead portion 47 and thebase portion 49 as a unitary piece of plastic. - In the context of the embodiment of
Figures 1 to 14 , preferably thetubular member 200 has an inherent unbiased condition when molded. - An assembled
pump piston 16 will have an inherent unbiased condition as seen inFigure 2 which it will assume when no axial forces are applied to it. The inherent unbiased condition of thepump piston 16 depends on the inherent unbiased condition of thehead portion 47, thebase portion 49 and theintermediate portion 45. In the preferred embodiment, effectively only thetubular member 200 is axially deformable. - In the preferred embodiment of
Figures 1 to 14 , when thepump piston 16 is in the unbiased inherent condition, thetubular member 200 is either in its unbiased inherent condition or slightly compressed from its unbiased inherent condition. InFigure 2 , if thetubular member 200 is in its unbiased inherent condition, then the axial length between theouter end 204 of thetubular member 200 and the catchingsurface 35 on thehead stem 30 is equal to the axial length between thegroove 301 on thebase portion 49 and thecatch surface 290 on thebase portion 49. - In
Figure 2 , if thetubular member 200 is in a condition compressed from its unbiased inherent condition, then the axial length between theouter end 204 of thetubular member 200 and the catchingsurface 35 on thehead stem 30 is less than the axial length between thegroove 301 on thebase portion 49 and thecatch surface 290 on thebase portion 49. - The
tubular member 200 is axially compressible from the inherent unbiased condition to assume conditions in which its axial length is reduced compared to the inherent unbiased condition. When deformed to a reduced length condition and released, the tubular member returns to its inherent unbiased condition. Depending on the configuration of thetubular member 200 in the inherent unbiased condition, the tubular member can also be axially expandable from the inherent unbiased condition to a stretched position in which its axial length is increased compared to the inherent unbiased condition. For example, if the wall of the tubular member is in the inherent unbiased condition, not straight but bowed, then on applying axial tension forces, the wall may be deformed against its bias to become straight increasing the axial length. As another example, if the wall of the tubular member is straight in the inherent unbiased condition, for example, frustoconical, then the tubular member cannot be stretched and has its maximum axial length as the inherent unbiased condition. When thepiston 16 in its unbiased inherent condition, having thetubular member 200 compressed has the advantage that the inherent bias of thetubular member 200 will assist in ensuring that theouter end 204 of thetubular member 200 is maintained and urged into engagement with thegroove 301. - The
tubular member 200 is selected so as to provide thehead portion 47 and itshead disc 48 maintained coaxially arranged within the chamber. - The preferred embodiment of
Figure 1 illustrates a four-piece pump having as the four pieces, thebody 12, the one-way valve 14 and the two-piece pump piston 16, and in which thechamber 18 in thebody 12 has a constant diameter. The invention of the present application is also adaptable for use with two piece pumps having a stepped chamber. Such pumps have been disclosed inU.S. Patent 5,676,277 to Ophardt, issued October 14, 1997 , the disclosure of which is incorporated herein by reference. - Reference is made to
Figures 15 to 17 showing a second embodiment in which avalve piston member 15 comprising ahead portion 47 and a variable length intermediatetubular portion 45 is adapted for use with abase portion 49 identical to that shown, for example, inFigure 1 with the first embodiment. In the second embodiment ofFigures 15 to 17 , the only difference over the first embodiment ofFigures 1 to 14 is the configuration of theopenings 212. As can be seen inFigures 15 and16 , each of the side surfaces 507 and 509 which define theopenings 212 therebetween converges at a commoninner point 501 and at a commonouter point 503.Figure 15 illustrates a condition in which the axial length of thetubular member 200 is greater than the axial length of thetubular member 200 inFigure 16 . - As can be seen in
Figure 15 , each of the side surfaces 503 and 507 abut each other so as to close theopenings 212 to prevent fluid flow therethrough. With the reduction in the axial length of thetubular member 200 from the position ofFigure 15 to the position ofFigure 16 , the concavity of theouter surface 210 of thetubular member 200 increases and the side surfaces 505 and 507 come to have the circumferential extent to which they are spaced increase such that theopenings 212 become of increased cross-sectional area. Thus, whereas inFigure 16 a passage is formed through each opening 212 of a given cross-sectional area, inFigure 15 , the cross-sectional through any passage is reduced to zero as best seen inFigure 17 in cross-section. - The second embodiment illustrated in
Figures 15 to 17 may be manufactured in a number of ways. As one method, the wall of thetubular member 200 could be made initially without anyopenings 212 therethrough, and thereafter axially extending slits may be cut through the wall at each place where anopening 212 is desired. Each slit that is cut preferably would extend in a flat plane which includes acentral axis 22 and extends radially outwardly therefrom through the wall. Where the slits are cut in an unbiased condition of thetubular member 200, theopenings 212 would be closed. Adopting thepump piston 16 with an arrangement in which thepump piston 16 is in an unbiased condition when thetubular member 200 is in an unbiased condition or a stretched condition would result in the openings being closed when the pump piston is in the unbiased condition. - Reference is made to
Figure 18 which shows a fourth embodiment of a piston pump in accordance with the present invention. The fourth embodiment ofFigure 18 is substantially identical to the first embodiment ofFigure 2 with a first exception that the head stem 30 of thevalve piston member 15 of the first embodiment has been removed and is replaced by a hookingmember 34 carried on the annularouter end 204 of thetubular member 200. The hookingmember 34 is arrow head shaped and has axially inwardly directed catchingsurfaces 35 which extend both radially outwardly on an outer prong 160 and radially inwardly on an inner prong 161. - As seen in
Figure 18 , annularly about the opening of thebase portion 49, two hook members are provided as firstly an annular axially inwardly extendingresilient finger member 164 with a distal end which extends radially inwardly to provide an axially outwardly directed catch surface to engage the catchingsurface 35 of the outer prong 160 and secondly an annular axially inwardly extendingresilient finger member 166 with a distal end which extends radially outwardly to provide an axially outwardly directed catch surface to engage the catchingsurface 35 of the inner prong 161. Engagement between the hookingmember 34 and thefinger members tubular portion 200 of thevalve piston member 15 to thebase portion 49 in a snap fit relation against axial removal. - The hooking
member 34 has angled camming surfaces on each radially inward and radially outward side outwardly of the catching surfaces to urge thefingers fingers - Operation of the embodiment illustrated in
Figure 18 is the same as the embodiment inFigure 1 . Since theouter end 204 of thetubular member 200 comprising an annular ring extending circumferentially 360 degrees, theouter end 204 is of assistance in maintaining thetubular portion 200 and thehead portion 47 disposed coaxially about theaxis 22 within the chamber. Preferably, in an embodiment as illustrated inFigure 18 and in the other embodiments, thetubular member 200 is symmetrical about thecentral axis 22 such that with axial compression and expansion of theresilient tubular member 200, the tubular member has an inherent bias to maintain itself coaxially disposed about thecentral axis 22 which, particularly with the embodiment ofFigure 18 , can avoid the need for other coaxial locating devices such as the head stem which in the other embodiments serves to assist in coaxially locating thehead portion 47 coaxially slidable relative to thebase portion 49. - Reference is made to
