US2246951A - Pump unit for liquid dispensing apparatus - Google Patents

Description

June 2'4, 1941 "'PUMP`UNIT4FOR LIQUID YDISPENSING yAPPARATUS W. J. PETER Filed Feb. l5, 1938 5 Sheets-Sheet 1 ATTORNEYS June 24', 1941. l w. J. PETER Y PUMP UNIT AFoa LIQUID UrsyENsING APPARATUS Filed Feb. 15, 1958 l 5 sheets-sheet 2 INVENTOR WILLIAM J. PETER .SYM @ff/71W ATTORNEYS Ju'ne 24, 1941. w. J. PETER PUMP UNIT FOR LIQUID DISPENSING APPARATUS Filed Feb. 15, 193e s sheets-sheet s INVENTOR BY-WILLIAM J. PETER Mlnfw ATTORNEYS June 24, 1941. w. J. PETER PUMP UNIT FOR LIQUID DISPENSING APPARATUS 5 Sheets-Sheet 4 Filed Feb. 15, 193,3

li i! nl I |NvENToR WILLIAM J. PETER ATTORNEYS Jun 24, 1941 Filed Feb. 15, ,1938

5 Sheets-Sheet 5 MWVW ATTORNEYS Patented June 24, 194i PUMP UNIT FOR LIQUID ISPENSING APPARATUS William J. Peter, New YorkN. Y., asslgnor vto l --I vAqua Systems Inc.. a corporation of New York Application February 15, 1938, 'Serial No. 190,559 3 Claims. (Cl. 10S-42) -vide the pump with a by-pass controlled by a pressure operated valve so-that when the pump motor is energized while the nozzle discharge valve is in closed positlomthe by-pass valve will operate to permit the liquid discharged from the pump housing to be returned to the suction side of the pump. A ydisadvantage of the by-pass valve type of dispensing apparatus lies in the fact that the pump is required to force the liquid through the by-pass valve against the pressure exerted by the valve spring thereby increasing the power consumption normally required to maintain operation of the pump.

The use of a centrifugal pump for dispensing apparatus has been suggested for the purpose of eliminating the by-pass valve, the operating characteristics ci the centrifugal pump being such that the power input to the centrifugal pump decreases as the effective head or resistance to flow is increased. Another desirable feature of the centrifugal pump resides in the fact that the power input required to start a primed centrifugal pump -with the discharge valve closed is only 40 to 50 percent of that required for full load, the pump operating merely and suction line must both be completely filled with liquid before the pump will work. If air or gas is permitted to enter the pump or suction line at any time, such as by permitting the supply tank to become drained or by the occurrence of a leak in the suction line, its presence will prevent the pump from developing the necessary vacuum and discharge pressure for successful operation.k Again, if the supply tank or the liquidlevel therein should be at any appreciable distance below the pump, the weight of the liquid in a primed suction line may be sufiicient to cause a vacuum condition which would tend to vaporize highly volatile gasolines and thereby provide a body of 'gas in the pump chamber sufficient to prevent the pump from developing the necessary vacuum and discharge pressure for successful starting operation. thus encountered in the use of a centrifugal pump in dispensing apparatus is readily apparent for/the reason that an operator cannot afford the time required to prime a centrifugal pump, should priming be necessary, before each dispensing operation, or even the trouble of priming the pump after each refilling of the supply tank. A.

A gear pump of the positive displacement type v has heretofore been modified to'include certo churn the, liquid within the pump housing until the discharge valve is opened. A pump, therefore. having these operating characteristics which distinguish a centrifugal pump from the positive displacement type of pump is vdesirable for use in a dispensing apparatus where the pump may be required to operate as-much as 50 per cent or more of the time without liquid actually being dispensed from the system for the reason that operating costs would thereby be reduced and the cost oi' the heretofore necessary by-pass valve interconnecting equipment eliminated,

