US2907279A - Variable capacity pump - Google Patents

Description

r 9 JJ .fz 664,@ Jr l www l/)`- j l Oct. 6, 1959 E, J, CARLETQN .2,907,279

VARIABLE CAPACITY PUMP Filed Jan. 24, 1955 2 SheetsSheet 1 Oct. 6, 1959 E. J. cARLE'roN 2,907,2- 79 VARIABLE CAPACITY PUMP Filed Jan. 24, 1955 2 Sheets-Sheet 2 INVENTOR EMME J.' CARLrToN BY @JM VARIABLE' CAPACITY PUMP Application January 24, 1955, Serial No. 483,744 11 Claims. (Cl. 103-120) This invention relates to an improvement in rotary variable capacity pumps, and more particularly to means by which the volume and pressure of the fluid delivered by the pump may be regulated without changing the speed at which the impeller is driven.

One object of .the invention is to provide `a pump of the above character in which the pump capacity or delivery may be automatically varied from maximum vto substantially zero in response to thepressure in the working line.

A further and more particular object is to provide a pump of the above character in which the capacity control of the pump may hunt over normal variations in Working pressures but in which, from an idling operation of the pump, substantially full operating pressure may be instantly delivered to the working line without delay forthepump pressure to build up.

A vfurther object is the provision of improved means for varying the eccentricity of the peripheral wall of the pump chamber in which an impeller having sliding vanes operates.

In a preferred form of the invention both the general and particular objectives are in part obtained by discharging the Vpump output directly through the chamber ofa pressure accumulating cylinder.

Other and further objects will'be made apparent in the disclosure ofthe accompanying drawings and in the following speciiication and claims.

:In the drawings,

Fig. 1 is a side elevational view, parts cnt away, showing a pump embodying the invention;

Fig. 2 is a section substantially on line 2 2 of Fig. l;

Fig. 3 is a view similar to Fig. 2 except the pump is in a neutral or idling condition;

Fig. 4 .is.a view similar to Fig. l; but in a neutral or idling c.Onditiong Fig. A5 is a fragmentary section substantially on line 5-,-5 ofFig. 2;

Fig. 6 is a vfragmentary sectional elevational View of substantially what is shown 'in Fig. 5 rotated 90;

.Fig. 7 =is a-side. elevational View of a modified application of the invention, ,in pressure generating condition; and

Fig. 8 Aisa `detail view similar'toFig. 4 showing an alternative cam arrangement.

Referring to the drawings the vpump proper comprises ('FigsfSV and 6) opposed casing members 1 and 2, the former formed 'with a central opening and the latter formed with a cylindrical recess generally designated at 3 'inwhich the pump impeller 4 is yrotatably mounted. Theimpeller 4 'is keyed as at 5 (Fig. 6) to a shaft 6 which is journaled Vin bearings 7 and 8 formedrespectively in members 1 and `2. Shaft 6 extends outwardly of bearing 7 and is .keyed gas at 9 to a driving pulley or o ther power source, not shown. The opening in the inner'face of casing member 2, adjacent the inner end of shaftf yis covered by a circular disc 10. Snap rings 11 hold the impeller centered on shaft 6 and a snap ring 12 holds a suitable packing-13 in place.

United States Patent C) Pce An eccentric annulus /14 (Fig. 2) with circular inner and outer circumferences eccentric to each other vis rotatably fitted within recess 3 of casing member 2, saideccentric annulus has a pin 15 therein, extending radiallytherefrom. Casing member 2 is -relieved along 'its edgeadjacent to eccentric annulus y14 at 16 (Fig. 2) and apassageway 17 extends inwardly fromfsaid relieved portion -16 of eccentric annulus 14, the purposes for which will beeX- plained hereinafter. Apair of arcuate slots v18 and v19 (Figs. 2 and 5) forming passageways in the pump ,chamber side of casingmember 2, are formed adjacent to the hub of impeller 4. Another pair of arcuate slots .20and 21 forming passageways are formed v'in the pump chamber side of casing member 2 in concentric relationto slots 18 and 19, respectively, and adjacent to the outer ends of vanes22 slidably mounted in impeller 4.