Figure 19 which shows a fourth embodiment of apump assembly 10 in cross-section which uses apump piston 16 with avalve piston member 15 with ahead portion 47 as in the second embodiment inFigures 15 to 17 in which theopenings 212 through thetubular members 200 close. InFigure 19 , in a manner identical to the embodiment ofFigure 18 , theouter end 204 of thetubular member 200 carries a hookingmember 34 adapted to engage in a hook member carried on thebase portion 49 at an inner end of the base portion annularly about the inner opening of thebase passageway 52. - In the embodiment of
Figure 19 . thevalve piston member 15 and itshead portion 47 continue to include a cross shaped head stem 30 similar to that shown in the first embodiment, however, which head stem 30 does not carry the hookingmembers 34. In the embodiment ofFigure 19 , thepump piston 16 is illustrated as being withinbody 12 attached to abottle 26 similar to that shown inFigure 1 attached to abottle 26. In addition, aremovable closure cap 170 is provided which engages thebody 12 in a snap-fit relation as by a radially inwardly extending hook ring on thecap 170 engaging a radially outwardly extending hook ring about anouter end 23 of thechamber wall 20. Thecap 170 engages theengagement flange 62 to stop thebase portion 49 from movement outwardly. Thecap 170 has acenter post 171 which extends into thepassageway 52 of thebase stem 46 to engage an outer end of the head stem 30 in a position that maintains thetubular portion 200 with itsopening 212 closed preventing fluid flow outwardly. Fluid flow outwardly can also be prevented by thecenter post 171 preventing flow out theoutlet 54. In the embodiment ofFigure 19 , theopenings 212 of thetubular member 200 could be formed as by injection molding at the time of forming thetubular member 200. Theseopenings 212 are to be closed on applying thecap 170 by thetubular member 200 being stretched by engagement of thecenter post 171 to have the axial length of thetubular member 200 increased from the inherent unbiased condition. In the embodiment ofFigure 19 , thetubular member 200 could have theopenings 212 open to provide fluid flow when thepiston 16 is in an unbiased inherent condition. On applying thecap 170, the cap urges the head stem 30 inwardly to increase the length of thetubular portion 200 and close theopenings 212. - Reference is made to
Figure 20 which shows a fifth embodiment of the present invention. The fifth embodiment ofFigure 20 is identical to the first embodiment ofFigure 1 with the exception that the head stem 30 shown in the first embodiment to have an X-shape in cross-section is replaced by a tubular head stem 30 in the embodiment ofFigure 20 . The tubular head stem 30 is formed with acylindrical wall 150 and provides ahead stem passageway 152 coaxial therethrough, closed at aninner end 151 and open at anouter end 153. A hookingmember 34 is provided to extend radially outwardly from the exterior surface of thetubular head stem 30 and provide an axially inwardly directed catchingsurface 35 for engaging with thecatch surface 290 on thebase portion 49. One ormore apertures 154 are provided through thewall 150 of the tubular head stem 30 to permit fluid flow from within thechamber 18 into thehead stem passageway 152 through thetubular head stem 30 and hence into thebase stem passageway 52 of the stem of the base portion to theoutlet 54. - Reference is made to
Figure 21 which shows a sixth embodiment of a piston pump in accordance with the present invention. The embodiment ofFigure 21 is substantially the same as the embodiment illustrated inFigure 18 with the exception that thewall 206 of thetubular member 200 when compressed assumes an hourglass shape as seen in side in which theouter surface 210 of the wall is convex. The extent to which theouter surface 210 is convex increases as the axial length of thetubular member 200 decreases. Theopenings 212 through thetubular member 200 are to be provided such that they provide for flow as desired through the wall when thetubular member 200 is compressed. Theopenings 212 can have configurations which, when uncompressed, the openings are closed and, when compressed, the openings are open with increased cross-sectional area. - With an hourglass shape as shown in
Figure 21 , a maximum reduction in the axial length of thetubular member 200 can be a configuration in which theinner surface 208 of thewebs 213 on opposite sides of thetubular member 200 engage, or in versions in which ahead stem 30 is provided, theinner surfaces 208 of thewebs 213 engage the head stem. Similarly, in an embodiment in accordance with the first embodiment where thetubular member 200 expands radially outwardly, a limit on reduction of the axial length of thetubular portion 200 can be a position in which theouter surface 210 of thewebs 213 extend radially outwardly to engage thewall 20 of thechamber 18. - The preferred embodiment in
Figure 1 illustrates theopenings 212 through thewall 206 of thetubular member 200 as being identical openings evenly spaced circumferentially about thecentral axis 22. This is not necessary. Someopenings 212 may be larger thanother openings 212, however, a preferred configuration would be withopenings 212 of comparable size symmetrically arranged relative to thecentral axis 22 to assist in maintaining thetubular member 200 coaxial about thecentral axis 22 with deflection. Insofar as it may be desired to permit thehead disc 48 to tilt relative to thecentral axis 22, it is possible to provideopenings 212 through thetubular member 200 asymmetrically about the axis such that thetubular member 200 will have a tendency when being compressed to adopt a configuration which tends to tilt the head portion to lie disposed at an angle to thecentral axis 22, as can be of assistance to reduce restriction to flow fluids past thehead disc 48. - Reference is made to
Figure 22 which shows a seventh embodiment of apiston pump assembly 10 in accordance with the present invention. The embodiment ofFigure 22 has many similarities to the embodiment illustrated inFigure 1 and similar reference numerals are used to refer to similar elements. Thepump piston 16 continues to be formed from two elements, namely, thevalve piston member 15 and thevalve body 17. Thevalve body 17 is modified over that shown inFigure 1 so as to have thecentral passageway 52 through thevalve body 17 enlarged so as to provide avalve piston chamber 19 opening axially inwardly through theinlet end 58 and ending at an axially inwardly directedchamber shoulder 218. - The
valve piston member 15 inFigure 22 is identical to that shown inFigure 5 , however, of reduced relative size compared to that shown inFigure 1 such that thehead portion 47 and itshead disc 48 are coaxially slidable within thevalve piston chamber 19 with an edge portion of thehead disc 48 to engage an innercylindrical chamber wall 220 of thevalve piston chamber 19 of thevalve body 17 inFigure 22 in the same manner that inFigure 1 the edge portion of thehead disc 48 engages thechamber wall 20 of thechamber 18 in thebody 12. Theouter end 204 of thetubular member 200 forming theintermediate portion 45 engages thechamber shoulder 218 of thevalve body 17. The relative functioning of thevalve piston member 15 in the embodiment ofFigure 22 is substantially the same as is the case in the embodiment ofFigure 1 with, however, the notable exception that the edge portion of thehead disc 48 engages thechamber wall 220 of thevalve body 17 rather than thechamber wall 20 of thebody 12. - As can be seen in
Figure 22 , ahelical coil spring 222 is provided coaxially within thechamber 18 and adapted to bias thevalve body 17 axially outwardly from thechamber 18 as by having an axialouter end 224 of thespring 222 engage thevalve body 17 at an axially inwardly directedshoulder 226 on thevalve body 17 radially outwardly of the opening to thevalve piston chamber 19. Aninner end 228 of thespring 222 is shown to engage a central non-deflecting portion of the one-way inlet valve 14. Thus, the configuration of thepump piston 16 inFigure 22 facilitates the use of theinternal spring 222 to bias thepump piston 16 outwardly, however, such aninternal spring 222 is not necessary. - A preferred configuration and operation of the embodiment of