The application of the centrifugal type of pump for use in dispensing apparatus such as used for dispensing gasoline for automobiles,

presents difficulties of such importance that their use in gasoline dispensing apparatus is in many cases impractical. For example, if the suction of the centrifugal pump is depended upon for lifting liquid to the pump chamber, the pumpmust be maintained in primed condition for successful operation; that is. the pump chamber tain of the desirable operating characteristics of a centrifugal pump. This type of pump is provided with pinion and ring gears, the ring gear being slidably keyed to a drive shaft and biased by a spring for bearing and sealing engagement with portions of' the pump housing. Since the ring gear is loosely supported upon the drive shaft, the bearing surfaces of the housing are mainly relied upon for the maintenance of the rotor assembly in true operating condition. The ring gear being thus loose on the drive shaft, tends to cant and unevenly wear the bearing surfaces ofthe housing, thereby materially reducing the sealing effect.' This causes undesirable slippage of liquid and decreased eiilciency. ,v

One of the severall objects of. my invention, therefore, is to construct an improved pumping unit of the gear type having desirable operating characteristics of both the positive displacement type of pump and the centrifugal type of pump, whereby it will operate to move fluid by positive displacement until opposed by a back pressure of a predeterminedamount, and thereafter, upon further increase of back pressure, will tend to idle. similarly as in the case of a centrifugal PUUIIL J The dimculties Another object of my invention is to construct an improved pump which will operate as a positive displacement pump until subjected to a back pressure or head of a predetermined amount, and thereafter-will provide for a definite return iiow of liquid within the pump housing as the'back pressure is further increased, the power demand being decreased as the return flow is increased.

Another object of my invention is to construct an improved pump having operating characteristics such as will permit continued operation of the pump with occasional deliveries of liquid without the use of the usual pressure operated by-pass valve heretofore required with positive displacement pumps. g

Another object of my invention is to provide a compact pumping and metering unit for liquid dispensing apparatus. Y

Another object of my invention is to provide a compact pumping unit for liquid metering apparatus lwith an' improved means for effectively separating air and gas from the liquid prior to the delivery of the liquid through the meter.

Another object or my invention is to provide a novel combined pumping and air separating unit.

A further object of my invention is to so construct and arrange a pump housing and drive shaft bearing means as to eliminate the usual stuillng box heretofore found necessary for the drive shaft to prevent leakagefrom the pump housing.

A still further object of my invention is to so combine an air and liquid separator with a pump in a single unit so that the usual stuillng box, heretofore provided to prevent leakage about the pump shaft, is eliminated. i

A still further object of my invention is to provide means including bearing structure for a pumping unit which will prevent liquid from leaking therefrom along the drive shaft thereof and at the same time render the pump assembly highly sensitive to forces applied axially thereof. The foregoing objects and others ancillary thereto are accomplished by my invention as follows:

In order to provide a dispensing pump comhining the desirable operating characteristics of both the positive displacement type of pump and a centrifugal type of pump, I have constructed a compact pumping unit comprising a casing enclosing a pump housing, a pressure chamber and an expansion chamber with connecting passages therebetween. The pump housing and expansion chamber are so arranged that the drive shaft extends through the latter wherein an adjustable spring and thrust bearing assembly is mounted on the shaft to eectively urge the pumping elements against an end plate or other appropriate wall portion of the pump housing to insure positive displacement of liquid by the pump until a back pressure of an amount sufficient to force the pumping elements from the end plate against the action of the spring is established. Upon movement of the pumping elements axially of the pump shaft, the seal between the pumping elements and the end plate of the hous-` tablishment of such return passage permits liquid to flow freely across the unsealed end of the pmnping elements, whereupon the pumping elementstend merely to idle at reduced power conshaft extending therethrough. Any liquid leaking from the pump housing through theA drive shaft bearing is collected in the adjacent chamber and returned to the suction side of the pump. the liquid in the chamber being maintained at a level below the drive shaft by means oi' a float controlled valve.