A passageway 23 (Fig. 5) extends from arcuate `slot 20 to an annular recess 24 :on the opposite faceof casing member 2. One or more passageways 25 (Fig. '5 1) extend from slot Y18 toA join passageway r23 so as to providecommunication `from slot 18 -to slot 26.

A recess in casing member 2 (Fig. 2) generally indicated by 26 between slots 19 and 21,' forms a passagewaybetween said slots (Figs. 2 and 3).

Passageways .25 kand 26 equalize the pressure of the fluidsurrounding the inner and outer ends of the -vaues of the impeller, thus avoiding binding of the -sidesofthe respective vanes as they vslide back and forth-whilethe impeller rotates within the eccentric annulus.

As shown (Fig. 5), ,casing member 2 has acircular recess 27 outwardly .from annular recess 24 which extends radially Abeyond said annular recess so as to :form a shoulder generally indicated at 28.

An open-end cylindrical piston member 29 having a central recess generally designatedby Sti-inthe outer-face of its closed endand a shoulder 31 aroundthe periphery of its open end is slidably positioned in axial alignment with annular recess 24 so that the annular ange 32 formed aroundthecentral recess 30 enters said annular recess 24 in casingmember 2. v

Piston 29 operates in a cylinder 33. extending from and secured in any suitable vmanner to the casing member 2 at 34 with its ,adjacent end tted lagainst shoulder 28.l The free end of .cylinder 3 3 acts as a stop forgpiston member 29 when said piston is moving towards'the-pump, by engaging with shoulder .28 of said piston member.

Said pin 15 extends radially outwards from -the yeccentric annulus 14 (Figs. 2 and 3) Ithrough an elongated slot 35 (Figs. 1 and 4) and is vengaged by a slotted lever member 36 which is pivoted on a pin 37 fixed in a lug 3S extending from casing member 2, .casing member 2 being slabbed on as at 39 to accommodate the lever.Y Said lever member 36 has acam track 40 which has portions forming an angle as indicated by -41, 42 and 43, which is in engagement with cam roll 44 attached to arplate member 45 ixed at 46 to piston 29 and slidafbly mounted in a guideway 47 formed in the outer face of cylinder 33.

Within annular recess 24 (Figs. Y5 and 6), yieldably holds a valve member 49 against the opening or openings from the passageway 23 in casing-member 2 to the expandable chamber 50 between Apiston member 29 and .casing member 2', so as to form a'onefwayvalve 51. Therefore, iiuid kunder pressure :from pump chamber 3 can enter chamber 50, by valve 51, but no fluid can pass from chamber 5t) to pump chamber 3; and the iluid entering through valve 51 passes through and is discharged from chamber 50 52 (Fig. 6), which opens to the discharge opening 53 of the pump.

To prevent the eccentric against the casing member 2 annulus 14 from bearing (as a result of the high a spring 4 8 by way of passageway pressure created in the pump chamber), the uid in the' by having the vdischarge side of said pump chamber in communication with said relieved portion 16 of the casing member 2 by means of passageway 17.

A casing Vmember 54 (Fig. 1) shown in axial `alignment with piston member 29 is secured in spaced relation to casing member Y1 by means of tie rods 55, having threaded ends which screw into casing member 1 and receive nuts 56 on the opposite end, adjacent the outer face of casing member 54. Nuts 57 threaded on the tie rods 55 hold members 1 and 2 in fluid-tight relation. A cylindrically shaped spring guide member 58 in axial alignment with cylinder 33 is adjustably mounted adjacent the inner face of casing member 54 on a threaded stud 59 which is secured to casing member 54 by a nut 60 received by said stud adjacent the outer face of casing member 54. A compression spring 61 is telescoped outwardly of said guide member 58, one end of said spring abutting a disc 62 fixed to the outer end of said guide member 58, and the other end abutting the inner face 63 of piston member 29 (Fig. 5). A second and larger compression spring 64 is disposed in outer concentric spaced relation to spring 61 with one end abutting disc 62 and its other end abutting the open end of piston member 29. A cylindrical shell member 65 is disposed in opposed annular recesses 66 and 67 in the respective inner faces of casing members 1 and 54 and held in place by tie rods 55. An intake opening is generally designated by 68 and a vent 69 are formed in shell member 65.