Figure 22 is now described with reference toFigures 23 ,24 and25 . In each of these Figures, reference P1 identifies a pressure of fluid in thepassageway 52 on an axial upstream side of thehead disc 48 of thehead portion 47 in theinner compartment 111 and reference P2 is a pressure of the fluid in thepassageway 52 on an axial downstream side of thehead disc 48 of thehead portion 47 in theouter compartment 112. A pressure differential across thehead disc 48 of thehead portion 47 is measured as the upstream pressure P1 minus the downstream pressure P2. In one preferred configuration, thetubular member 200 of theintermediate portion 45 acts as a spring member which is deflectable from an unbiased position as shown inFigure 23 to biased positions such as shown inFigures 24 and25 with thetubular member 200 being resilient and having an inherent bias to assume the unbiased position inFigure 23 in which thetubular member 200 extends an axial distance equal to an unbiased length. Thetubular member 200 is deflectable from the unbiased position ofFigure 23 to biased positions such as shown inFigures 24 and25 in which the length of thetubular member 200 is different than the unbiased length inFigure 23 . Thetubular member 200 is deflectable from the unbiased position shown inFigure 23 to a first biased position shown inFigure 24 when the pressure differential across thehead disc 48 is equal to a first pressure level. - The peripheral
circumferential edge portion 48a of thehead disc 48 on thehead portion 47 is elastically deformable between an unbiased condition and biased condition wherein in the unbiased condition, the edge portion engages thechamber wall 220 of thevalve piston chamber 19 to prevent fluid flow therepast and in biased positions, the edge portion elastically deflects away from thechamber wall 220 to permit fluid flow therepast. Preferably, the edge portion of thehead disc 48 assumes it unbiased condition when the pressure differential across thehead disc 48 is less than or equal to the first pressure level. The edge portion of thehead disc 48 assumes biased conditions to permit fluid flow therepast when the pressure differential exceeds the first pressure level. -
Figure 23 illustrates a condition in which the pressure differential is less than the first pressure level.Figure 24 illustrates a condition in which the pressure differential is equal to the first pressure level and, as can be seen, the spring-formingtubular member 200 has been moved from an unbiased position as seen inFigure 23 to assume a biased condition inFigure 24 . InFigure 24 , however, theedge portion 48a of thehead disc 48 continues to engage thechamber wall 220 to prevent fluid flow therebetween. -
Figure 25 illustrates a condition in which the pressure differential exceeds the first pressure level. As can be seen inFigure 25 , theedge portion 48a of thehead disc 48 has been deflected radially inwardly from thechamber wall 220 permitting fluid flow outwardly therepast. InFigure 25 , fluid may flow outwardly past thehead disc 48 through theopenings 212 of thetubular member 200 and out through thepassageway 52 between thearms 32 of thehead stem 30. - In a cycle of operation, from the position of
Figure 23 , on an inward retraction stroke of thepump piston 16, pressure P2 is increased with the increase in pressure P1 deflecting the spring formingtubular member 200 to the position ofFigure 24 as the pressure differential across thehead disc 48 reaches the first pressure level. With continued inward movement of thepump piston 16, the pressure differential continues to increase until the pressure differential exceeds the first pressure level and, as seen inFigure 25 , thehead disc 48 is displaced inwardly from thechamber wall 202 to prevent fluid flow outwardly therepast as seen inFigure 25 . Once the pressure differential across thehead disc 48 may become reduced to being equal to or less than the first pressure level, as may occur if thevalve body 17 may ceased to be moved axially outwardly then, firstly,head disc 48 reverts to an unbiased condition in which it prevents fluid flow outwardly therepast as the pressure differential drops to the first pressure level to adopt a position as shown inFigure 24 and, subsequently, with a further drop in the pressure differential to being less than or equal to the first pressure level, the spring formingtubular member 200 assuming an unbiased position as shown inFigure 23 . In the operation of thepump assembly 10, the of operation with thepump piston 16 being moved axially outwardly in a withdrawal stroke and axially inwardly in a retraction stroke, thevalve piston member 15 will move in a cycle from the position ofFigure 23 to the position ofFigure 24 to the position ofFigure 25 , returning to the position ofFigure 24 and subsequently returning to the position ofFigure 23 . In this cycle of operation, in movement of thevalve piston member 15 from the position ofFigure 24 to the position ofFigure 23 , thehead disc 48 engages thevalve piston chamber 19 to prevent fluid flow therebetween and due to an increase in volume of theouter compartment 112 formed in thevalve piston chamber 19 outwardly of thehead disc 48 fluid is drawn back from thepassageway 52 into thevalve piston chamber 19, This drawback of fluid can be advantageous to prevent fluid in thepassageway 52 at theoutlet 58 from being available to drip under gravity out of thedischarge outlet 54. - Reference is made to
Figure 26 which shows apump piston 16 in accordance with an eighth embodiment of the present invention which is identical to that illustrated inFigure 23 with the exception that thevalve piston chamber 19 has achamber wall 220 which is stepped rather than being merely cylindrical as illustrated inFigure 23 . As can be seen inFigure 26 , thechamber wall 220 includes an axiallyinner portion 230 of a first diameter, an axiallyouter portion 232 of a second diameter joined by anintermediate transition portion 231 which is shown to be frustoconical. In the embodiment ofFigure 26 , as the pressure differential across thehead disc 48 increases and the spring formingtubular member 200 is compressed and reduces in axial length from an unbiased position to biased positions, fluid flow is permitted to occur past thehead disc 48 by either one or both of: (1) deflection of the edge portion of thehead disc 48 when the pressure differential exceeds the first pressure level and (2) axial movement of thehead portion 47 with deflection of thetubular member 200 such that thehead disc 48 is displaced axially outwardly to a location within thetransition portion 231 or axiallyouter portion 232 where the radial extent of thechamber wall 220 is greater than the radial extent of thehead disc 48. Otherwise, operation of a piston pump assembly utilizing thepump piston 16 shown inFigure 26 is the same as that discussed with respect to the embodiment ofFigure 22 . - Reference is made to
Figure 27 which shows a ninth embodiment of apump piston 16 identical to that shown inFigure 26 but for the modification of thechamber wall 220 to show thetransition portion 231 as being formed as a radially extending axially outwardly directed shoulder, and to replace thehead disc 48, as seen inFigure 26 , with a modifiedhead disc 48 having a substantially increased axial dimension such that thehead disc 48, as shown inFigure 27 , has significantly reduced tendencies to have its edge portion deflect out of engagement with thechamber wall 220 over theinner portion 230. In the embodiment ofFigure 27 , with deflection of the spring formingtubular member 200 to be compressed, fluid is permitted to flow axially past thehead disc 48 dominantly by thehead disc 48 coming to be moved axially into the enlarged diameterouter portion 232 of thechamber wall 220 where the diameter is greater than the diameter of thehead disc 48. - Reference is made to
Figures 28 and 29 which show a tenth embodiment of apump piston 16 in accordance with the present invention which has considerable similarities to the embodiment illustrated inFigure 23 . However, inFigure 28 , thetubular member 200 has been eliminated and replaced by ahelical coil spring 334 which has an outer end 335 engaging thechamber shoulder 226 and aninner end 336 engage an axially outwardly directed surface 337 of thehead portion 47 such that thespring 334 biases thehead portion 47 axially inwardly to a position axially limited by the hookingmember 34 engaging the outwardly directedcatch surface 290. - Preferably, the relative resiliency of the
