US2671409A - Direct-drive gasoline dispensing pump - Google Patents

Description

Ch 1954 e. w. WRIGHT -DRIVE GASOLINE DISPENSING PUMP DIRECT 2 Sheets-Sheet 1 Filed Aug. 1, 1950 Patented Mar. 9, 1954 DIRECT-DRIVE GASOLINE DISPENSING PUMP George W. Wright, Fort Wayne, Ind., assignor to Tokheim Corporation, a corporation of Indiana Application August 1, 1950, Serial No. 177,075

8 Claims.

This invention relates to gasoline dispensing apparatus of the type commonly installed at automobile service stations, and especially to a direct-driven pump for use therein, and to dispensing apparatus embodying such pump.

Heretofore it has not been found possible in a practical gasoline dispensing stand to connect a rotary pump directly (coaxially) to its driving motor. Such a direct coaxial connection, how ever, would substantially reduce the power required and would save precious space in the stand housing. It would eliminate power transmission mechanism and the bearings necessary to maintain operating alignment of the pump under the side-thrust resulting from indirect power transmission, would substantially eliminate transmission losses, and would permit the use of a smaller motor, or greater pump capacity.

The impracticability of a direct-driven pump has resulted from a number of factors. Not only is space extremely limited in a commercially acceptable dispensing stand, but the horizontal dimensions thereof restrict the length of any horizontal direct-drive arrangement. Vertical arrangements have been suggested, but they raise difficult thrust problems which are especially troublesome in a close-fitting pump. Safety requirements and regulations require that gasoline and strong gasoline fumes be prevented from entering the motor. The sealing problem is difficult in a gasoline pump even where ample space is available, especially in view of the widely varying conditions of operation and of the necessity to maintain the system full of liquid and free of air. The space and length limitations on a di- 3 rect-drive combination leave little or no room for seals. Moreover, in gasoline dispensing equipment it is essential not only to seal the pump against escape of gasoline, but also to prevent ingress of air, and this has limited the usable sealing means.

The rotary pumps used in gasoline dispensing stands normally require relatively slow-speed operation, usually at about half of standard motor speed, and from a practical viewpoint they have no lubrication save from the gasoline which they pump. They require unusually close-tolerance fits and accurate maintenance of alinement. The increased speed of a direct-driven pump tends to raise lubrication problems, and to increase the sealing problem, both directly and through pressure increases and higher wear rates.

It is the object of my invention to provide a practical direct-drive pump and motor combination for gasoline dispensing stands, which Will meet the critical space and length requirements, which will satisfy the safety requirements, and which will be practical both for manufacture and in use. It is a further object of my invention to provide a direct-drive pump in which both the escape of gasoline and the entrance of air is effectively avoided and in which gasoline is effectively prevented from entrance to the directconnected motor.

In accordance with my invention, I mount the rotor of a rotary pump directly on the projecting (forward) end of the motor shaft, and support the pump casing thereof directly on the motor frame. I prefer to use a Viking type pumpin which a pinion is mounted eccentrically within the projecting teeth of a crown gear-and prefer to use the crown gear thereof as the rotor which is mounted on the motor-shaft; but the pinion can be so mounted instead, and other types of rotary pumps can also be used. Preferably, I dispose the pumping elements of the shaftmounted rotor at the front of the rotor and arrange the intake and discharge passageways of the pump casing circumferentially about the shaft-mounted rotor and in radial communication with the rotor compartment.

In view of the relatively high speed of directdrive operation, I preferably reduce somewhat the displacement of the pump. However, such reduction need not be in proportion to the speed increase over a belt pump, and instead, the pump may have greater capacity than such prior pumps. I find it of advantage to make the displacement reduction by reducing the axial length of the rotor teeth and of their meshing pinion, rather than by reducing the radial dimensions of the parts from those of prior belt-driven pumps.