Expandable chamber 50, which is defined by casing member 2, cylinder 33, and piston member 29 acts as a pressure accumulator chamber, wherein fluid under pressure may be stored. A reservoir for iluid is substantially defined by shell member 65 and the inner faces of casing members 1 and 54, within which the accumulator chamber mentioned above is enclosed.

In the form just described it will be seen that the discharge of the pump passes directly from the pump chamber, through check valve 51 to the chamber of the accumulator cylinder 50, which is formed unitarily with the casing member 2, the accumulator opening to the working line through passage 52, and that the periphera-l surface of the pump chamber is formed by the inner surface of the eccentric annulus 14, the outer surface of which is rotatably fitted in the recess 3 so that the eccentricity of the impeller shaft relative to the pump chamber can be increased, or decreased to the point where the impeller idles in concentric relation to its chamber, by rotation of the annulusr 14, the pressure on the -inn'er ends of the sliding vanes 22 being substantially equalized with the chamber pressures in all posif tions of the impeller by the passages 25 and 26. It will further be seen that the formation of cam track 40 on lever 36, by which rotation is imparted to the annulus 14 to vary the pump capacity is so formed that when the pump is delivering maximum volumeand pressure to the line (and the accumulator) the cam roll-44 may hunt along the straight line portion 41 of the cam permitting acceptable variations in the working pressure in the line but that when resistance in the line increases sufficiently to force the accumulator piston outwardly of its cylinder to the point where cam roll 44 engages the sharply curved portion 42 ofthe cam track, lever 36 swings to rotate annulus 14 toward or to the idling position of the pump, the relatively short inclined portion 43 `and curved portion 4Z of the cam track permitting only slight hunting movement between the full and zerodelivery positions of annulus 14.V Thus when delivery is completelyshut off as by the closure of aY valyein the working line, the-annulus 14 is moved vquickly to idle position when maximum pressure isbuilt up in the accumulator by means of open-end piston member 29 being forced rearwards, compressing springs 61 and 64, and moving cam roller 44 away from the pump along cam track 40 in lever member 36 until pin 15 is pivoted upwardly (Fig. 3), and that when the valve is opened or the demand for fluid pressure otherwise restored, full accumulator pressure-equal to working pressure-is instantly supplied to the line as the annulus is restored to full delivery position giving time for the pump to build up to working pressure. v

While in the preferred form as illustrated in Figs. l to 6 the pump discharges directly through the accumulator formed on one side of the pump casing, the pin 15 being directly actuated from the accumulator, the pin actuation of the annulus renders the pump subject to a wide range of control arrangements. For example in some installations it is desirable to idle the pump in the event that pressure in the discharge line rises to a predetermined point. Such an arrangement is shown in Fig. 7 where the pump casing is formed bytwo members v1'v and 2 chambered as previously described and similarly similarly provided with an impeller operating within an eccentric annulus having a pin 15 extending radially outwardly ofthe casing member through a slot 35 and adapted, as above described, to be rotated to vary the capacity or discharge of the pump. The pin 15 is engaged by the slotted end of a lever 36' pivoted to the pump casing at 70, the opposite end of the lever 36 pivoted to the pump casing 'at 70, the opposite end of the lever being formed with an opening 72. The rod 73 of a piston 74 extends freely through opening 75 and is provided with an enlarged head 76 thus forming a lost-motion connection between the lever and piston rod. Piston 74 operates in a cylinder 77, the upper end of which is connected by pipe 78 to the outlet or pressure side of the pump, the lower end of the cylinder being connected by a pipe 79 to the inlet or low side of the pump. The piston 74 operates between the cylinder openings to the pipes 78 -and y79. The side of piston 74 opening to the pipe 79 is loaded by a compression spring 81 positioned between the piston and a perforated disc or spider 82 xed to the inner end of a screw 83 threaded -through the lower end of the cylinder and providing adjustment of the spring load. As shown the piston 74 in its upper position engages a shoulder 84 thus reducing the area of the piston exposed to the line pressure. In the position of the parts shown in Fig. 7 the pin 15 is in the position corresponding to Fig. 2 with the annulus in position to provide maximum discharge pressure. Referring again to Fig. 7 the spring 81 may be adjusted to yield to any desired degree of pressure in the pressure line 78. When the critical pressure is reached the piston `'7'4- moves downwardly in the cylinder 77 leaving the shoulder 84 and exposing the full surface of the piston to the pressure side of the pump, thus rapidly swinging pin 15' and the annulus to which it is attached to pump idling position. As the pump pressure drops spring 81 restores piston 74 to its uppermost position piston rod 73 moves idly up through opening 75 leaving lever 36', pin 15' and the annulus in pump -idling position until lever 36' is manually, or otherwise, restored to its original position.