spring 334 and the edge portion of thehead disc 48 can be selected so as to permit the operation of the embodiment ofFigure 28 to be the same as the embodiment ofFigure 22 . However,Figure 28 also shows an optional modification of thechamber wall 220 so as to provide three circumferentially spaced axially extending radially inwardly directed spacingribs 240 disposed in theouter portion 232 of thevalve piston chamber 19. As thespring 234 is compressed due to increasing pressure differential across thehead disc 48, the deflection of theedge portion 48a of thehead disc 48 radially inwardly to permit fluid flow therepast is provided by either or both of (1) the resilient deflection of the edge portion due to the increased pressure differential there across, and (2) theedge portion 48a of thehead disc 48 on moving axially engaging thespacing ribs 240 which deflect the edge portion of thehead disc 48 away from thechamber wall 220 permitting fluid flow therepast. - The
spacing ribs 240 can best be seen in the cross-section through thevalve body 17 as seen inFigure 29 . Thespacing ribs 240 are spaced axially outwardly from the location of thehead disc 48 in the position as shown inFigure 28 such that thehead disc 48 can be moved axially inwardly of thespacing ribs 240 for an axial distance in engagement with thechamber 220 which provides for suitable fluid drawback in operation. - In each of the embodiments illustrated in
Figures 22 to 29 , thevalve piston member 15 has included a spring-formingcomponent - Reference is made to
Figures 30 to 33 which together with the embodiments ofFigures 36 to 39 show arrangements in which thevalve piston member 15 includes a spring-forming component which is axially stretched to increase in axial length as the pressure differential increases. - Reference is made to
Figure 30 which illustrates apump piston 16 in accordance with an eleventh embodiment of the present invention having considerable similarities to the pump piston shown inFigure 23 , InFigure 30 , thevalve piston member 15 is modified over thevalve piston member 15 shown inFigure 23 so as to conceptually remove thetubular member 200 from its position as illustrated inFigure 23 and locate thetubular member 200 such that it extends axially inwardly from thehead portion 47 to a distal end carrying the radially outwardly extendinghook members 34 to engage on the axially inwardly directedshoulder 226 at the axialinner end 224 of thevalve piston chamber 19. As seen inFigure 30 , thetubular member 200 is shown to be the same as inFigure 5 but inverted and secured to an inner end of thehead portion 47. -
Figure 30 shows thetubular member 200 in an unbiased condition. On increase of the pressure differential across thehead disc 48, the resilient spring formingtubular member 200 is expanded and thehead portion 47 is thus moved axially inwardly until the pressure differential is increased sufficiently that the edge portion of thehead disc 48 deflects from thechamber wall 220 permitting fluid flow axially therepast. Once the pressure differential across thehead disc 48 is reduced, thetubular member 200 returns from a biased extended condition to an unbiased retracted position drawing thehead portion 47 axially inwardly. Fluid flow is permitted axially through thetubular member 200 via itsopening 212. - Reference is made to
Figure 31 which shows a twelfth embodiment of apump piston 16 in accordance with the present invention which is substantially the same as the embodiment illustrated inFigure 31 but for three notable exceptions. Firstly, inFigure 31 , thechamber wall 220 has a stepped configuration withinner portion 230,transition portion 231 andouter portion 232 similar to that illustrated inFigure 26 rather than being merely cylindrical as inFigure 30 . Secondly, the spring formingtubular member 200 has a side wall in the form of a relative S shape rather than merely being at shape as seen inFigure 30 . Thirdly, theannular catch member 34 provided at the axialtv inner end of thetubular member 200 extends radially outwardly and then axially inwardly so as to provide an axially inwardly directedannular groove 242 adapted to receive theouter end 224 of theinternal coil spring 222 as can be of assistance in maintaining the axiallyinner end 224 of thetubular member 200 coupled to the axiallyinner end shoulder 226 of thevalve body 17. - Reference is made to
Figure 32 which shows a thirteenth embodiment of apump piston 16 in accordance with the present invention. In the embodiment ofFigure 32 , thevalve body 17 is illustrated as being formed from two elements, an axiallyouter portion 230 and an axiallyinner portion 232 which are secured together as in a snap-fit relation to jointly form thevalve piston chamber 19 with thechamber wall 220 having a stepped configuration similar to that shown inFigure 31 . Theinner portion 232 has asupport plate 234 which extends across the axial inner end of thevalve piston chamber 19 presentingopenings 236 for fluid flow axially therethrough and also acentral opening 238. Thevalve piston member 15 comprises ahead portion 47 carrying ahead disc 48 and a variable lengthintermediate portion 45. An axiallyouter end 240 of the variable lengthintermediate portion 45 is coupled to thehead portion 47. The axiallyinner end 242 of the variable lengthintermediate portion 45 carries anenlarged catch button 244 with an axially outwardly directedcatch surface 246 to engage thesupport plate 234 and prevent axial outward movement of theinner end 242 of the variable lengthintermediate portion 45. Theintermediate portion 45 is resilient and adapted to elastically deform from an unbiased position as shown inFigure 32 to extend in axial length as the pressure differential across thehead disc 48 increases and to return from biased positions to the unbiased position shown inFigure 32 . As the pressure differential across thehead disc 48 increases, theintermediate portion 45 is stretched and expands to increase in axial length such that with sufficient pressure differential increase, thehead portion 47 carrying thehead disc 48 is moved axially outwardly until fluid is permitted to flow axially outwardly therepast as by thehead disc 48 coming to become axially located in the enlarged diameterouter portion 232 of thechamber wall 220 and/or by radially inward deflection of thehead disc 48, - The embodiment illustrated in
Figure 32 can be configured having regard to the relative resiliency and ability of theintermediate portion 45 to expand under increased pressure differential so as to provide operation substantially the same as that illustrated inFigure 30 and analogous to that inFigure 23 . The embodiment illustrated inFigure 32 preferably provides thevalve piston member 15 to be injection molded as a single element from suitably resilient material with the relevant radial cross-section area of theintermediate portion 45 and its axial extent selected to provide suitable resiliency and deflection under different pressures and the relative ability of thehead disc 48 to have its edge portion deflect radially inwardly being also suitably selected. - Reference is made to
Figure 33 which shows a fourteenth embodiment in accordance with the present invention which has similarities to the embodiment illustrated inFigure 32 , however, inFigure 33 , thevalve piston member 15 includes ahelical coil spring 250 as the variable lengthintermediate portion 45 whichhelical coil spring 250 biases thehead portion 47 axially inwardly to an unbiased position. As shown inFigure 33 , the coil spring has an axiallyouter end 251 engage an axially inwardly directedsurface 252 of thesupport plate 234 and an axiallyinner end 254 engage an axially outwardly directedsurface 256 of thecatch button 244. In the embodiment illustrated inFigure 33 , the element forming thehead portion 47 includes an inwardly extendingstem 258 ending at thecatch button 244. Thishead portion 47 need not have any substantial resiliency to axial deflection. - Reference is made to
Figures 34 and35 which illustrate a fifteenth embodiment in accordance with the present invention adopting a configuration for thepump piston 16 having many similarities to that shown in the embodiment ofFigure 22 , however, in which thevalve body 17 is, as contrasted with the unitary element shown inFigure 22 , includes two elements, namely, a sealingmember 740 and avalve seat member 742. The sealingmember 740 carries theannular base disc 50. The sealingmember 740 is adapted to sealably engage adischarge tube 716. Thevalve seat member 742 carries the checkvalve piston chamber 19 and thevalve piston member 15 which are substantially identical to that illustrated inFigure 22 .Figure 34 illustrates apump mechanism 10 with an upwardlyopen bottle 26 having a downwardly extendingdip tube 711 and shows acheck valve member 15 operable in a manner the same as that disclosed inFigure 22 to provide for drawback from thedischarge outlet 54 of thedischarge tube 716. -