Byeliminating the usual stufling box and providing a liquid return chamber through which the drive shaft extends, bearing structure may be selected for the drive shaft which will permit the pump assembly to be highly sensitive to forces applied axially thereof. i

For a more complete understanding of the invention, reference may be had to the accompanying drawings, in which:

Figure 1 is a view in elevation of a gasoline dispensing pump with the front cover removed disclosing the installation of my novel pumping unit therein:

Figure 2 is a plan view of my pumping unit with the cover portion removed and parts broken away to show, the inlet connection to the pump housing; L

Figure 3 is a view in verticalsection of my novel pumping unit with the parts shown somewhat diagrammatically to illustratethe connective relations thereof;

Figure 4 is the same view as in Figure 3 with the float and valve positions changed;

Figure 5 is a view in vertical section taken approximately along line 5-5 of Figure 3 showing the pumping elements in sealing position for positive displacement of liquid; and

Figure 6 is the same view as in Figure 5 with the pumping elements moved to an unsealed position. j

Referring to the drawings, the pumping unit I0 of my invention is shown in Figure 1 mounted on an appropriate base I2 within the housing i4 of a gasoline dispensing apparatus of the type having aregister I8 for indicating the quantity and cost of the gasoline dispensed. It will be understood, however, that the computing and registering features of the apparatus form no part of the invention, and that the invention is applicable in any of the conventional types of liquid dispensing apparatus used in dispensing gasoline as well as in many other situations.

The casing of the pumping unit i0 comprises a body portion I8 and a cover portion 20 removably secured thereto by bolts 24. A meter 22 is adapted to be secured by stud bolts 25 in communicating relation with flow openings in the upright throat portion 26 'of the cover 20. 'I'he meter shaft 21 is operatively connected to the register I 4 by means of a price variator 28. An electric motor 30 is provided for driving the pump by means of the pulleys 32 and 34 and the belt 36. 'I'he pump moto'rgis controlled by a switch 38 operatively-connected to the hose hook Ill by means of a connecting rod 4I. During a dispensing operation, the gasoline is drawn into the pumping unit from the usual supply tank, not shown, through a suction line 42 and delivered to the meter 22 and thence from the discharge outlet 43 to the nozzle 44 through the v pipe connections 46, the Visaguage 40 and the ho'se 60.

Theldetails of the pumping unit of my invention are best illustrated in Figures v2 to 6, wherein a pump housing 62, a pressure chamber 54, and an air and liquid separating or expansion chamber 66 are shown in a compact arrangement. The pump housing 62 communicates with the suction line 42 by means of an inlet conduit 68 which contains`a'strainerf60. The discharge outlet of the pump housing 62 is connected to the pressure chamber |54 by means of a passage 63 for discharging the liquid tangentlally into the pressure chamber to ald in separating any air or gas held-in suspension in the liquid, the air or gas escaping through the small duct 6d -centrally located in the' top wall 60 of the pressure chamber 56. A liquid outlet pipe 66 has its inlet end located adjacent the lower portion of the pressure chamber 64 and its outlet end communicating with the duct 66 which leads to the meter 22 through the upright throat portion 26. The outlet pipe 56 and duct 08 have been shown diagrammatically in Figures 3 and 4 as being located at one end of the unit for purposes of illustration, they being, in the preferred embodiment, located at the side of the unit opposite the discharge passage 63 as shown in Figures 1 and 2. A check valve "i64 containing a pressure relief valve i2 is located in the outlet of the pipe 66 to prevent drainage of the meter 22 and at the same time relieve any excess pressure that might be developed in the connecting pipes i6 and the delivery hose 66 due to temperature conditions while the pump is standing` idle.

The velocity of the air and gaseous-vapor escaping through' the small duct 6@ and the passage le is reduced upon entering the relatively large expansion chamber 56 so that particles of liquid retained therein are precipitated before l thegas reaches the atmospheric vent tube le located at the opposite side of the expansion chamber. An air valve 80 having a valve stem 62 extending through the duct 64 is pivotally mounted on the short arm 83 of the double lever 8d for controlling the duct 64. A connecting passage 90 between the expansion chamber '56 and the inlet conduit 50 includes a liquid return port 92 which is formed by a valve seat 04 threadably secured in the bottom Wall 96 of the expansion chamber 56. The valve seat 96 is provided with an upright ported sleeve or guide member 97 for slidably engagingthe valve 9B which is connected at 85 to the long arm 86 of the lever 86 by means of a pivoted connecting rod 99. A oat is provided for vertical movement within the expansion chamber and is pivotally connected to the lever 8d at |02.' The double lever 84 is pivotally supported on the upper wall 65 of the pressure chamber at |04. y

The particular positive displacement pump illustrated with my vinvention is of a conventional type, it being understood that other known types of positive displacement pumps may also be modied in accordance with the principles of my invention to produce the desired results obtained by the embodiment illustrated.