As will be apparent if the end of lever 36' is shackled to the free end of piston rod 73, spring 81 may be made to restore the annulus to the full pressure position of Fig. 7 and by suitably adjusting the pressure of spring 81 the piston and cylinder can be made to act as a governor to maintain the pump output constant or variable within prescribed limits either with or without a pressure accumulator in the pump discharge line.

An alternative cam arrangement for actuating the annulus 14 is shown in Fig. 8, in which the plate 45 is replaced by a plate 85 in which a cam slot 86 corresponding in function tocam groove 40 and having substantially the same form in Vmirror image. Plate 85 is provided .with inwardly extending -iianges 87 which guide plate 85 in guideway 47. One end of plate 85 is `fixed to the flange 32 of piston 29 by screws 46' in the same manner as plate 45, the free end of plate 85 extending over, and in spaced relation with, the slabbed oif surface Y39 of casing 2. Cam slot 86 includes a straight portion 41', a curved portion 42 and an inclined portion 43 co-rresponding respectively to portions 41, 42 and 43 of cam groove 4G previously described.

The straight pin 15 in the arrangement previously described is replaced in the Iarrangement of Fig. 8 by a bent pin 15' one end portion of which is fixed in the eccentric annulus and extends outwardly of the casing member 2 through the previously described slot 35. Outwardly of slot 35 pin 15 is bent longitudinallyof and in the direction of the cylinder 34 beneath plate S5, the free end portion of pin 15 being bent radially outwardly for engagement in the cam slot 86. In the position of the parts-shown in Fig. 8, which corresponds to Fig. 1, the free end of pin 15 is positioned 4at the closed end of portion 41 of the cam slot and asrthe accumulator fills and flange 32 moves to -the position of Fig. 4 plate 85 moves within pin 15' and the eccentric annulus to which it is fixed remaining in the position of Fig. 2 until portions '42 and 43 engage the free end of pin 15 to swing pin 15 and the annulus to the idling position of Figs. 3 and 4.

As will be understood cam slot 86 may, if desired, takethe form of a groove cut in theunderside of plate 85.

What is claimed is: y

1. A variable capacity pump comprising a pump casing, a cylindrical chamber formed in the casing, an annular member having cylindrical inner and outer surfaces rotatably mounted in said chamber on the outer surface of said annular member, the said inner surface of said annular member being eccentric with vrespect to the said outer surface thereof, said inner surface forming the peripheral wall of a pump chamber, Va rotary impeller, having slidable vanes, rotatably mounted in said pump chamber, spring loaded means constantly opposed by the pressure in the `discharge line of the pump, and a lost motion connection between said means and said annular' member to rotate the latter to move its inner surface to and from `and lbetween a position of concentricity and a position of a Vpredetermined degree of eccentricity with respect to the impeller as the pressure in the pump discharge line opposing the said spring pressure varies between predetermined Alimits above that provided by said predetermined degree of eccentiicity, said lost motion connection permitting movement of said spring loaded means without movement of said annular member when the discharge pressures opposed to said means are below said upper limit of predetermined pressure, said connection effecting movement of said annular member to vary the capacity of the pump only at discharge pressures above that provided by said predetermined degree of eccentricity of the inner surface of said annular member and with respect to the impeller.

