US2935025A

US2935025A - Liquid fuel pumping apparatus

Info

Publication number: US2935025A
Application number: US268222A
Authority: US
Inventors: George W Wright; Joseph D Clymer
Original assignee: Tokheim Corp
Current assignee: Tokheim Corp
Priority date: 1950-09-26
Filing date: 1952-01-25
Publication date: 1960-05-03
Anticipated expiration: 1977-05-03

Description

May 3, 1960 e. w. WRIGHT ETAL 2,935,025

LIQUID FUEL PUMPING APPARATUS Original Filed Sept. 26, 1950 2 Sheets-Sheet 1 Resume Gasouus Hun KuocKGnsoL/mz INVENTOR5 Games: W'Wiwnr and y .1552? D.CLYMER May 3, 1960 s. w. WRIGHT ETAL H LIQUID FUEL PUMPING APPARATUS iii/ll!!! 2,935,025 LIQUID FUEL PUMPING APPARATUS George W. Wright and Joseph D. Clymer, Fort Wayne, Ind., assignors to Tokheim Corporation, Fort Wayne, Ind., a corporation of Indiana Original application September 26, 1950, Serial No. 186,815, now Patent No. 2,732,103, dated January 24, 1956. Divided and this application January 25, 1952, Serial No. 268,222

Claims, (Cl. 10387) This invention relates to a pumping apparatus for liquid fuel, such as gasoline, and more particularly to a pump and motor unit adapted to be mounted in submerged position in the fuel supply tank, and to thecombination of such unit with a mounting therefor. This application is a division of application Serial No.186,815, filed September 26, 1950, now Patent No. 2,732,103.

In the usual gasoline service station installation, the gasoline is drawn from an underground storage tank by suction through a suction pipe to a pump in a dispensing stand mounted above ground. That suction system presents a. number of difiiculties in handling modern hightest gasolines, and such difiiculties can be expected to worsen as new and more highly volatile gasolines come into use. Under the suction head, the highly volatile gasolines vaporize and boil in the suction pipe, especially under high temperature conditions. Vapor locks form in the-system,- to interfere with proper operation. The boiling of the gasoline tends to fractionate it, and the light fractions remain in gaseous form as the mixture passes through the pump to the dispensing line. Such vaporized light-ends must be eliminated by venting them to the atmosphere through an air separator. The gasoline delivered under these circumstances includes only the heavier fractions of the gasoline, and the light fractions are wasted. In such a system, it is essential to have an air separator, to insure metering. and delivery only of liquid gasoline and to prevent vaporized gas from passing through the meter and the dispensing line. More over, such systems require a pump at each dispensing stand, and for high efficiency of gasoline delivery, the pumps used are positive displacement pumps made with extreme accuracy, and with them the system requires a by-pass circuit to take account of normal variations and interruptions of delivery flow.

It is a primary object of this invention to provide a pump assembly, including a motor and pump unit and its mounting, adapted to be mounted in a standard gasoline storage tank with the pump unit in submerged position, so that the gasoline feeds to the pump under the static head of gasoline in the tank and is delivered from the tank under pump delivery pressure. It is an object of the invention to provide such an assembly in which the pump is an impeller pump, providing the characteristic advantages of such a pump. It is an object of the invention to provide a practical pump and motor unit which can be inserted in a supply tank through a standard-sized opening. and which will have sufficientcapacity to supply a plurality of dispensing stands. It is an object of the invention to provide such a pump assembly which will supply gasoline to dispensing. stands under pressure and thereby eliminate the necessity for air separation mechanism and for a pump by-pass circuit. It is an object of the invention to provide such an assembly which is both effective and safe for use with highly volatile gasolines, and to this end to provide adequate separation between the gasoline circuit and the electrical circuit, and to prevent the accumulationof dangerous explosive mixtures.

in accordance with the invention, an impeller pump, either a singleor a multi-stage pump, is direct connected to an electric motor of small physical size and especially of small diameter. The motor is preferably an induction motor, with no brush or commutator parts likely to spark. With a single-stage impeller pump, the motor is desirably a high-speed motor operable on high cycle current of the order of NEG-cycles per second, and the pump impeller is desirably mounted directly on and-carried by the motor shaft. Pump delivery passages are preferably formed about the motor, concentric therewith and in cooling relation thereto, and desirably terminate in a pipe fitting co-axial with the unit, for connection to a delivery pipe extending axially from the motor and by which the motor and pump unit may be physically supported. The motor itself is desirably confined in a motor compartment formed to contain a minimum of free space, and such compartment desirably communicates, as through a flame barrier, with an expansion-relief conduit which may also serve as an electric-supply conduit. The expansion relief and electrical conduit desirably extends axially through the fueldelivery pipe and is effectively separated and sealed from the fuel circuit. The expansion relief and electrical conduit is desirably connected outside the supply tank to a sealed junction box containing a free space of larger volume than that in the motor compartment, which serves as an expansion relief chamber for the motor compartmerit. The motor and pump unit and its supporting pipe are desirably carried by a' header or tank fitting adapted to be supported on a supply tank and to which gasoline delivery pipes can be attached, and the junction box which forms the expansion relief chamber'for the motor com-' partment is desirably carried by that same header and connected therethrough to the motor and pump unit.