The housing 52 of the gear pump used in the illustrated embodiment of my invention is of cylindrical shape and includes a removable wall portion or end plate I0 secured thereto by means of a plurality of bolts |I2. The pumping elements comprise a cylindrical rotor or ring gear ||4 and a coacting pinion or idler gear H6. 75

. shaped element I8.

Across-section which is located between the idler gear and the rotor adjacent one side of the housing, the idler gear being rotatably mounted on a pin ||9 also extending inwardly from the end plate I|0. The rotor I|4 is provided with slots l|20 extending to the end thereof adjacent the end plate IIB. The idler gear ||6 is provided with teeth |2| adapted to engage the slots |20 of the rotor and the inner face of the crescent shaped element |I0. As the rotor ||4 is revolved in a clockwise direction, as viewed in Figures i3 and 4, the idler gear I|6 is engaged in the slots |20 of the rotor on the side opposite the crescent This engagement of the teeth in the slots of the rotor provides an effective seal between the gear H6, the rotor ||4 and the portion of the `pump housing 62 between the inlet and outlet openings to the pump housing. The teeth of the idler gear i I6 begin to withdraw from the rotor slots as they come opposite the housing inlet and are completely withdrawn as they pass beyond the inlet. This withdrawal of the gear teeth from the rotor slots produces a vacuum which draws fluid from the conduit 50 into the voids 'provided by the open slots |20 and the spaces between the teeth |2i, the spaces between the teeth |2| having communication with the conduit 6e by means of the recess |22 in the peripheral portion of the end plate H0. As the gear teeth I 2| and rotor slots |20 `pass beyond the housing inlet, the spaces provided therelby are sealed by the walls of the housing, the

tion with the passage 53. The peripheral portion of the end plate ii has a recess |23 formed therein adjacent the discharge passage 63 through which the fluid contained in the spaces between the teeth |2| may escape as the teeth ire-engage the slots |20. The pumping elements iid and ||6 thus produce a positive displace` ment of fluid from the inlet conduit 58 to the discharge passage 63.

Referring to Figures 5 and 6 of the drawings, the pump housing is shown provided with a bearing IN in a wall |25 thereof contiguousthe expansion chamber 56, the bearing |24 being in alignment with a bearing |26 located in a side wall |21 of the expansion chamber 56. Mounted in the bearings |24 and |26 is a drive shaft |28 connected to the rotor ||4. The bearing |26 isA provided with an inwardly offset portion |30 to accommodate a thrust bearing |32, comprising a stationary portion |34 and a rotatable ring portion |36 between which are located a series of roller. bearings |38. A threaded collar |40 is connected to the drive shaft by means of set` screws |42. Threadably engaging the threaded portion of the collar |40 is an adjustable split collar |44 provided with laterally extended flanges through which a bolt |46 extends for tightening same in the desired position on the threaded portion of the collar |40. A spring element |40 surrounding the shaft |28 is located between they split collar |44 and the rotatable ring element |36 of the thrust bearing |32 for ||5 into sealing relation with the end plate H5.