Between the pumping elements and the point at which the shaft projects from its bearing in the motor frame, I preferably provide in series: first, a close-running fit area between the rotor and the casing; second, an equalizing chamber; third, a thrust bearing between an annular radial face on the shaft-mounted rotor and a mating annular face on the inner wall of the pump casing; fourth, a rotary seal, which may have unidirectional sealing characteristics, comprising a pair of rotary-seal members spring-pressed together in the direction of leakage tendency; and fifth, a slinger-ring on the shaft and in a space which is drained to a low-pressure area-to atmosphere or to the suction side of the pump below the check valve. I desirably position a shaft bearing rearward from the slinger ring and arrange its lubrication so that any lubricant leak or seepage from such bearing toward the rotary seal will be from the opposite side of the slinger ring. In combination with the spring-pressed rotary seal, arranged to seal against gasoline escape, I provide a check-valve in the intake passageway of the pump casing to avoid reversal of leakage tendency at such rotary seal.

A dispensing stand installation embodying my invention will include the pump, connected by a suction line to a gasoline storage and supply tank, usually underground, and connected to deliver to and usually to maintain pressure in the dispensing line of the stand. The dispensing line of a retail stand will normally include an air separator, a meter and its associated computer, a delivery hose, and a nozzle, and flow therethrough will be controlled by a manually operable valve in the nozzle.

The accompanying drawings illustrate my invention: In such drawings, Fig. 1 is a vertical section showing a dispensing stand and its contained apparatus and showing an underground storage tank and pipe connections therefrom to the stand; Fig. 2 is a longitudinal section on the line 2-2 of Fig. 3 through a combined pump and motor unit embodying my invention; Fig. 3 is a transverse section taken on the line 3-3 of Fig. 2; and Fig. 4 is a fragmental section similar to Fig. 2, and showing a modified arrangement in which the leakage drain conduit is connected to the suction side of the pump below the check valve.

In the dispensing apparatus shown in Fig. 1, a buried storage tank Ill is connected to the pump [4 of the dispensing stand H; by a suction pipe I2, which may have a screen at its lower end. The pump discharges through a pipe I8 to a combined air separator and meter 20 from which air is discharged to an air eliminator 22 vented to atmosphere through a vent pipe 24. Liquid gasoline carried over into the air eliminator 22 is returned to the suction side of the pump through a pipe 26. The meter mechanism of the combined air separator and meter 26 is connected through a gear case 28 to the drive shaft of a computer and register 39, which may be of conventional construction. The airseparator and meter 29 shown is of the type covered in the copending application, Serial No. 166,038, filed June 3, 1950, in which I am joint applicant with Robert J. Jauch and Joseph D. Clymer. I prefer this type, but other air-separation and meter arrangements may be used. The main stream of gasoline from the air separator and meter 2!] is discharged through a pipe 32 leading from the bottom of the meter upwardly to a visible gauge 34 located at the top of the dispensing stand I5. From this gauge 34 the gasoline passes through a pipe 86 to the delivery hose 38, through which it is dispensed under control of the control valve 49 of the nozzle 42. The pump is driven by an electric motor M controlled by a switch actuated in the usual way upon removal of the nozzle 42 from its supporting bracket 46.

In such dispensing apparatus, the pump and the dispensing line leading therefrom should be maintained full of liquid, so that it is always ready for immediate dispensing operation, and to insure accurate metering of the dispensed liquid.

The dispensing stand I6 and the mechanism it contains as shown in Fig. 1 is ordinarily assembled as a unit by the manufacturer, and is installed as a unit at the service station, where its pump It is connected to the piping I2 and tank In installed by the service station owner in readiness for the dispensing stand assembly.

The pump unit as shown in Figs. 2 and 3 comprises an electric motor 44, which may be of standard construction and operates at the standard speed of about 1750 R. P. M. The end housing 52 of such motor 44 is formed to cooperate with the pump casing 54, and the motor shaft 55 is journaled therethrough in a suitable sleeve bearing 58. The outer end of the end housin 52 is formed to provide an annular mounting face 68 and a forwardly projecting cylindrical boss 62, with one or more narrow annular shoulders 64 adjacent the base of that boss 62. The pump casing 54 comprises a central sleeve 65 having a cylindrical bore of a size adapted to be received upon the cylindrical boss 62 of the motor end-plate 52, and at its rear end such sleeve 56 is provided with a mounting flange 68 and a stepped internal form adapted to provide a shoulder I8 opposite the shoulder 64 on the end-plate 52 and spaced therefrom to provide a ring-shaped gasket-receiving space, desirably of rectangular cross section. A toroidal gasket 12 is received within such gasket space, to seal the pump casing to the motor end-plate. Such gasket 12 is desirably of resilient gasoline resistant material such as synthetic rubber and is of circular cross section with a section diameter greater than the dimensions of such rectangular gasket space, so that it is yieldingly deformed into sealing engagement with the walls of such channel when the parts are assembled.