The accompanying drawings illustrate the invention. In such drawings, Fig. l is a diagrammatic plan of a service station system having two gasoline storage tanks, as for regular and antiknock gasolines, and having two service islands each containing three dispensing stands, with two stands on each island connected to the regular-gasoline storage tank and one connected to the antiknockgasoline storage tank; Fig. 2 is a fragmental vertical section of a tank installation, showing a motor and pump unit in the tank and showing the delivery pipe header and electrical junction box located in a service. pit; Fig. 3 is an axial section of the motor and pump unit shown in Fig. 2, taken on the line 33 of Fig. 7; Fig. 4 is a side elevation of the motor and pump unit of Fig. 3, with parts broken away to show details of its assembly in a section taken on the line 44 of Fig. 7; Figs. 5 and 6 are respectively side and top elevations of the diffuser cup used in the structure of Fig. 3; and Fig. 8 is a ver tical section of the electrical junction box (and expansionrelief chamber) connected to the motor and pump unit in Fig. 2.

In the representative service station plan of Fig. 1, regular gasoline is stored in a storage tank 10, and this is connected by a delivery pipe 12 to dispensing

stands

13 and 14 at the ends of the upper service island, and by a delivery pipe 16 to the two dispensing stands 17 and 18 on the lower service island. Such' delivery pipes 12 and 16 are desirably connected to the pump unit header 20 through valves 21 and 22-. Antiknock gaso-- line is stored in the storage tank 30, and its pump header 32 is connected through valves 33' and 34, by supply pipes 35 and 36 to the middle dispensing stands'37 and 38 on the two service islands. Electrical motor-service lines and control-service lines are brought into the master switch and junction panel 40, the motor supply line is connected to the converter 42 to produce high-cycle motor operating current, and this is supplied to the pump headers" 20 and 32 throughwires in a supply conduit 44,

Control and lighting circuits are carried to the several dispensing stands through electrical conduits 46 shown in dotted lines.

The two pump headers and 32 are alike, and are desirably located in suitable service pits as shown in Fig. 2. As there shown, the supply header 20 is generally in the form of a pipe T carried by a flange mounted on the outlet fitting 48 of the tank 10. The header 20 carries a delivery pipe 49 which supports the motor and pump unit 50 and receives gasoline therefrom. The top wall of the header 20 is provided with a central opening to pass the electrical supply tube 52, which supports a junction box 54 connected to the supply conduit 44 and which also serves as an expansion-relief chamber as will be noted below.

Within the motor and pump unit 50 shown in Fig. 3, the motor is enclosed in a cylindrical motor housing 60 closed at its upper end by an integral wall 61 which supports a central sleeve 62 containing the upper hearing 64 for the motor shaft. The supply wires 66 for the motor pass through the wall 61 and through a pocket formed between an upstanding wall 68 and the bearing sleeve 62, and such wires are sealed in such pocket by filling it with sealing compound 69. The top wall of the bearing sleeve 62 is provided with a boss 63, bored to form an expansion relief passage, and this is closed by a flame barrier 65, as of sponge metal.

The lower end of the motor housing 60 is closed by an end plate 70 having a peripheral wall which is telescopically received within the open end of the cylindrical housing 60, and the two parts are sealed together by an annular gasket 71 which is compressed into sealing relationship with the parts as they are assembled. The end plate 70 supports a central sleeve 72 in which the lower bearing 74 for the-motor shaft is mounted. Such hear. ing 74 carries a radial load from the motor shaft 80, and in addition, its upper end is formed to provide a narrow annular thrust bearing land 76, engaged in thrust relationship by the fiat face of a hemispherical thrust bearing 77. Such hemispherical thrust member 77 is carried in a socket member 78 having a hemispherical seat and fixed on the motor shaft 80. The hemispherical member 77 has limited freedom of movement in its socket,

but is prevented from rotation with respect to the shaft by. a locating pin 79.

The two bearings 64 and 74, and the socket member 78 are desirably made of a carbon bearing-material requiring no periodic lubrication, and the shaft 80 and the hemispherical thrust bearing 77 are desirably made of stainless steel.

