US20070134112A1

US20070134112A1 - Button diaphragm piston pump

Info

Publication number: US20070134112A1
Application number: US11/302,867
Authority: US
Inventors: Evan Hupp
Original assignee: Individual
Current assignee: Evergreen Packaging LLC
Priority date: 2005-12-14
Filing date: 2005-12-14
Publication date: 2007-06-14
Also published as: WO2007070317B1; WO2007070317A1; TW200732557A

Abstract

A system, method, and process of using a button diaphragm for a piston pump are provided. The button diaphragm is a thin sheet of material with a raised bead located on its periphery. The button diaphragm also has a button with a button face and a relief. The button is centered and inserted into a mating receptacle on a piston pump thereby aligning the diaphragm on the piston. When suction is applied to the internal surface of the piston the button diaphragm, is aligned with the piston by the button, and the diaphragm is drawn toward the face of the piston, thereby ensuring the diaphragm is properly seated on the piston during operation of the piston pump.

Description

TECHNICAL FIELD

The present invention relates to a device and method of pumping fluids and more particularly to an apparatus and method for seating sealing diaphragms on piston pumps.

BACKGROUND

Many types of equipment and more specifically product packaging equipment require pumps to move fluid within the system. For many systems, and particularly for systems with requirements for tightness, washability, and hygiene, such as food packaging equipment, it is necessary to isolate the moving parts of the pump from the fluid. Therefore, a particular type of positive displacement pump called a diaphragm or piston pump is commonly used. The diaphragm is often a rolling membrane that is stretched across the piston walls and adapted to be in contact with the piston in order to maintain a tight barrier to prevent leakage of the pumped fluid. During operation, the piston drives the diaphragm to alternatively increase and decrease the volume of a pump chamber to suction fluid into and expel fluid from the chamber. The accuracy, performance, reliability, and longevity of the diaphragm are related to the ability to correctly seat the diaphragm to the piston.
Therefore, there is a need for a method, apparatus, and process for pumping fluids using a piston pump with a diaphragm and more particularly to an apparatus and method for seating the sealing diaphragm on a piston pump.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures depict multiple embodiments of a diaphragm and use of the multiple diaphragm embodiments in a piston pump and in a piston pump that is part of a larger product fill system. A brief description of each figure is provided below. Elements with the same reference numbers in each figure indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawings in which the reference number first appears.
FIG. 1 a is a perspective view of one embodiment of a button diaphragm.
FIG. 1 b is a cross-sectional view of one embodiment of a button diaphragm.
FIG. 1 c is a close-up cross-sectional view of one embodiment of a button diaphragm.
FIGS. 2 a and 2 b shows a cross-sectional view of one embodiment of a button diaphragm interfacing with one embodiment of a piston head.
FIGS. 3 a and 3 b shows a close-up cross-sectional view of one embodiment of a button diaphragm engaging one embodiment of a receptacle on a piston head.
FIG. 4 is a cross-sectional view close-up of the piston head assembly with one embodiment of a button diaphragm installed.
FIG. 5 is a cross-sectional view of a product fill system with a piston actuated pump with one embodiment of a button diaphragm installed.