The motor shaft 56 extends through and beyond the boss 82 of the motor end-housing 52, and its outer end carries a pump rotor keyed to the shaft. The rotor 86 has on its rear face a central hub 8! and on its front face a circumferential series of forwardly projecting crown teeth 82, generally of part-cylindrical shape. Within the ring gear formed by such teeth 82 there is a pinion 84 meshing with the teeth 82 of the rotor 80. The pinion 84 is of smaller size than the rotor 85 and is mounted eccentrically with respect thereto on a stub shaft 86 carried by the end plate 88 of the pump. Between the two gears, opposite their meshing point, there is a crescent shaped filler 90 conforming on its A inner surface to the path of the ends of the pinion teeth, and on its outer surface to the path of the inner ends of the crown teeth 82. Such filler 90 is carried by the end plate 88, desirably integral therewith.

The front face of the rotor 80 may be provided with a pair of threaded holes SI for attachment of a puller tool to remove the rotor 80 from the motor shaft 56.

Immediately behind the tooth portion of the rotor 80, axially between the teeth 8'. and the hub 8I, there is an intermediate portion 83 having a circumferentially continuous cylindrical surface. Such surface has a close running fit with the wall of the sleeve 66, and such close fit tends to prevent flow of pressure liquid from the outlet chamber I22 rearward along the walls of the rotor compartment, and likewise tends to prevent flow from behind the rotor to the intake chamber I 20.

The space behind this intermediate portion 83 of the rotor, between the hub BI and the surrounding sleeve 66, forms an equalizing chamber 85, exposed both to leakage under pressure from the outlet chamber I 22 and to leakage under suction to the intake chamber I20. In operation.

such chamber 85' is normally at elevated pressure. however, which partially balances end thrust of the rotor.

The rear end of the hub M of the rotor 36 an annular radial thrust face 04 in bearing engagement with a mating thrust face 96 on the boss 62 of the motor end-plate 52. The interengaging annular thrust faces 94' and 66 have sealing characteristics, especially when under thrust load, and tend to resist leakage from the chamber 85 to the shaft.

Within the annular face 94, the hub BI is counter-bored to receive the rotating member I of a rotary seal. Such sealing member I00 has a slip fit on the shaft 56, and is movably sealed thereto by a toroidal gasket I03 received in a rectangular rabbet groove in the inner corner of the sealing member. A plurality of circumferentially spaced bores in the hub BI behind the sealing member I00 provide seats for a plurality of springs I06 to urge the member I 00 rearward along the shaft 56. To insure rotation of the sealing member I 00 with the rotor 80, such member I 00 is provided with one or more pins I04 received in short holes in the rear face of the rotor 80.

Opposite the sealing member I00 and within the thrust face 96, the boss 62 is provided with a shouldered counterbore to receive the stationary sealing member I02, and such sealing member I02 is shouldered in cooperation therewith to form a rectangular groove for the reception of a toroidal gasket I05 sealing the member I02 to the boss 62. To prevent rotation of the sealing member I02, the boss 62 is provided with a projecting pin I08 to interengage a lug on the rear face of the sealing member I02. The two sealing members I00 and I02 have interengaging annular sealing faces, and the member I 00 rotates with the rotor 80 and the member I02 is held stationary with the motor boss 62.