The upper end of the bearing-receiving sleeve 72 projects upward as a free-standing rim 82 for a considerable distance, and surrounds the thrust bearing socket 78. An inverted cup 84 is carried by the rotor with its walls positioned to form a depending skirt outside the upstanding rim 82, the interfitting assembly forming a flame barrier between the interior of the motor and the bearing.

The shaft 80 projects through an opening in the end wall of the bearing sleeve 72, and the pump impeller 90 is fixed directly on its lower end. Relative rotation of the two is conveniently prevented by providing the end of the shaft 80 with a squared shank and receiving such shank in a squared opening in the hub of the impeller 90. a

The lower end of the bearing sleeve 72 forms an annular socket about the shaft 80 for the reception of a stationary sealing member 86. This has a running fit with the shaft 80, and is sealed to the depending rim of the sleeve 72, as by a resilient annular gasket 87. A diametrical slot in the upper surface of the sealing member 86 engages a fixed pilot pin 88 to prevent rotation of the sealing member 86. a

The lower surface of the sealing member 86 forms an annular sealing land, and this is engaged by a ,corresponding land on a rotary sealing member 92. This is sealed to the shaft, as by a resilient annular gasket 93, and is spring pressed upwardly along the shaft, as by a plurality of circumferentially spaced springs 94 carried in suitable sockets in the hub of the impeller 90. The rotary sealing member 92 is non-rotatably fixed in a cup 95 from which one or more ears 96 are bent downwardly into engagement with a notch in the hub of the impeller 90, to insure rotation of the rotary sealing member 92 with the shaft 80.

The motor housing 60 and the end plate are secured together to form a self-contained motor unit. To this end, the lower end of the housing 60 is provided with a pair of diametrically opposite ears 97 overlying corresponding ears on the end plate 70, and the two parts are secured together by screws passed through the associated ears. Each of the parts also carries a second pair of ears 98 spaced from the first, and bored to receive a pair of bolts 99 by which the pump and motor assembly is secured together. The four ears on each of such members desirably support a peripheral locating ring 100.

The impeller 90 here shown is of the enclosed type, and generally conical in form with its open eye at the apex of its cone, so that flow through it is mixed-flow, with both radial and axial components of movement. It is provided with impeller blades 91 extending spirally from its eye to its periphery. The impeller thus discharges in a generally radial direction with considerable upward component, and the circle at which it discharges is smaller than the circumference of the motor housing 60.

The discharge from the impeller 90 is received by a diffuser formed by diffuser vanes 104 carried on the exterior of 'a dilfuser cup 106. Conveniently, there are four such diffuser vanes 104, and each terminates at its upper end in an ear 105 positioned to underlie the

ears

97 and 98, and two opposite ones of such ears 105 are bored to pass the assembly bolts 99. The diffuser cup lies between the end surface of the end plate 70 and the inner surface of the pump shroud of the pump assembly, and such inner surface forms the outer walls of the diffuser passages. Desirably the pump shroud 110 is provided with a circumferentially spaced series of radial vanes to prevent swirl of gasoline entering the eye of the impeller 90. The diffuser overcomes the swirl in the gasoline discharged from the rotor, and guides the flow in a'smoothly curved path terminating generally axially of the assembly.

From the diffuser, the gasoline flows upwardly in an I annular passage formed between the motor housing 60 and a casing sleeve 112, and passes from that passage into the upper cap 114 of the assembly. Such upper cap has an inner cup-shaped wall 116 telescopically received over the motor housing 60and sealed thereto by an annular gasket 118. The upper end of such inner wall 116 carries an upstanding boss 120 which is bored and counterbored and provided with two sets of concentric threads 122 and 124. The outer wall of the cap 114 is aligned at its lower end with the sleeve 112, and terminates at its upper end in a hub 126 threaded to receive and to be supported on the delivery pipe 49.

The sleeve 112 is suitably shouldered to lap the cap 114 and the locating rings 100; and the diffuser 106, the

. shroud 110, the sleeve 112, and the cap 114 are held in assembled relation by the pair of stud bolts 99 threaded into suitable bosses between the inner and outer walls of the cap114 and extending downwardly between the motor housing 60'and the sleeve, 112, through the

ears

98 and 105, and through the shroud 110, as shown in Fig. 4.

In mounting the motor and pump assembly for use, the hub 126 is threaded onto the supporting delivery pipe 49, a tube 128 is threaded into the threads 122 to receive the supply wires 66 for the motor, and a supporting and protecting tube 52 of larger diameter than the tube 128 is threaded into the threads 124 of the central boss 120.