DETAILED DESCRIPTION

FIG. 1 a shows a perspective view of one embodiment of a button diaphragm 100. A cross sectional view of the button diaphragm 100 is shown in FIG. 1 b. A button 102 is shown in this embodiment in the center of the contact face 104. The opposite surface of the contact 104 is the fluid face 110. The button diaphragm 100 has a radially disposed flange 106 with a raised bead 108. Between the radially disposed flange 106 and the diaphragm face 104 there is a convolution region 118 that enables the contact face 104 to be extended and retracted relative to the raised bead 108.
FIG. 1 c is a cross-sectional, close up view of one embodiment of a button 102. The button 102 in this embodiment is substantially cylindrical in shape with a chamfer 112 near the button face 116. The chamfer 112 assists in centering and guiding the button 102 into a mating receptacle 202. A relief 114 is incorporated into the walls of the button 102. The relief 114 is designed to engage the mating receptacle 202 to substantially fix the button 102 in place by securing the edges of the mating receptacle 202 inside the relief 114. The cross-sectional profile of the relief 114 in the embodiment depicted is substantially semi-circular in shape. Alternative cross-sectional profiles of the relief 114 include square, rectangular, ellipsoid, and tapered. Although the button 102 shown in this embodiment is substantially cylindrical in shape, it is apparent to one of ordinary skill in the art that the button 102 could adopt a number of shapes, including rectangular, cubic, parallelepiped, conic, mushroom shaped, and others without substantially varying the functionality of the button 102.
The button 102 is fabricated as one continuous piece with the rest of the diaphragm 100. Alternatively, the button 102 can be assembled with the diaphragm 100 using techniques known to one of ordinary skill in the art including welding, gluing, epoxy, or others. In other embodiments of the button 102, the button face 116 and the chamfer 112 form a continuous button face 116 with the button face 116 adopting a substantially conic, spheric, parabolic, ellipsoid, or other cusp-like shape.
The button diaphragm 100 shown in the embodiment depicted in FIG. 1 is comprised of a single material. The single material is molded to form the components such as the raised bead 108, the radially disposed flange 106, and the button 102 including the button 102 elements such as the button face 116 and the relief 114. The button diaphragm 100 may alternatively be fabricated as separate element and bound, welded, or adhered together. For example, the button 102 maybe fabricated separately, then welded, bonded, or glued to the contact face 104 to form the button diaphragm. The material in the embodiment depicted is an elastomer, Viton. Alternative materials for the diaphragm material include, but are not limited to, polyetheretherketone (PEEK), Polytetrafluoroethylene (Teflon or PTFE), or other types of elastomers such as Neoprene, natural rubber, or Buna-N (nitrile). Different methods of fabricating the diaphragm and alternative materials can be selected by one of ordinary skill in the art based on the product being pumped, and the design of the other piston head assembly 400 components including but not limited to the amount of suction used to hold the contact face 104 during operation and the length of the stroke of the piston 200 during operation.
FIGS. 2 a and 3 a show one embodiment of a button diaphragm 100 separated from the mating receptacle 202 on the piston 200. The mating receptacle 202 is shown in this embodiment as a through hole in the piston face 204. The piston face 204 has substantially the same surface area as the contact face 104 of the button diaphragm 100. The location of the mating receptacle 202 on the piston face 204 serves to align the contact face 104 when the button 102 is inserted. The mating receptacle 202 also has an internal bead 206 that sized to interface with the relief 114 on the button 102. The size of the button 102 and the chamfer 112 are selected to enable the button to be inserted into the mating receptacle past the internal bead 206.
FIGS. 2 b and 3 b show one embodiment of the button diaphragm 100 engaged with the mating receptacle 202 on the piston 200. The button 102 has been inserted into the mating receptacle 202 thereby fastening the button 102 in the mating receptacle. The interface between the relief 114 and the internal bead 206 substantially fastens the button 102 with the mating receptacle 202, thereby aligning the contact face 104 with the piston face 204 and the button diaphragm 100 with the piston 200.
The button diaphragm 100 shown in FIGS. 2 a and 2 b demonstrates the operation of the convolution 118. The convolution 118 rolls to enable the contact face 104 of the diaphragm to move relative to the raised bead 108 when urged by the piston 200 moving along the translation axis A.