In order to prevent the building up of pressure in the space |50 on theback side of the rotor ||4,- a small duct |52 is provided in the wall |25 of the pump housing at a point spaced above the bearing |24 so that air and liquid working into the space |50 may be vented into the expansion chamber 55. 'I'he duct |52 is located in the upper part of the housing so as to insure the presence of a body of liquid in the space |50 for the purpose of providing a cushioning enect to supplement the cushioning action of the spring element |48 upon sudden closing .motor switch 85. The starting of the pump motor operates to rotate the pump shaft |25 by means of the belt 35 and the pulleys 52 and 54. The rotor ||4 and the idler gear I |5 in revolving operate as a positive displacement pump and provide a suction in the duct 55, as previously described. Any air or gaseous vapors present in the duct 55 will be withdrawn by the pumping elements ||4 and ||5 and'discharged to the pressure chamber where the air and gaseous vapor will readily escape into the expansion chamber 55 through the open port.54 and eventually to the atmosphere through the vent connection at 15.

If the valve of the 1discharge nozzle remains closed, the further operation of the pumping elements ||4 and H6 in drawing liquid through the duct 55 will build up a back pressure within the pressure chamber which will soon overcome the action of the spring |48 and cause the pumping elements to be forced out of sealing relation with the end plate H0. The breaking of the seal between the pumping elements and the end plate provides a return passage between the discharge and suction sides of the pumping elements through which liquid tends to flow from the discharge to the suction side thereof. The establishment of the return passage by the un- .Q sealing of the pumping elements with respect to the end plate provides a return flow which permits the pumping elements to idle without any further appreciable increase in discharge pressure? As the pressure chamber becomes lled with liquid, a certain amount of the liquid may pass through the small port 64 and enter the expension chamber E5. This overow of liquid together with any liquid that may seep through the bearing |24 and the vent |52 collects in the bottom portion of the expansion chamber. As the level of the liquid in the expansion chamber rises, the float is moved upwardly, thereby tending to close the air valve 50 and open the liquid return valve 95 toward the extreme positions illustrated in Figure 4. The opening of the liquid return valve 55 permits the collected liquid in chamber 56 to flow through the passage 80 into' the suction conduit 55. The relationship between the ` ports 54 and 52 and the float controlled valves therefor are such that the liquid level in the expansion chamber 55 is 2,246,951 the purpose of urging the rotor I4 and idler gear bearings supporting the drive shaft |25. Since the liquid level is prevented. from ever reaching the bearing |25 in the outer wall l.|2l oi the expansion chamber, the usual stulng box hereto- 5 fore found necessary to prevent leakage about the pump shaft is no longer needed in pumping` units constructed in( accordance with my invention.A

The elimination of the usual stuiiing box by Providing a liquid return chamber, such as the expansion chamber 55, adjacent the pump housing with a second bearing -mi in the outer wan thereof, aids'in minimizing the operating fric-` tion on the drive shaft |28 and in maintaining the shaft and pump assembly in a trued relation relative the pump housing. The friction ordinarily exerted bythe presence of the usual studing box thus being eliminated, ,and the level of the liquid inchamber 55 being maintained at a point below the outer bearing |25, the bearings |24 and |25 may be such as to render the pump assembly movable axially thereof upon predetermined small changes in the difference of forces exerted thereon by the spring |45 and 25 the back pressure at the discharge side ofthe pump without the possibility of liquid leaking from the pumping unit at the bearing |25. In this way, the pump assembly is made highly sensitive so as to respond quickly to back pressures ao-exerting axial forces exceeding the predetermined force urging the pump assembly into pumping engagement with the end plate of the pump housing.

When'the. discharge valve of the hose nozzle 44 is opened, the lowering of the back pressure on the discharge side of the pump housing permits the spring |45 to return the pumping elements ||4 and ||5 into sealing relation with the end plate 0, thereby preventing further re- 40 turn ilow of liquid. As long as thedischarge valve is held open by the operator, the pumping elements operate as a positive displacement pump. When the dispensing operation is completed, the closing of the discharge valve causes the back pressure to be again increased by the continued operation of the pump to* an amount suiiicient to overcome the action of the spring |45 and cause the pumping elements to again shift out of sealing relation with the end plate I0. The unsealing of the pumping elements with respect to the end plate of the pump housing Vcauses the pump to operate similarly to a centrifugal pump, the pumping elements tending more and more to merely idle as the back pressure increases above the amount necessary to initiate the unsealing operation until a state of equilibrium between/the back pressure and the unsealed position of the pumping elements has been reached. Since little or no liquid is being actually discharged from the pump housing during the unsealed relation of the pumping elements, the power required to drive the pumping elements is considerably less than that required during the sealed relation thereof, when full capacity discharge of the pumping elements is being performed.