Figures 33 and34 show afluid dispenser 10 in accordance with the present invention having aremovable bottle 26 and apump assembly 10 having similarities to a fluid dispenser disclosed in U.S. Patent PublicationUS 2008/0112830 to Ophardt et al, published May 15, 2008 , the disclosure of which is incorporated herein by reference. -
Figure 34 shows thepump assembly 10 comprising apump piston 16 and a pistonchamber forming body 12 disposed relative areservoir bottle 26 for dispensing fluid from thebottle 26. Thepiston body 12 includes ametal cylinder 715 forming thechamber 18 therein, the inner one-way check valve 14 secured in theinner end 727 of thechamber 18 and ahollow dip tube 711 extending downwardly from theinner end 727 of thechamber 18. - The
pump piston 16 includes ametal tube 716, acasing member 722, the plasticannular sealing member 740 and thecheck valve member 15. - A
helical coil spring 772 is disposed in thechamber 18 between theinner check valve 14 and thecheck valve member 15 to bias thepump piston 16 axially outwardly of thechamber 18. - The
inner check valve 14 provides for one-way flow outwardly therepast but preventing flow inwardly therepast. - As with the other embodiments, the
check valve member 15 is configured to function to permit fluid flow outwardly therepast, that is, in a downstream direction, under certain conditions, as when the pressure of fluid on a upstream side of thecheck valve member 15 is greater than the pressure of fluid on a downstream side of thecheck valve member 15, and to prevent fluid flow inwardly therepast, that is, in an upstream direction, other than under certain conditions in which thecheck valve member 15 operates to draw some fluid back past it in a upstream direction. - The
pump piston 16 includes themetal tube 716 having a vertical portion 718, acurved portion 719 and ahorizontal portion 720 ending at a downwardly directeddischarge outlet 54. Thepump piston 16 includes thecasing member 722 about the upper end of the vertical portion 718 of the tube and thecurved portion 719. Thecasing member 722 has a locatingportion 723 with external cylindrical guide surfaces 724 to guide the upper end of the vertical portion 718 of thetube 716 coaxially within the piston chamber forming member 714. - The
body 12 is preferably formed from metal and has ametal cylinder 715 defining therein thecylindrical chamber 18 about acentral axis 22. Thechamber 18 has a chamber wall with aninner surface 20. Thechamber 18 is open at an upper, outer end and open at a lower, inner end. Thehollow dip tube 711 extends downwardly from the inner end of thechamber 18 to aninlet end 717 in communication with thereservoir bottle 26. - The
pump piston 16 includes aninner portion 737 at a lower end of thetube 716 where the plasticannular sealing member 740 is fixedly secured to thetube 716. The sealingmember 740 is secured to the lower end of thetube 716 and provides acentral bore 742 therethrough for fluid flow from a lower inner end of the sealingmember 740 through the sealingmember 740 and into the openlower end 738 of thetube 716. The sealingmember 740 includes (a) an axially upwardly directedsocket 744 for fixed, sealed engagement with thelower end 738 oftube 716, (b) a locating ring 746 for slidably locating the sealing member coaxially within thechamber 18, and (c) anannular base disc 50 to engage the inner surface of thechamber wall 20 forming a substantially fluid impermeable seal therewith on sliding of thepump piston 16 inwardly and outwardly. Thebore 742 extends through the sealingmember 740 centrally through thesocket 744, the annular locating ring 746 and anannular base disc 50. - A lower end of the
tube 716 is frictionally and sealably received inside the cylindrical inner side wall 754 of thesocket 744 abutting on the shoulder 756. - The
pump assembly 10 has axially inward of the sealingmember 740 theouter check valve 15 and theinner check valve 14. - The
inner check valve 14 provides for one-way flow outwardly therepast but preventing flow inwardly therepast. An innervalve seat member 791 of theinner check valve 14 is fixedly secured in the inner end of thecylinder 715. Thedip tube 711 is shown as an integral extension of the innervalve seat member 791, Aball cage member 793 is engaged above, outwardly of the innervalve seat member 791, and serves to retain aball 794 above the innervalve seat member 791 yet permits fluid flow centrally therethrough. - The
helical coil spring 772 has an inner end engage theball cage member 793 urging it inwardly into the innervalve seat member 791, An outer end of thespring 772 engages on anannular valve body 17 of the outer valve resiliently resisting inward, downward movement of thevalve body 17. - The
valve body 17 is slidable in thechamber 18 and biased axially upwardly and outwardly into engagement with the sealingmember 740 by thecoil spring 772. - As seen in
Figure 34 , thevalve body 17 has at its radially outermost surface at its upper outer end, an inner end as acam shoulder 782 which is angled to extend radially outwardly and axially inwardly for engagement with aninner end 784 of the sealingmember 40. - Movement of the
pump piston 16 axially inwardly to a retracted position relative thebody 12 urges the sealingmember 740 into thecheck valve member 15 compressing thespring 772. On release of thepump piston 16, thespring 772 biases thepump piston 16 to return to an extended position. Reciprocal movement of thepump piston 16 draws fluid from thereservoir 26 in the inner end of thedip tube 711 through thedip tube 711, through the inner end of thechamber 18 through thetube 716 and dispenses fluid out thedischarge outlet 54 of thetube 716. - Reference is made to
Figures 36 and37 which illustrate a sixteenth embodiment in accordance with the present invention representing a side view through a portion of a piston pump substantially the same as shown inFigure 35 , however, with a modified form of thevalve seat member 742 andvalve piston member 15. As with the embodiment inFigure 35 , acoil spring 222 biases thevalve seat member 742 axially outwardly into engagement with the sealingmember 740 which carries thebase disc 50. Thevalve seat member 742 provides thevalve piston chamber 19 coaxially therein having a steppedchamber wall 220. Thevalve seat member 742 has acentral passageway 52 therethrough and provides at an axiallyinner end 58 of thevalve piston chamber 19 an axially inwardly directedannular shoulder 226 to be engaged by the axially outer end of thecoil spring 222. Thevalve piston member 15 includes ahead portion 47 carrying thehead disc 48 with anannular edge portion 48a adapted to engage thechamber wall 220. Thehead portion 47 is shown to be coupled to a variable lengthintermediate portion 45 which includes a central stem and an enlargedhead catch button 244.Radially extending openings 236 are provided through thevalve seat member 742 axially outwardly of theshoulder 226 via which fluid may flow radially outwardly of theintermediate portion 45 into thevalve piston chamber 19 axially inwardly of thehead disc 48. - The
intermediate portion 45 preferably has its central stem to be formed of resilient material such that a pressure differential across thehead disc 48 causes theintermediate portion 45 to stretch axially outwardly as to permit thehead disc 48 to become received within the enlarged diameterouter portion 232 of thevalve piston chamber 19 such that fluid may flow outwardly therepast. In addition to providing the central stem of theintermediate portion 45 to be resilient and to act as a spring, thecatch button 244 is provided to also act as a coned-disc spring or Belleville washer by comprising adisc 247 which extends from the stem with an annular profile tapering radially outwardly and axially outwardly to a radiallyouter edge 245.Figure 36 illustrates an unbiased condition of thecheck valve member 15 andFigure 37 illustrates a biased condition of thecheck valve 15 in which the pressure differential across thehead disc 48 is sufficient that theintermediate portion 45 is deflected and increased in length axially outwardly, thedisc 247 of thecatch button 244 has become flattened to move the stem axially outwardly and thehead disc 45 has become moved axially outwardly to be received within the enlarged diameter outer portion such that fluid can pass outwardly therepast. - It is to be appreciated that one or both of the resilient flexing of the coned-disc sping-forming