2. A variable capacity pump comprising a pump casing, a cylindrical chamber formed in the casing, an annular member having cylindrical inner and outer surfaces rotatably mounted in said chamber on the outer surface of said annular member, the said inner surface of said annular member being eccentric with respect to the said outer surface thereof, said inner surface forming the peripheral Wall of a pump chamber, a rotary impeller, having slidable vanes, rotatably mounted in said pump chamber, a cylinder, a spring loaded piston operating in said cylinder, a passage connecting the discharge side of the pump to the cylinder to oppose the spring load, a check valve in said passage preventing reverse flow between the pump and cylinder, a pin extending radially outwardly of the pump casing from said annular member, a cam follower carried by and movable with said piston, a lever pivoted to the casing,

one endfof said lever being connected to Isaid pin and the other endof said lever being provided -with -a cam track in which said camlfollowerengages to swing the lever about its pivot to rotate the annular member Vand move'its inner surface to and from and'fbetween a position of concentricity and a position ofeccentricity withrespect to the limpeller as the lpressure at thedischarge side Vof the pump and in-said cylinder varies between predetermined limits.

3. A variable capacity pumpcomprising apump casing, a cylindrical chamber formed in the casing, an .annular member having cylindrical inner and outer surfaces rotatably mounted Vin said chamber ron `the outer `surface of said annular member, the said inner -surface.-of=said annularmember being Aeccentric with respect -to the-said outer surface thereof, said inner surface forming ithe peripheral wall of a pump chamber, 'a rotary impeller, having slidable vanes,'rotatably\mounted in said pump chamber, a pressure accumulator in the form" of -a-n expansible chamber formed on voneV side -of Vthe pump casing, the latter iforming'a fixed -walloftheexpansible chamber, said wall being provided with `an opening through which the pressure side 'of the pump 4chamber discharges directly into said expansible chamber, a -discharge passage from said expansible chamber to the discharge opening of the pump, `the entire discharge Vof the pump passing through said chamber to Vsaid discharge opening ofthe pump, a compression spring loading )the movable wall of the expansible chamber in opposition to the pump pressure therein, the spring loaded side of said expansible chamber being open to the inlet side of the pump chamber, a `pin extending radially outwardly of the pump casing from said annulus, a lever pivoted to the driving engagement-with said pin, and cam means connecting the movable'wall of the vexpansible lchamber tothe other end of said lever to swing the Ilever about -its pivot to rotate rthe annulus and move its-inner surface to and from and Ybetween a position of concentricity and a position of a predetermined degree'of eccentricity vwith respect to the impeller as the pressure in the pump discharge line opposing the spring pressurevaries between predetermined limits.

4. In combination a variablecapacity pump,apressure accumulator, the pump discharginglentirely through the accumulator, la check valve lpreventing reverse flow 'between the pump and accumulator, a spring loaded'member movable in response to any increase of pressure in the accumulator, and means responsive only to that portion of movement of said member effected by pressure inthe accumulator above a predetermined amount, to vary the output of the pump.

5. A variable capacity pump comprising a pump casing, a cylindrical chamber formed in the casing, an annular member having cylindrical inner and outer surfaces rotatably mounted in said chamber on the outer surface of said annular member, the said inner surface of said annular member being eccentric with respect to the said outer surface thereof, said inner surface forming the peripheral wall of a pump chamber, a rotary impeller, having slidable vanes, rotatably mounted in said pump chamber, a pin extending radially from the annulus and through a slot formed in the pump casing, said pin providing means outwardly of the casing to rotate the annulus to move its inner surface to and from and between a position of concentricity and a position of a predetermined degree of eccentricity with respect to the impeller to vary the output of the pump, the casing wall at the pressure side of the annular member being relieved to form a fluid receiving chamber and a passage from said chamber communicating with the pressure side of the pump to equalize the pressure on the inner and outer walls of the annulus member at the pressure side thereof.