The rear end of the sealing member I02 is spaced from the bottom of the counterbore of the boss 62, to provide a collection chamber I09, and within such chamber, the shaft 56 carries a slinger ring H0. The annular chamber I 09 is provided with a free drain passage II2, of fairly large cross sectional area and leading directly downward. To avoid back pressure in such drain passageway II2, it is either open to the atmosphere as shown in Fig. 2, or may be connected tothe suction side of the pump below the check valve, as shown in Fig. 4. When it is so connected, I prefer to include a glass sight tube H4 in the connection.

About the cylindrical sleeve 66, the pump casing forms an inlet chamber I and an outlet chamber I22, generally on horizontally opposite sides of such sleeve 66. In the upper right quadrant of the sleeve 66, the inlet chamber I20 communicates with the rotor chamber through a port I24 which opens to the rotor chamber from the circumference thereof and over an arc of about 90 extending from the top of the rotor chamber clockwise to a point overlapping one end of the filler 90. The rotor chamber communicates with the outlet chamber I22 through an opposite port I26 extending through substantially a 90 arc and overlapping the opposite end of the filler 90.

Below the inlet chamber I20, the pump casing is formed to receive a removable cylindrical filter screen I30.

Intake to the pump casing from the suction pipe I2 is through a laterally-extending transfer passage I34. At the opposite end of; such passage I34 from the suction pipe, the bottom wall of the casing is bored to pass a check valve cage I36, and the inner wall I35 is bored to provide a seat for that cage I36. The cage is conveniently sealed to the two walls by toroidal gaskets I31 and I38, and the outer wall opening is closed by a plate I39.

The cage I36 is a cylindrical sheet metal stamping having inlet openings in its cylindrical wall and forming a valve seat at its upper end. The stem I44 of the check-valve I42 is received in a sleeve in an apertured plate I40, and a spring I46 acting between such plate I and a retainer I48 on such stem I44 urges the valve toward closed position.

The stem I44 of the valve may be provided with a relief valve. For this, a shouldered hole is bored in the stem I44 to provide a bleed passage and a valve seat I50, and a valve ball is seated therein. A spring I52 supported by a pin at the lower end of the stem normally holds the ball on the seat I50.

At the top of the casing, the inlet and outlet chambers are separated by a common vertical wall I60, through which there is a check valve port I62 having a seat at the low-pressure side of the wall. Opposite such port, in the outlet chamber I22, there is a bored boss I63 to guide the stem I64 of a check-valve I65. Such valve I65 is urged to closed position by a spring I66 bearing against a plug I61 through which the valve I65 may be inserted and removed.

The pump casing required for the arrangement described above is not only compact and relatively simple to manufacture, but it requires but little extra length beyond that required for the motor and pulley in the usual belt-drive arrangement.

In a usual dispensing installation, such as that shown in Fig. 1, the pump I4 has considerable suction lift from the tank I0 through the suction pipe I2, and delivers through the dispensing line under control of the nozzle valve 40. The conditions of operation of the dispensing equipment vary widely. The motor and pump are in continuous operation throughout each dispensing cy-. ole, and in any such cycle, flow conditions will vary from full delivery through the nozzle 40 to full by-pass through the valve I 62. Under all conditions, both during operation and during stand-by periods between dispensing cycles, the dispensing line should be maintained full of liquid, and in some dispensing apparatus is maintained under pressure. With my pump, the system normally includes no foot valve in the tank, and th check valve I42 serves to maintain the dispensing line full of liquid and to maintain prime in the pump, and may also maintain the dispensing line under pressure where that is desired. The pressure responsive valve I controls any pressure in the dispensing line and in the pump, and relieves any undue pressure such as may occur from a rise in temperature.

With the pump in operation, pressure builds up in the outlet chamber I22, which tends to cause leakage flow rearward along the walls of the sleeve 66, past the close fitting surface 83 of the rotor 60, to the equalizing chamber 85. At the same time, suction in the inlet chamber tends to cause leakage flow along other portions of such sleeve 66 in the opposite direction, from the chamber to the intake chamber I20. The equalizing chamber 85-, however, normally operates under elevated pressure, which reduces end 7 thrust otherwise carried by the thrust faces 94 and 98.