The piston 200 shown in FIG. 2 also has vacuum inlets 210 on piston wall 220. Vacuum inlets 210 allow the fluid to be evacuated from the fluid volume 214 thereby causing the fluid volume 214 to be at a reduced pressure or partial vacuum (hereinafter vacuum) relative to the outside environment. On the piston face 204, there is a vacuum face 212. The vacuum face 212 is less than or equal to the surface area of the piston face 204. The vacuum face 212 enables the reduced pressure of the fluid volume 214 to be applied to the contact face 104 of the button diaphragm 100. The suction force generated by the vacuum in the fluid volume 214 further affixes the button diaphragm 100 to the piston 200 to keep the contact face 104 affixed to the piston face 204 during normal operation of the piston pump. The vacuum face 212 can be comprised of a semi-permeable surface including, but not limited to sintered materials, mesh, or a perforated material with holes or slots or other small passages through the piston face 204.
FIG. 4 is a cross-sectional view of the piston head assembly 400 with an embodiment of the button diaphragm 100 installed. In this particular view, the button diaphragm 100 is shown extended and separated from the piston 200 for clarity. The piston head assembly 400 includes the piston 200 with the button diaphragm 100 which is typically fastened to the piston face 204 using both the button 102 installed in the mating receptacle 202 as well as the suction applied to the contact face 104 by the vacuum face 212. The suction is normally applied to the button diaphragm 100 during startup and normal operation of the product fill system 500. The button 102 when installed in the mating receptacle 202 works to ensure the button diaphragm 100 is properly seated on the surface of the piston face 204. The axis of translation for the piston during operation is highlighted by the arrow A1-A2.
A pump chamber 404 is in fluid communication with a product inlet 406 and a product outlet 408. The piston 200 is shown in FIG. 4 in the retracted position while the button diaphragm 100 is shown in the extended position. The button diaphragm 100 is urged into and out of the pump chamber 404 by the movement of the piston 200 along the axis of translation A1-A2. During operation, the movement of the button diaphragm 100 is urged by the piston 200 in the direction A2, thereby expanding the volume of the pump chamber 404. The expansion of the pump chamber 404 volume creates a partial suction to urge the product to flow into B1 the pump chamber 404. When the button diaphragm 100 is urged by the piston 200 in the direction A1, the volume of the pump chamber 404 is reduced. The reduction of the pump chamber 404 volume forces the product to flow out B2 of the pump chamber 404 thereby pumping the product. During the entire operation the product is isolated from all of the pump components other than the fluid components. The fluid components of the pump include the fluid face 110 of the button diaphragm 100 and the fixed internal surfaces of the product inlet 406, product outlet 408 and the pump chamber 404.
The piston head assembly 400 has an outer cylinder 410. The outer cylinder 410 is connected to the pump head 412. The internal surfaces of the pump head 412 form the fixed internal surfaces of the product inlet 406, product outlet 408, and the pump chamber 404. The pump head 412 also provides the primary means for interfacing with the other elements of the product fluid piping through flanges 414. The pump head 412 is attached to the outer cylinder 410. The attachment means can comprise either a series of bolts, clamps, v-band clamp, or other means known to those of ordinary skill in the art to connect fluid components. In the case of the embodiment depicted in FIG. 4, a v-band clamp 416 is used to attach and seal the pump head 412 to the outer cylinder 410.
A groove 418 is formed between the mating surfaces of the outer cylinder 410 and the pump head 412. The groove 418 is sized to accept the raised bead 108 on the button diaphragm 100. The raised bead 108 is compressed inside the groove 418 to capture the button diaphragm 100 and form a fluid tight seal. The corners of the pump head 412 and the outer cylinder 410 in the region of the interface with the button diaphragm 100 are radiused to accept the radially disposed flange 106. The fluid tight seal separates the pump chamber 404 from the rest of the piston head assembly 400.
The outer cylinder 410 has a backside flange 434 on the opening opposite the side facing the pump chamber 404, referred to as the backside of the outer cylinder 410. The backside flange 434 has a backside groove 432. The backside groove 432 is configured to accept a backside diaphragm bead 422. The backside diaphragm bead 422 is part of the backside diaphragm 420. The backside diaphragm 420 seals the backside of the outer cylinder 410. The opposite edge of the backside diaphragm 420 has a backside diaphragm piston bead 442. The backside diaphragm piston bead 442 is seated inside the backside piston groove 440. The backside piston groove 440 is sized to accept the backside diaphragm piston bead 442 such that when the piston drive connector 450 is mounted to the piston 200 using bolts 452, the compression of the piston drive connector 450 against the piston 200 compresses and expands the backside diaphragm piston bead 442 to create a substantially air tight seal between the piston 200 and the outer cylinder 410. The backside diaphragm has a convolution 428 that enables the diaphragm to roll in the space between the piston wall 220 and the interior walls of the outer cylinder 410 as the piston 200 travels back and forth along the axis A1-A2.