6. A variable capacity pump comprising a pump casing, a cylindrical chamber formed in the casing, an

casing, one end of said V-lever making -a annular member having cylindrical inner and outer surfaces -rotatably mounted in said chamber on the outer surface of said annular member, the said inner surface of said annular member being eccentric with respect to the said outer surface thereof, said inner surface forming the peripheral wall of a pump chamber, a-rotary impeller, having slidablevanes, rotatably mountedl in said pump chamber, an intake passage formed in'the casing and opening to the low side of the pump chamber, an expansible chamber including a spring loaded movable wall, a passage formed in the casing through which the high side of the pump chamber discharges to said expansible chamber, a check valve in said last-named passage, a dischargeopeningfrom said expansible chamber to the working line of the pump, the entire discharge of the pump passing through said expansible chamber to the working' line of the pump, and means responsive to the movement of said movable wall within a predetermined range of -pressure in said chamber, which range lies above a predetermined maximum working pressure to rotate said eccentric annulus to and from and between a position of concentricity and a position of a predetermined degree of eccentricity with respect to the impeller.

7. AV variable capacity pump as in claim 6, said lastnamed means comprising a cam and follower between said eccentric annulus and said movable wall.

8. A variable capacity pump comprising a pump casing, a cylindrical chamber formed in the casing, an annular member having cylindrical inner and outer surfaces rotatably mounted ,in said chamber on the outer surface of said annular member, the said inner surface of lsaid annular member being eccentric with respect to the said outer surface thereof, said inner surface forming the peripheral wall of a pump chamber, a rotary impeller, having slidable vanes, rotatably mounted in said pump chamber, an intake passage formed in the casing and opening to the low side of the pump chamber, an expansible chamber including av spring loaded movable wall, a passage formed inthe casing through which the high side of the pump chamber discharges to said expansible chamber, a check valve in said last-named passage, a discharge opening from said expansible chamber, the entire discharge of the pump passing through said chamber and said discharge opening therefrom, a pin extending radially outwardly of the pump casing from said eccentric annulus and means connecting the outer end of said pin and said movable wall to rotate the eccentric annulus and move its inner surface to and from and between a position of concentricity and a position of a predetermined degree of eccentricity with respect to the impeller in response to the movement of said movable wall as the pressure in the discharge line and said expansible chamber varies between predetermined limits.

9. A variable capacity pump as in claim 8, the means connecting said pin and movable wall comprising a cam carried by the movable -wall and engaged by the pin as a follower.

10. A Variable capacity pump as in claim 9, said expansible chamber having at least suicient capacity to maintain working pressure in the discharge line as the eccentric annulus is moved from a position of concentricity to a position of maximum eccentricity.

1l. A variable capacity pump comprising a pump casing, a cylindrical chamber formed in the casing, an annular member having cylindrical inner and outer surfaces rotatably mounted in said chamber on the outer surface of said annular member, the said inner surface of said annular member being eccentric with respect to the said outer surface thereof, said inner surface forming the peripheral wall of a pump chamber, a rotary impeller, having slidable vanes, rotatably mounted in said pump chamber, a pin extending radially outwardly of the pump casing from the annulus, an expansible chamber having a movable wall open at opposite sides to the low and high sides of the pump, a check valve in the opening from the high side of the pump to said chamber, an opening from said chamber to the pump discharge line, the entire pump discharge passing through said chamber and said last-mentioned opening, a compression spring loading that side of the movable wall which is open to the low side of the pump and means connecting the movable wall of the expansible chamber to said pin to rotate the annulus and move its inner surface to and from and between a position of concentricity and a position of a predetermined degree of eccentricity with respect to the impeller upon movement of said movable wall as the pressure in the pump discharge line opposing the spring pressure varies between predetermined limits.

References Cited in the tile of this patent UNITED STATES PATENTS 953,539 Mendizabal Mar. 29, 1910 2,142,275 Lane Jan. 3, 1939 2,166,423 Clark July 18, 1939 2,606,503 Shaw Aug. l2, 1952 2,685,842 Hulerd Aug. l0, 1954 FOREIGN PATENTS 234,680 Great Britain May 27, 1925

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