The thrust faces 94 and 90 take the thrust from the rotor and prevent such thrust forces from being exerted on the rotary seal members, and their close running fit tends to retard leakage from the equalizing chamber 85 toward the rotary seal members. The rotary seal-members I00 and I02 are maintained in sealing engagement by relatively light spring pressure from the springs I06, and normally during operation are additionally urged together by the pressure of gasoline which leaks past the thrust faces 94 and 90.

Such rotary seal members I00 and I02 are highly effective to seal the pump against escape of gasoline, especially under the operating conditions described above. Moreover, any leakage which may occur through such rotary seal will be thrown from the shaft 56 by the slinger ring H0, and will drain immediately from the surrounding chamber I09 through the drain passageway II2, either to the air or to the suction side of the pump. Any leaking gasoline will therefore be effectively prevented from entering the 1 motor. Any lubricant which leaks out the end of the motor bearing 58 will likewise be thrown from the shaft H0 and will likewise be drained through the drain passageway I I2.

When the pump is stopped, leakage tendencies may change substantially, and in prior dispensing apparatus the leakage tendency at the pump seal tends to be reversed in view of the suction head in the suction pipe, specially when the column of liquid in such pipe is partially vaporized from the reduced pressure. Such reverse leakage tendencies at the sea1 are avoided in my pump by the check valve I42, which isolates th seal from the effects of such static suction head, and maintains an outward leakage tendency at the seal, in the direction in which such seal is highly effective. The check-valve thus not only replaces the usual inaccessible foot-valve, but cooperates to mak the rotary seal effective; and the combination permits the compactness and short length required by the space limitations of dispensing equipment.

I claim as my invention:

1. Gasoline dispensing apparatus, comprising a motor and a direct-mounted pump, said motor having a shaft bearing and a motor shaft projecting therethrough, a pump-rotor carried by the projecting shaft, a pump casing about said rotor and forming an equalizing chamber behind said rotor, means forming an inlet passage having a suction intake opening, a rotary seal about said shaft at its entrance to said equalizing chamber and including a pair of seal ing members having aXially-interengaging annular sealing faces, one of said members being sealed with respect to said shaft and the other with respect to said casing, means yieldingly urging said members into sealing interengagement, a thrust bearing having sealing characteristics interposed between said equalizing chamber and said rotary seal, said rotor having a running fit portion separating said equalizing chamber from the pressure and suction areas in said pump, leakage through which tends to maintain said equalizing chamber at elevated pressure during operation of the pump and to create an elevated pressure acting on said seal in parallel with said yielding means, a slinger ring on said shaft between said motor bearing and said rotary seal, a collecting chamber formed about said slinger ring,a drain passageway for liquid thrown from said shaft by said slinger ring, said drain passageway being maintained at a pressure not exceeding atmospheric pressure, and a check-valve in the suction side of said pump and isolating said seal from exposure through the working elements of the pump to static suction at said suction intake when the pump is idle.

2. Gasoline dispensing apparatus, comprisin a motor having a bearing and a shaft projecting therethrough, a pump rotor carried by said shaft and having a working portion, a casing formed about said rotor and having an inlet passage leading from a suction intake opening to the working portion of said rotor, there being in series along the leakage path from said working portion to said bearing: a running fit portion on said rotor, an equalizing chamber, a thrust bearing including annular thrust faces which interengage in leak resisting engagement, a rotary seal including a stationary sealing member having an annular sealing face and a rotary sealing member sealed to said shaft and yieldingly urged into rotary sealing engagement with said stationary sealing member, a slinger ring on said shaft, and means to freely drain liquid thrown from said slinger ring.

3. Gasoline dispensing apparatus, comprising a motor having a bearing and a shaft projecting therethrough, a pump rotor carried by said shaft and having a Working portion, a casing formed about said rotor and having an inlet passage leading from a suction intake opening to the working portion of said rotor, there being in series along the leakage path from said working portion to said bearing: a thrust bearing in cluding annular thrust faces which interengage in leak resisting engagement and a rotary seal including a stationary sealing member having an annular sealing face and a rotary sealing member sealed to said shaft and yieldingly urged into rotary sealing engagement with said stationary sealing member, and a check-valve in said inlet passage closing in the direction of leakage from said rotary seal to said suction intake opening.