It` will be recognized from the foregoing description of my compact pumping unit that the construction and arrangement of the elements thereof will successfully operate to move or lift liquid by positive displacement until opposed by a back pressure of a selected predetermined amount, and thereafter, to move or lift liquid in decreasing volume as the back pressure is firprevented from ever rising to the height of the ther increased until a state of equilibrium is established, similarly as in the case of a centrifugal pump; that as the back pressure is increased above the predetermined amount the volume of liquid delivered is decreased, and the power required for continued-operation of the pumping elements is also decreased; that air and gas is effectively separated from the liquid prior to the discharge of liquid from the unit or through an associated meter; and that the usual stufllng box heretofore necessary to prevent leakage from the pump housing, at the drive shaft thereof is eliminated.

Although I have shown and described only one specific embodiment of my invention, I am fully aware that many modifications thereof are possible; for example, other types of positive displacement pumps or gear pumps of other designs having the pumping element or elements l thereof resiliently urged in sealing relation with a portion ofthe pump housing may be substituted for the particular pump construction illustrated; and that the end plate or some other part of the pump housing maybe constructed or provided with means responsive to a back pressure in excess of a predetermined amount to break or reduce the sealing relation between the pumping element or elements and the pump housing, whereby the continued operation of the pumping element or elements would tend to merely idle. My invention, therefore, is not to be restricted except in so far as is necessitated by the prior art and the scopeof the appended claims.

I claim:

1. A pumping unit comprising a casing having inlet and outlet connections, a pump chamber in said casing in communication with said connections, a liquid return chamber in communication with said inlet connection, aligned bearings mounted in a wall of said pump chamber and a ywall of said liquid return chamber, a drive shaft supported for sensitive axial movement in said bearings, pumping means secured to said drive shaft and movable therewith axially within said pump chamber, means for resillently urging said pumping means axially into pumping enmeans providing an intercommunicating passage between a space in said pump chamber beto said liquid return chamber of liquid collected ,gagement with a portion of said pump chamber, I

in said space upon axial movement of said pumping means in response to a back pressure in excess of a predetermined amount.

2. A pumping unit comprising a pump housing having inlet and discharge openings, means forming a chamber having a wall in common with said pump housing, a bearing in said common wall and a bearing in a wall of said chamber opposed to said common wall, a pumping device in said housing provided with a drive shaft supported in, said bearings for sensitive axial movement, and means for urging said shaft axially thereof to hold said device against a portion of said housing opposite said common wall whereby said device is adapted to 'positively displace liquid through said housing, said common wall having means adapted to provide communication with said chamber to relieve pressure on the side of said device adjacent said common wall, and said urging means being` responsive to a back pressure in excess of a predetermined amount to permit movement of said device toward said common wall to reduce the pumping action thereof.

3. Pumping apparatus of the type described! comprising a pump housing having inlet and discharge connections, said discharge connection including a pressure chamber, a gas and liquid separating means including an expansion l chamber in communication with the atmosphere and in restricted communication with said pressure chamber, said pump housing and expansion chamber having a common wall, a bearing in said common wall, a drive shaft extending through said expansion chamber and said bearing into said housing and supported in said bearing for sensitive axial movement, pumping means secured to said drive shaft and movable therewith axially in said housing, means for resiliently urging said shaft axially toward a wall of said housing opposite said bearing, said means being responsive to a back pressure in excess of a predetermined amount to permit movement of said shaft along said bearing away from said opposite wall thereby to reduce pumping action of said pump. means providing a liquid return connection between said expansion chamber and the suction side of said pump, and liquid return control means responsive to a change in the liquid level in said expansionchamber for maintainingl said liquid level below said drive shaft.

-' y WILLIAM J. PETER.

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