The outer cylinder 410 has a vacuum inlet 460. The vacuum inlet 460 is mounted along the outer cylinder 410 between the backside bead groove 432 and the raised bead 108. The vacuum inlet 460 is attached to a suction source, not shown. The suction source can be an external pump, blower, or even a factory-wide suction system. The suction source evacuates air from an interior area defined by the inside walls of the outer cylinder 410, between the button diaphragm 100 and the backside diaphragm 420. The interior area is sealed to enable air to be evacuated and for the interior area to be held at a reduced pressure (vacuum). Since the interior area encompasses the piston 200 and more specifically the vacuum inlets 210, the fluid volume of the piston 214 is also held at substantially the same reduced pressure. In some embodiments a sensor such as a capacitive humidity sensor, is included in either the vacuum inlet 460, the fluid volume 214, or between the vacuum inlet 460 and the suction source to detect if a rupture of the button diaphragm 100 has occurred allowing product to enter the area of reduced pressure.
When the suction source is applied to the vacuum inlet 460, the fluid or air inside the interior area is removed. As the air is removed a vacuum is developed inside the space including the fluid volume 214 inside the piston 200. The vacuum inside the fluid volume 214 draws air through the vacuum face 212 creating suction across the vacuum face 212 of the piston 200. The suction across the vacuum face 212 is applied to the contact face 104 of the button diaphragm 100. The suction adheres and secures the button diaphragm 100 to the piston 200 to ensure there is no separation while the piston 200 is moving into and out of the pump chamber 404 to pump the product.
The button diaphragm 100 is mounted across the piston face 204. In order for the convolution 118 of the button diaphragm 100 to roll smoothly as the piston 200 travels into the pump chamber 404 in direction A1 and out of the pump chamber 404 in direction A2 the button diaphragm 100 needs to be properly aligned or seated. When the suction is applied to the vacuum face 212 the button diaphragm 100 is pulled toward to piston face 204 and adhered to the piston face 204. During this phase it is possible for the button diaphragm 100 to become misaligned with the piston face 204 resulting in less than optimal convolution 118. To ensure proper seating of the button diaphragm 100 on the piston 200, the button 102 is inserted into and held within the mating receptacle 202 to align the contact face 104 of the button diaphragm 100 with the piston face 204 prior to application of the vacuum. The alignment of the button diaphragm 100 and piston face 204 is maintained initially by the button 102 and the mating receptacle 202. When suction is applied to the vacuum face 212, the diaphragm is drawn toward the piston face 204 and held in place primarily by the suction. Prior to, and during the suction process the button 102 and its interaction with the mating receptacle 202 ensure the proper alignment of the button diaphragm 100 with the piston 200. After the button 102 is inserted into the mating receptacle 202 the first time, the button 102 holds the button diaphragm 100 in proper alignment with the piston 200, even if the vacuum is released. The button diaphragm 100 is thus held concentric relative to the piston 200 even when there is no suction applied to the piston head assembly 400. During normal operations, the button diaphragm 100 is substantially held in place by the suction across the vacuum face 212 of the piston 200.
Alternative embodiments of the button diaphragm 100 include replacement of the single button 102 substantially centered on the contact face 104 depicted in the embodiment shown with a plurality of buttons 102 distributed across the contact face 104. Alternative arrangements of multiple buttons 102 include orienting the centers of the buttons on a spiral ring or concentric rings or near in defined quadrants of the contact face 104. As the button(s) 102 are distributed across different locations on the contact face 104 the mating receptacles 202 are also adjusted on the piston face 204 to ensure alignment of the button diaphragm 100 to the piston 200.
Referring now to FIG. 5 the product fill system 500 and the fill pump assembly 550 is shown. The fill pump assembly 550 is comprised of three major component assemblies. The first component assembly is the drive motor 530. The second is the linear actuator 532. The third element of the fill pump assembly 550 is the piston head assembly 400.
Referring to the product fill system 500, the product to be dispensed 501 is held in a product holding tank 502. The product holding tank 502 is connected via product inlet piping 504 to the fill pump assembly 550 via the pump inlet 406. The product inlet piping 504 may include product metering and measurement apparatus and one-way flow or check valves as known to those of ordinary skill in the art. The product is pumped out of the pump chamber 404 through the product outlet 408 and out of the fill pump assembly 550. A product dispensing mechanism 506 is attached to the product outlet 408. The product dispensing mechanism 506 may include product metering and measurement apparatus and one-way flow or check valves as known to those of ordinary skill in the art. The product dispensing mechanism 506 feeds a product dispensing nozzle 508. The product dispensing nozzle 508 dispenses the product into a container 510 where the dispensed product 512 accumulates.