4. Gasoline dispensing apparatus, comprising a motor and a direct-connected positive-displacement pump having a rotor carried by the shaft of said motor, a dispensing line connected to said pump and normally maintained full of gasoline, a pump casing, means forming an inlet passage for said pump and leading from a suction intake opening, a rotary seal for said shaft. between said rotor and motor and having unidirectional pressure-responsive sealing characteristics acting to prevent escape of fluid from said pump toward said motor, said seal being exposed at its motor-end to a pressure not exceeding atmospheric pressure and being exposed at its pump end to elevated pressure during operation of the pump, and a check valve in said inlet passage isolating said rotary seal from exposure through the working elements of said pump to static suction at said suction intake when the pump is idle.

5. Gasoline dispensing apparatus, comprising a motor, a pump casing forming a cylindrical rotor chamber and an inlet and outlet passage in communication therewith, a dispensing line connected to said outlet passage and normally maintained full of gasoline, said inlet passage being adapted to be connected to a suction pipe, a shaft driven by said motor and extending 9 through a wall of said rotor compartment, a rotor on said shaft having a circumferentially continuous surface in close-running relationship with a circumferentially continuous surface of said rotor compartment, said close-running surfaces being disposed between the pump elements of said rotor and the point at which said shaft enters said rotor chamber whereby the closerunning relationship therebetween restricts leakage from the inlet and outlet sides of said pump from and to said entrance point, a rotary seal about said shaft at its entrance to said rotor chamber and including a rotatable sealing member sealed to said shaft and yieldingly urged into rotary sealing engagement with a complementary seal, the sealing force thereof being arranged to act in the same direction on said rotary sealing member as the pressure within said pump, and a check-valve in said inlet passage closing in the direction of leakage flow from said rotary seal to said suction pipe.

6. Gasoline dispensing apparatus, comprising a motor and a direct-mounted pump, said motor having a shaft bearing and a motor shaft projecting therethrough, a pump-rotor carried by the projecting shaft, a pump casing about said rotor and forming an equalizing chamber behind said rotor, means forming an inlet passage having a suction intake opening, a rotary seal about said shaft at its entranc to said equalizing chamber and including a pair of sealing members having axially-interengaging annular sealing faces, one of said members being sealed with respect to said shaft and the other with respect to said casing, means yieldingly urging said members into sealing lnterengagement, a thrust bearing having sealing characteristics interposed between said equalizing chamber and said rotary seal, a slinger ring on said shaft between said motor bearing and said rotary seal, a collecting chamber formed about said slinger ring, and a drain passageway 10 for liquid thrown from said shaft by said slinger ring, said drain passageway being maintained at a pressure not exceeding atmospheric pressure.

'I. Gasoline dispensing apparatus, comprising a motor enclosed at one end by a housing end-plate having a shaft bearing through which a motor shaft is journaled, a pump casing forming a cylindrical rotor chamber closed at one end by said end-plate, a pump rotor on said shaft and including a circumferentially continuous portion having a running fit with the Wall of said rotor chamber, gear-type pump elements on said rotor on the opposite side of the running-fit portion thereof from said motor, a non-rotary sealing member sealed to said end plate and having a radial seal face disposed toward said rotor, a rotary sealing member sealed to said shaft and having a seal fac in sealing engagement with said non-rotary sealing member, means to supply lubricant to said bearing, a slinger ring carried by said shaft between said non-rotary sealing memher and said bearing, a collection chamber about said slinger ring, and a free drain passageway from said collection chamber.

8. A gasoline dispensing pump as defined in claim 6 in which said drain passageway is connected to the suction side of said pump.

GEORGE W. WRIGHT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,597,411 Kinney Aug. 24, 1926 1,902,077 J aworowski Mar. 21, 1933 2,384,254 Meredew Sept. 4, 1945 2,525,619 Roth Oct. 10, 1950 FOREIGN PATENTS Number Country Date 587,684 Great Britain 1947

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