disc 247 of thecatch button 244 and the resilient stretching of the central stem may provide suitable resiliency to theintermediate length portion 47 to extend axially inwardly under pressure differentials across thehead disc 48 as may be desired. - Reference is made to
Figures 38 and39 illustrating a seventeenth embodiment in accordance with the present invention. As with the other embodiments, thepump assembly 10 ofFigure 38 provides abody 12 secured to a collapsible container and with apump piston 16 slidable relative to thebody 12 so as to discharge fluid out of anoutlet 54. The embodiment ofFigure 38 utilizes avalve piston member 15 within avalve body 17 providing thevalve piston chamber 19 and having similarities to the valve piston member and valve body as disclosed in the embodiments ofFigures 22 to 37 . However, in the embodiments ofFigures 23 to 37 , thevalve piston member 15, thevalve body 17 and thevalve piston chamber 19 are disposed coaxially about theaxis 22 with respect to which thepump piston 16 is coaxially slidable relative to thechamber 18 andbody 12. However, as illustrated in the embodiment ofFigure 38 , this is not necessary that a pump configuration have thevalve body 17 provide thevalve piston chamber 19 that thevalve piston chamber 19 be disposed coaxially about theaxis 22. Rather, thevalve piston chamber 19 may be disposed at a different orientation and the embodiment ofFigure 39 shows an orientation in which thevalve piston chamber 19 is disposed about avalve axis 822 perpendicular to theaxis 22 that thepump piston 16 is coaxially slidable relative to thebody 12. - In
Figure 38 , thebody 12 includes an outer cylindrical tube 824, an intermediatecylindrical tube 826 and an innercylindrical tube 828, The outer cylindrical tube 824 has its interior surface threaded such that the outer cylindrical tube 824 forms a threaded collar for threadable engagement on theneck 34 of thecollapsibte container 26 so as to form a seal therewith. Anouter shoulder 825 connects an outer end of the outer tube 824 with theintermediate tube 826. Aninner shoulder 827 connects an inner end of the intermediate tube 824 with an inner end of theinner tube 828. Abridge plate 830 is provided extending radially across theinner tube 228 to support the one-way valve 14 with a resilientannular ring 132 of the one-way valve 14 in engagement with radially inner annular surfaces of the inner tube. - The
pump piston 16 comprises three elements, namely, acasing 832, thevalve piston member 15 and thedischarge tube 716. - The
casing 832 is preferably formed as an integral member injection moulded from plastic and providing acylindrical piston tube 834 coaxially disposed about theaxis 22 and providing a radially outwardly directedpiston surface 836 sized so as to be coaxially slidable within theintermediate tube 826 of thebody 12 with thepiston surface 836 in sealed engagement with theannular chamber wall 20 to prevent fluid flow therebetween. Thecasing 832 also provides anoutlet tube 838 which is disposed about theaxis 822 normal to theaxis 22. Via thecasing 832, an axially outer end of theintermediate tube 826 communicates with an inner end of theoutlet tube 838. Theouter end 840 of theoutlet tube 838 provides a socket to receive theinner end 842 of thedischarge tube 716 in a snap-fit relation. Thevalve piston chamber 19 is defined in theoutlet tube 838 inwardly from aninner end 844 of thedischarge tube 716 and outwardly of asupport plate 234 formed as part of thecasing 832 extending across theoutlet tube 838 and providingopenings 236 for fluid flow therethrough as well as acentral opening 238. Thevalve piston member 15 has a configuration similar to that shown inFigure 32 with an axially inner end of the variable length intermediate portion carrying anenlarged catch button 224 which engages thesupport plate 234 to prevent axial outward movement of an inner end of the variable lengthintermediate portion 45. Theintermediate portion 45 has its stem pass through thecentral opening 238 of thesupport plate 234. Theintermediate portion 45 is resilient and adapted to elastically deform by stretching in a downstream direction. Thevalve piston member 15 comprises ahead portion 47 carrying ahead disc 48, Thehead disc 48 is disposed within thevalve piston chamber 19, Thevalve piston chamber 19 has achamber wall 220 with a stepped configuration similar to that shown inFigure 32 . Operation of the valve piston member is in thevalve piston chamber 19 is the same as that described with reference toFigure 32 such that as the pressure differential across the head disc increases, theintermediate portion 45 is stretched and expands or increases in axial length such that with sufficient pressure differential, thehead disc 48 is moved axially outwardly until fluid is permitted to flow axially therepast as by the head disc coming to become axially located in the larger diameterouter portion 232 of thechamber wall 220 and/or by radially inward deflection of thehead disc 48. The casing and its discharge tube effectively forms thevalve body 17 about thevalve piston member 15. - For assembly, the
valve piston member 15 may be inserted through the outlet end of the discharge tube socket and thereafter thedischarge tube 720 may be inserted into the socket. -
Figures 40 and41 illustrate an eighteenth embodiment in accordance with the present invention.Figure 40 is a view similar toFigure 39 but showing the entirety of acasing 832. - In
Figure 40 , thecasing 832 is substantially identical to the casing shown inFigure 39 with the exception that thesupport plate 234 has merely theopenings 236 therethrough for fluid flow but not acentral opening 232 as seen inFigure 39 . Thedischarge tube 716 inFigure 40 is similar to that shown inFigure 39 . Thedischarge tube 716 has an axially inwardly directedshoulder 840. At circumferentially spaced locations, axially extending channelways 842 are provided in the interior side wall of thedischarge tube 716 extending axially inwardly from the shoulder. - The
piston valve member 15 is shown in cross-section inFigure 40 and in a pictorial view inFigure 41 . Thehead portion 47 carries ahead disc 48 and itsedge portion 48a. Thehead portion 47 also carries at its axially inner end alocating disc 844 which serves the purpose of coaxially locating thevalve piston member 15 within thevalve piston chamber 19 proximate the axial outward side of thesupport plate 234 with an axially inwardly directedsurface 846 of thehead portion 47 in engagement with an axially outwardly directed surface of thesupport plate 234. Thelocating disc 844 hasslots 848 cut therethrough at circumferentially spaced locations so as to constantly maintain communication through thesupport plate 234 via theopenings 236 and theslots 848 into thevalve piston chamber 19 upstream of thehead disc 48. Theinner end 842 of thedischarge tube 716 is received in the outer end of theoutlet tube 834 in a manner to provide a fluid seal therebetween and to prevent fluid flow therebetween. - The
valve piston member 15 includes as a variable length intermediate portion 45 atubular member 200 which is illustrated to have anannular wall 857 which reduces in thickness from anouter end 849 of thevalve piston member 15 towards thehead disc 48. Thetubular member 200 has a radially outwardly directed surface including a taperedsurface portion 850 which tapers to reduce in diameter towards thehead disc 48 and acylindrical portion 851. In the radially outwardly directedexterior surface tubular member 200, a plurality of circumferentially spaced axially extending radially inwardly extending channelways 852 are provided. As can be best seen inFigure 40 , at all times, at least one of thechannelways 852 of thetubular member 200 circumferentially align with at least one of thechannelways 842 in the interior side wall of thedischarge tube 716 such that at all times communication is provided from thevalve piston chamber 19 downstream of thehead disc 48 to the interior of thedischarge tube 716. Thepiston valve member 15 illustrated inFigures 40 and41 is preferably resilient as, for example, formed from resilient material such as silicon. Preferred materials for this and the other embodiments is a silicon having a resiliency and hardness as measured using Shore Durometer Hardness Testing for plastics in the range ofShore A 40 to 60 and, more preferably,Shore A 50. - The