The fill pump assembly 550 is mounted on a pump support 520. The pump support 520 provides a means for assembling, manipulating, and mounting to external surfaces the multiple elements of the fill pump assembly 550 to the product fill system 500. Mounting bolt(s) 526 for the piston head assembly 400 attach the piston head assembly 400 to the pump support 520. A drive support 522 is also attached to the pump support 520 to hold the linear actuator 532 relative to the piston head assembly 400. A motor support 524 is attached to the linear actuator 532 to hold the drive motor 530. The embodiment depicted shows these three supports, however additional supports maybe added or support removed from the fill pump assembly 550 by one of ordinary skill in the art so long as the overall goal of orientating the elements of the fill pump assembly 550 with the remainder of product fill system 500 are achieved.
The motor 530 provides the primary drive action for the piston 200. The motor 530 is nominally an electric servo motor to control the piston 200 stroke (defined as the distance the piston 200 travels into the pump chamber 404 in direction A1 and out of the pump chamber 404 in direction A2. The motor 530 produces a rotary output on its output shaft 540. The output shaft 540 is linked to a linear actuator 532 via the motor to linear actuator coupler 536. The linear actuator 532 transforms the rotary motion applied via the linear actuator coupler 536 to a linear motion substantially oriented along the axis of travel A1-A2 for the piston 200. The linear actuator output shaft 534 is attached to the piston drive connector 450 via a coupler 538. The coupler 538 can be adjusted to absorb relatively small mismatches in orientation between the linear actuator output shaft 534 and the piston drive connector 450. The coupler 538 also enables the linear actuator to both drive the piston 200 into the pump chamber 404 in direction A1 and pull the piston 200 out of the pump chamber in direction A2.
The motor 530 and linear actuator 532 may be replaced by a number of different alternative drive systems as known to one of ordinary skill in the art. For example, the motor 530 can be a variety of different motor types including, but not limited to DC brushless, DC coreless, AC induction, AC synchronous, stepper, hydraulic or pneumatic motors. The servo feedback mechanism may be integrated with the motor itself, inherent to the motor, or even integrated into the linear actuator. Another alternative embodiment would replace the motor 530 with a linear motor that acts as a powered linear actuator 532. An electronic, hydraulic, or pneumatic linear motor directly converts the energy applied to the motor to linear motion thereby eliminating the need for the motor to linear actuator coupler 536 and reducing the overall component count.
The product fill system 500 is controlled by an electronic control system (not shown). The electronic control system is a digital computer control system. The digital computer control system may operate as a programmable logic controller (PLC) or other real-time controller. The digital computer control system accepts a variety of different inputs from sensors and command inputs and operates the system according to control logic. The different types of sensor inputs can include, but are not limited to, piston 200 position, vacuum or fluid monitoring in the fluid chamber 214 or other components of the vacuum system, motor 530 temperature, motor 530 power output, product flow, carton 510 placement, and other parameters known to those of ordinary skill in the art. The command inputs can include, but are not limited to, commands such as start, stop, and operate. The digital computer control system may record information gathered from sensors and record commands given during operations for diagnostic and other reporting requirements. The recorded information can be either stored locally on the controller or forwarded via a network to an external database (not shown). In alternative embodiments, the control of the product fill system 500 maybe accomplished via discrete electronic components, electromechanical components, hydraulic or pneumatic couplings or other combinations thereof as known to those of ordinary skill in the art.
The embodiments of the invention shown in the drawings and described above are exemplary of numerous embodiments that may be made within the scope of the appended claims. It is contemplated that numerous other configurations of button diaphragm including piston head assembly and product fill systems may be created taking advantage of the disclosed approach. It is the applicant's intention that the scope of the patent issuing herefrom will be limited only by the scope of the appended claims.