, partments.

The pipe 49 and the two'tubes 128 and 130 extend upwardly to the pump header 20, and the upper end of the pipe 49 is threaded into the main body of the header 20. The two

inner tubes

128 and 52 extend on upward through the header 20 and through the opening in its top wall. The outer tube 52 is sealed to the header 20, as by'an annular gasket 132 lying in a groove in the header 20 and compressed into sealing engagement with the parts by a ring 133. The two tubes 128 and 130 are connected at their upper ends to the junction box 54. The outer tube 52 is threaded to the bottom boss 134 of the junction box 54 and provides the main support therefor. The inner tube 128 extends on upward into the junction box 54 through a collar 135 in which it has a slip fit. The supply conduit 44 is connected to a side boss 136 on the junction box 54, and at such connection, the box 54 is sealed with a suitable sealing packing 137. The top of'the junction box 54 is closed by a cap 138.

In this assembly there are a. number of separate com- The motor is contained in a compartment formed by its housing 60 and its endplate 70, which is completely closed and sealed at its lower end, and is open at its upper end only through the restricted expansion-relief opening containing the flame barrier 65. Its opening through that flame barrier 65 communicates with a second compartment defined by the inner wall 116 of the cap 114, and this compartment is completely closed and sealed at its lower end. It communicates through the interior of the tube 128 with the junction box 54, and such junction box 'is sealed. The inner tube 128 is protected by the concentric tube 130, which provides a secondary closure separating the electrical-supply and expansion-relief circuit from the gasoline circuit. The motor is thus completely enclosed save for expansion-relief communication with a closed electric-supply passageway, which terminates at its upper end in a completely closed junction box of a size which provides an expansion chamber of relatively large volume. The motor compartment contains very little free space-substantially less than the expansion chamberand may be filled either with air or with some inert gas, such as nitrogen. The motor is cooled by the flow past its walls of gasoline from the underground storage supply, and expansion of the small amount of gas contained in the motor compartment from any heat of operation is minimized by such cooling; and in any event such minimized expansion is dissipated by expansion-relief communication with the relatively large-volume expansion chamber in the junction box 54, located outside the gasoline storage tank.

The motor and pump unit described above is of small physical size and especially of small diameter, for ready insertion through the standard outlet opening of a standard tank. In an actual installation, the motor was an induction motor normally rated at horsepower (but actually about l-horsepower), having a synchronous speed on 400-cycle current of 12,000 revolutions per minute, and the combined motor and pump unit had an overall diameter of 3 /2 inches and an over-all length of about /2 inches, with other parts in proportion as shown in Fig. 3. Such unit delivered up to 45 gallons of gasoline per minute under a delivery head of lbs. per square inch.

The rate of gasoline delivery from any one dispensing stand to which the pump assembly may be connected will normally vary quite widely, from no flow to a full delivery rate of about 15 gallons per minute. Up to 6 dispensing stands may be connected to the same pump 59, and three of such stands may be operated simultaneously, so that the pump may be called on to deliver at varying rates ranging from no flow up to maximum delivery flow of about 45 gallons per minute.

In the operation of the pump, gasoline flows to it under the pressure of the static head in the supply tank. Gasoline enters the impeller 90 through its downwardly Open eye and flow thereto is guided by the radial vanes on the shroud 110. The impeller rotates at high speed, of the order of 10,000 revolutions per minute, and gasoline is discharged therefrom to the difiuser passages between the vanes 104 of the diifuser cup, where its direction of flow is straightened so that it is delivered generally axially upward to the annular passage surrounding the housing 60 of the motor. From here it flows up through the cap 114 to the supporting delivery pipe 49. At full demand of a plurality of dispensing stands, flow is at the maximum output of the pump, at a rate of about 45 gallons per minute, and the motor is under full load and drawing maximum energy. When dispensing delivery at one or more of the dispensing stands is throttled or shut off and delivery from the pump is consequently reduced; the pump continues in operation at pumping speed and maintains delivery pressure, but the load on the motor then decreases accordingly, with a corresponding reduction of the energy consumed by the motor. Under conditions of no flow, with the pump and motor still operating, the pump merely maintains the supply line full of gasoline under pressure, and the motor runs under minimum load, drawing a minimum amount of energy.

The mechanism shown in the drawings and described above is substantially that used in one of a number of actual service station installations, where the pump assembly is in successful commercial operation. It is highly effective in operation, and shows none of the difficulties normally encountered under similar conditions with the usual suction pumps heretofore in general use.