piston valve member 15 can be seen to become engaged axially against movement between thesupport plate 234 and theshoulder 840 of thedischarge tube 716. With increases of the pressure differential across thehead disc 48 as by the pressure P1 upstream of thehead disc 48 becoming greater than the pressure P2 downstream of thehead disc 48, the pressure differential will, as in the manner of the other embodiments, act to reduce the length of thetubular portion 200 permitting thehead disc 48 to slide axially in thevalve piston chamber 19 into enlarged diameter portions within thevalve piston chamber 19 which, together with radial inward deflection of thehead disc 48, permits fluid flow outwardly past thehead disc 48. In a preferred configuration, when the pressure differential reduces, then thehead disc 48 preferably to provide drawback will under its resiliency deflect radially outward into sealed engagement with the annular side wall of thevalve body 17 to form a seal therewith before the length of thetubular portion 200 has increased to return thehead disc 48 into engagement with thesupport plate 234. - As can be seen in
Figures 40 and41 , thetubular member 200 has a central blind bore 856 extending coaxially therein open axially outwardly to provide thetubular member 200 with acylindrical wall 857. Thetubular member 200 is axially deflectable as with itstubular wall 857 to bow radially outwardly as thetubular member 200 is compressed axially. As can also be seen inFigures 40 and41 , anannular groove 858 is provided between thetubular member 200 and thehead disc 48 open axially outwardly such that the head disc in the preferred embodiment is a frustoconical tubular member adapted to be deflected radially inwardly. - Reference is made to
Figures 45 and46 which shows an embodiment identical to that inFigures 40 and41 , respectively, however, in which theannular groove 858 between thehead disc 48 and thetubular member 200 as seen inFigures 40 and41 , has been eliminated such that thehead disc 48 is solid and merges radially into thetubular member 200. In the embodiment ofFigures 45 and46 , the inherent resiliency of the material forming thehead disc 48 can provide the desired deflection and inherent bias to thehead disc 48. The resiliency of thehead disc 48 can be adjusted either by increasing the relative size of theannular groove 858 in the embodiment ofFigures 40 and41 or by adjusting the resiliency of the material forming thevalve piston member 15 as in the embodiment ofFigures 45 and46 . To the extent that thehead disc 48 is provided to be less resilient and, for example, substantially rigid, then this will tend to reduce the extent to which drawback is provided and, similarly, the extent to which thehead disc 48 is flexible and resilient can increase the extent to which relative drawback may be provided. - Reference is made to
Figure 47 which illustrates a further embodiment identical to the embodiment ofFigure 40 , however, in which the only opening for flow through thesupport 234 is acentral opening 232 which is closed to fluid flow therebetween by the axially inwardly directedsurface 846 on the axialinner end 860 of thehead portion 47 of thevalve piston member 15 sealably engaging the axially outwardly directed surface of thesupport plate 234. In this embodiment, the pressure P1 must be sufficiently great to compress thevalve piston member 15 axially by compressing thetubular member 200 before the pressure P1 comes to be applied into thevalve piston chamber 19 and onto thehead disc 48. - Reference is made to
Figure 42 which illustrates a nineteenth embodiment of avalve piston member 15 in accordance with the present invention and having alocating disc 844 and ahead portion 47 with ahead disc 48 substantially the same as that illustrated inFigure 41 , however, in which the resilientintermediate portion 45 comprises an integrally formed spring member formed from resilient material and having a plurality ofopposed legs 854 each of which forms a U-shaped spring adapted to resiliently deflect about a livingspring hinge 856 and revise to return to an unbiased position. The spring member is connected at an axially inner end to thehead portion 47 at an axially outer end to alocating disc 850 with acentral opening 860 therethrough for passage of fluid. Thevalve piston member 15 ofFigure 42 is adapted to be substituted for the valve piston member inFigure 10 and provide for operation in an analogous manner. - Reference is made to
Figure 43 which shows a thin member in accordance with a twentieth embodiment of the invention. -
Figure 43 illustrates an embodiment which is identical to the embodiment ofFigure 2 in respect of the resilientintermediate portion 45, however, in which thehead portion 47 has been substituted by a thin disc of resilient material shown to be substantially circular and perpendicular to an access through thevalve piston member 15 and provided withresilient edge portion 48a. Thevalve piston member 15 may be used in the embodiment ofFigure 40 in substitution of thevalve piston member 15 shown therein. - Reference is made to
Figure 44 which shows a twenty-first embodiment of avalve piston member 15 in accordance with the present invention with a modified form of the valve piston member ofFigure 43 having a similar portion as acircular disc 48 and in which the resilientintermediate portion 45 is illustrated as comprising an open web ofresilient arms 862 interconnected at various locations to forminterstitial spaces 884 and extending downwardly to threeend support apex 860. The valve piston member ofFigure 44 is also adapted for replacement of thevalve piston member 15 inFigure 40 . The open matrix of arcuateresilient beams 882 resists axial compression of thevalve piston member 15 and biases the valve piston member to assume an unbiased length as shown inFigure 44 . - In the embodiments of
Figures 43 and44 with circular discs, merely the deflection of theedge portion 48 of the disc may be sufficient to permit fluid flow therepast without the need for the circular disc to become engaged in an enlarged diameter portion of thevalve piston chamber 19. Operation of thevalve piston member 15 inFigures 43 and44 is preferably the same as indicated with other embodiments with the resilient intermediate portion deflecting axially prior to thehead disc 48 permitting fluid flow axially therepast. - While the invention has been described with reference to preferred embodiments, many modifications and variations will now occur to persons skilled in the art. For a definition of the invention, reference is made to the following claims.
Claims (15)
- In combination, a tube member and a valve member:the tube member having a tube inner wall defining therein an axially extending fluid passageway for flow of a fluid in an axial downstream direction therethrough,the tube inner wall having a tube upstream portion and a tube downstream portion, the tube downstream portion located in the downstream direction from the tube upstream portion,the valve member disposed within the passageway,the valve member comprising a spring member and a piston head member,the spring member having a spring first end and a spring second end, the spring member extending axially within the passageway from the spring first end to the spring second end,the spring first end coupled to the tube inner wall at a first location against relative axial movement with the tube member,the piston head member fixedly secured to the spring second end, the spring member being resilient and having an inherent bias to assume an unbiased position in which the spring second end is axially spaced from the spring first end by a distance equal to an unbiased length,the spring member deflectable from the unbiased position to biased positions in which the spring second end is axially spaced from the spring first end by distances different than the unbiased length,in moving from the unbiased position to the biased positions the spring second end is moved in the axial downstream direction relative the spring first end,the piston head member having an axial downstream side and an axial upstream side,a pressure differential across the piston head member is measured as a pressure of the fluid in the passageway on the axial upstream side of the piston head member minus a pressure of the fluid in the passageway on the axial downstream side of the piston head member.