Claims

1. A button diaphragm for a piston pump, comprising:

a raised bead located on the periphery of the button diaphragm;

a thin sheet of material connecting the area inside said raised bead; and,

a button located on said thin sheet, wherein said button comprises a button face and relief.

2. A button diaphragm for a piston pump as recited in claim 1, wherein said raised bead, said thin sheet, and said button are fabricated from the same material.

3. A button diaphragm for a piston pump as recited in claim 2, wherein said material is an elastomer.

4. A button diaphragm for a piston pump as recited in claim 1, wherein said button is molded as an integral part of the button diaphragm.

5. A button diaphragm for a piston pump as recited in claim 1, wherein said button is located substantially near the center of the area of said thin sheet or material.

6. A button diaphragm for a piston pump as recited in claim 1, wherein said button relief is substantially semicircular in profile.

7. A button diaphragm for a piston pump as recited in claim 1, wherein said relief is configured to engage a mating receptacle on the piston pump.

8. A button diaphragm for a piston pump as recited in claim 1, wherein said button face is substantially of a shape selected from the group consisting of cylindric, conic, spheric, parabolic, or ellipsoid.

9. A fill pump assembly, comprising:

a pump head with a product inlet and product outlet defining a pump chamber in fluid communication with said product inlet and product outlet;

an outer cylinder attached to said pump chamber with a frontside opening into said pump chamber, and a backside opening, with a groove and backside groove;

a button diaphragm with a raised bead located on the periphery of said button diaphragm attached to said groove. sealing said frontside opening from said pump chamber, the button diaphragm including a button;

a piston sized to fit within said outer cylinder with a piston face, a backside, a drive connector, a mating receptacle sided to accept said button, a fluid volume, and a vacuum face;

a backside diaphragm with a backside diaphragm bead forming a seal with said outer cylinder with said backside groove and a backside piston bead forming a seal with said piston backside; and,

a means for reciprocating said piston into and out of said pump chamber.

10. A fill pump assembly as recited in claim 9, further comprising a suction means for reducing the pressure of said fluid volume.

11. A fill pump assembly as recited in claim 9 whereby said means for reciprocating said piston into and out of said pump chamber is accomplished by a linear actuator.

12. A fill pump assembly as recited in claim 11, further comprising a drive motor with a rotary output coupled to said linear actuator.

13. A fill pump assembly as recited in claim 9, wherein said vacuum face and said mating receptacle are on said piston face.

14. A fill pump assembly as recited in claim 9, wherein the separation between said piston wall and said outer cylinder is sized to accommodate a convolution of said button diaphragm.

15. A fill pump assembly as recited in claim 9, wherein said button further comprises a relief.

16. A fill pump assembly as recited in claim 9, wherein said button diaphragm is an elastomer.

17. A fill pump assembly, comprising:

an outer cylinder attached to said pump chamber with a backside opening and a frontside opening into said pump chamber, with a groove and backside groove;

a diaphragm with a contact face and a raised bead located on the periphery of the diaphragm attached to said groove sealing said frontside opening from said pump chamber;

a piston with a piston face, and a backside, sized to fit within said outer cylinder;

a means of aligning said contact face with said piston face;

a backside diaphragm with a backside diaphragm bead forming a seal with said outer cylinder on said backside groove and a backside piston bead forming a seal with said piston backside;

a means for creating a suction across said piston face and applying said suction to said contact face; and,

a means for reciprocating said piston into and out of said pump chamber.

18. A fill pump assembly as recited in claim 17, where said means for creating a suction across said piston face and applying said suction to said contact face further comprises a sensor means for detecting if product enters said piston.

19. A fill pump assembly as recited in claim 17, whereby said means of aligning said contact face with said piston face is the interface of a button placed on said contact face inserted into a mating receptacle sized to accept said button on said piston face.

20. A fill pump assembly as recited in claim 17, whereby said means for reciprocating said piston is a linear actuator.