- A combination as claimed in claim 1 wherein the piston head member having a peripheral circumferential edge portion wherein when the edge portion of the piston head member is in the tube upstream portion engagement between the edge portion and the tube inner wall of the tube upstream portion prevents fluid flow axially therebetween, and when the edge portion of the piston head member is in the tube downstream portion interaction between the edge portion of the piston head member and the tube downstream portion permits fluid flow downstream therepast,
wherein when the pressure differential is less than or equal to a first pressure level the edge portion of the piston head member is in the tube upstream portion and when the pressure differential is greater than the first pressure level the edge portion of the piston head member is in the tube downstream portion. - A combination as claimed in claim 2 wherein the tube upstream portion being circular in cross section normal to the axis, the tube upstream portion having a diameter,
the tube downstream portion being circular in cross-section normal to the axis, the tube downstream portion having a diameter greater than the diameter of the tube upstream portion. - A combination as claimed in claim 3 wherein the edge portion of the piston head member is circular in cross-section normal to the axis,
the edge portion having a diameter less than the diameter of the tube upstream portion. - A combination as claimed in claim 2, 3 or 4 wherein the edge portion of the piston head member is elastically deformable between an unbiased condition and biased conditions wherein in the unbiased condition the edge portion engages the tube inner wall to prevent fluid flow therepast and in the biased conditions the edge portion elastically deflects away the tube inner wall to permit fluid flow therepast.
- A combination as claimed in claim 5 wherein the edge portion of the piston head member is elastically deformable from the unbiased condition toward biased conditions, however, provided that the pressure differential is less than or equal to the first pressure level while the edge portion is in the tube first portion the edge portion prevents fluid flow in the passageway in either direction therepast.
- A combination as claimed in claim 5 or 6 wherein the edge portion of the piston head member is elastically deformable from the unbiased condition toward biased positions, however, provided that the pressure differential is greater than the first pressure level while the edge portion is in the tube second portion the edge portion permits fluid flow in the passageway in the downstream direction therepast.
- A combination as claimed in any one of claims 2 to 7 wherein the tube member is a discharge tube member leading to a discharge outlet from which fluid is dispensed.
- A combination as claimed in claim 8 wherein in operation after discharging the fluid through the tube member past the valve member and out the discharge outlet under a pressure differential greater than the first pressure level, on a decrease in the pressure differential from the first pressure level to pressure differentials which are less than the first pressure level, the spring member deflects under its inherent bias moving the spring second end in an upstream direction from the first of the biased positions towards the unbiased position, with the edge portion of the piston head member moving with the spring second end while engaging the tube inner wall to prevent fluid flow therepast, whereby fluid in the tube member at the discharge outlet is drawn back within the passageway in the upstream direction.
- A combination as claimed in claim 1, the spring member deflectable from the unbiased position to a first of the biased positions when the pressure differential is equal to a first pressure level,
the piston head member having a peripheral circumferential edge portion for engagement with the tube inner wall to prevent fluid flow axially therebetween unless the pressure differential is exceeds the first pressure level,
the peripheral circumferential edge portion of the piston head member being elastically deformable between an unbiased condition and biased conditions wherein in the unbiased condition the edge portion engages the tube inner wall to prevent fluid flow therepast and in the biased conditions the edge portion elastically deflects away the tube inner wall to permit fluid flow in the downward direction therepast,
the edge portion of the piston head member assuming the unbiased condition when the pressure differential is less than or equal to the first pressure level,
the edge portion of the piston head member assuming the biased conditions when the pressure differential exceeds the first pressure level. - A combination as claimed in claim 10 wherein the spring member assumes the unbiased position when the pressure differential is approximately zero.
- A combination as claimed in claim 10 or 11 wherein:the spring first end is fixed to the inner wall of the tube member at the first location which is axially upstream from the spring second end,the spring member in moving from the unbiased position to the biased positions is extended to axially increase in length between the spring first end and the spring second end.
- A combination as claimed in claim 10 or 11 wherein:the spring first end is fixed to the inner wall of the tube member at the first location which is axially down stream from the spring second end,the spring member in moving from the unbiased position to the biased positions is compressed to axially decrease in length between the spring first end and the spring second end.
- A combination as claimed in any one of claims 1 to 13 wherein the valve member including the spring member and the piston head is integrally formed as a unitary element by injection moulding.
- A combination as claimed in any one of claims 1 to 14 wherein in operation to discharge a fluid through the tube member past the valve member:a. starting with an initial pressure differential less than the first pressure level and increasing the pressure differential to the first pressure level, the spring second end is moved axially in a downstream direction with the edge portion of the piston head member in the unbiased position prevent fluid flow therepast,b. on further increasing the pressure differential from the first pressure level to pressure differentials which exceed the first pressure level the edge portion of the piston head member assumes the biased conditions in which the edge portion elastically deflects away the tube inner wall to permit fluid flow therepast,c. on decreasing the pressure differential from pressure differentials which exceed the first pressure level to the first pressure level the edge portion of the piston head member assumes the biased condition in which the edge portion prevents fluid flow therepast and the spring second end moves to the first of the biased positions,d. on further decreasing the pressure differential from the first pressure level to pressure differentials which are less than the first pressure level with the edge portion of the piston head member in the biased conditions in which the edge portion prevents fluid flow therepast, the spring member deflects under its inherent bias moving the spring second end in an upstream direction from the first of the biased positions towards the unbiased position, wherein in the moving the spring second end in the upstream direction from the first of the biased positions towards the unbiased position with the edge portion of the piston head member engaging the tube inner wall to prevent fluid flow therepast and fluid on the downstream side of the piston head member is drawn within the passageway in the upstream direction,
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2780503A CA2780503C (en) | 2012-06-19 | 2012-06-19 | Telescopic bell piston for pump |
CA2808550A CA2808550C (en) | 2012-06-19 | 2013-03-08 | Drawback check valve |
Publications (2)
Publication Number | Publication Date |
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EP2676737A1 true EP2676737A1 (en) | 2013-12-25 |
EP2676737B1 EP2676737B1 (en) | 2019-02-27 |
Family
ID=48613530
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP13172419.7A Active EP2676737B1 (en) | 2012-06-19 | 2013-06-18 | Drawback check valve |
Country Status (2)
Country | Link |
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EP (1) | EP2676737B1 (en) |
CA (1) | CA2808550C (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015048698A1 (en) * | 2013-09-30 | 2015-04-02 | Gojo Industries, Inc | Dispensers, refill units and pumps having suck-back features |
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US8070844B2 (en) | 2007-08-31 | 2011-12-06 | Maguire Stephen B | Dust clearing blow-back valve and reservoir |
EP2446971A1 (en) * | 2010-11-01 | 2012-05-02 | Gotohti.com Inc. | Telescopic piston for pump |
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JPS62129168A (en) * | 1985-12-02 | 1987-06-11 | Tokushu Aerosol Kk | Apparatus for distributing creamy fluid |
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WO2015048698A1 (en) * | 2013-09-30 | 2015-04-02 | Gojo Industries, Inc | Dispensers, refill units and pumps having suck-back features |
Also Published As
Publication number | Publication date |
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CA2808550A1 (en) | 2013-12-19 |
CA2808550C (en) | 2021-07-20 |
EP2676737B1 (en) | 2019-02-27 |
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