We claim as our invention: 1. A submersible pump-motor unit comprising a shaft, an'impeller mounted on said shaft, a casing surrounding said impeller and having openings formed therein for respectively. admitting fluid to said pump and discharging the same therefrom, a motor having a rotor member mounted on said shaft, a'frame assembly for said motor including a stator member surrounding said rotor member and mounted in an inner shell, means for attaching said casing to said frame assembly comprising an end shield rigidly attached to said frame assembly and having a plurality of projections each having an aperture formed therein, a flange formed on said casing and having a plurality of apertures formed therein, and a plurality of members respectively extending between end shield apertures and said casing flange apertures and into the same thereby rigidly to interconnect said end shield and said casing, and an outer shell surrounding said inner shell. and spaced therefrom defining a passage over said motor, said casing communicating with said passage whereby said fluid is pumped therethrough over said motor.

2. A submersible pump-motor unit comprising a shaft, an impeller mounted on said shaft, a casing surrounding said impeller and being open at both ends for respectively admitting fluid to said pump and discharging the same therefrom, a motor having a rotor member mount ed on said shaft, a frame assembly for said motor including a stator member surrounding said rotor member and mounted in an inner shell defining cavities at the ends of said stator member, a pair of end shield members respectively joined to said inner shell and closing said cavities, said end shield members respectively having bearings for rotatably supporting said shaft, clamping means for holding said motor in assembled relation, a third and outer end shield member abutting in part the one of said pair of end shield members which is remote from said impeller, an outer end flange overlying said outer end shield member and having an opening therethrough for discharging fluid from said unit, said casing abutting the end shield member adjacent thereto, clamping means engaging said casing and said outer end flange for holding said unit in assembled relation whereby said casing and end flange member may be disassembled without disassembling said motor assembly comprised by said frame assembly and said first-named pair of end shield,

members, and an outer shell surrounding said inner shell and spaced therefrom defining a passage over said motor, said outer shell being joined to said casing and said outer end'flange, said casing discharge opening and said outer end flange opening respectively communicating with said passage whereby fluid is pumped therethrough over said motor and out of said outer end flange opening.

3. A submersible pump-motor unit, comprising an electric motor of elongated cylindrical configuration having a central stator assembly and opposite end shield members containing shaft-supporting bearings and forming a self-contained motor unit defined externally by a substantially cylindrical surface, a motor shaft rotatably carried by said end members in said unit and projecting from one end thereof, a pump impeller mounted on said shaft, a pump casing fitted against said end of the motor casing and having a pump-discharge passage to discharge upward along the outer cylindrical surface of said motor, a mounting member fitted against the opposite end of said motor and having a fluid passage terminating in a fitting for connection to a supporting pipe to deliver fluid thereto and support the unit thereon, an outer shell surrounding the motor and spaced therefrom and extending between said pump casing and said mounting member I and defining a fluid passage along the motor surface from said pump-discharge passage to said mounting-member passage, and a plurality of tension members extending longitudinally through said fluid passage externally of said motor and within said outer shell and interconnecting said pump-casing and mounting member to hold sai unit in assembled relation.

4. A submersible pump-motor unit comprising a shaft, an impeller mounted on said shaft, pump casing means surrounding said impeller and having openings formed therein for respectively admitting fluid to said pump and discharging the same therefrom, a motor having a rotor member mounted on said shaft, a frame assembly for said motor forming a substantially cylindrical outer surface for said motor and including a stator member surrounding said rotor member, means for attaching said casing to said frame assembly comprising an end shield rigidly attached to said frame assembly and having a plurality of projections extending radially outward beyond said cylindrical surface and circumferentially spaced about the motor, each said projection having an aperture formed therein, said pump casing means having a plurality of apertures formed therein in axial alignment with said projection apertures, and a plurality of members respectively extending between end shield apertures and said aligned pump casing apertures and into the same thereby rigidly to interconnect said end shield and said casing, and a cylindrical outer shell surrounding said cylindrical motor surface and spaced therefrom outside said projections, said shell defining a passage over said motor and said casing communicating with said passage whereby said fluid is pumped therethrough over said motor.

5. A submersible pump-motor unit comprising a shaft,

an impeller mounted on said shaft, a casing surrounding said impeller and being open at both ends for respectively admitting fluid to said pump and discharging the same therefrom, a motor having a rotor member mounted on said shaft, a frame assembly for said motor including a stator surrounding said rotor member and a pair of end shield members respectively disposed at opposite ends of the frame assembly and respectively having bearingsfor rotatably supporting said shaft, said motor in assembled relation being defined by a substantially cylindrical outer surface, a third and outer end wall abutting in part that one of said pair of end shield members which is remote from said impeller and having a central conduit passage for electric supply means for said motor, an outer end flange overlying said outer end wall and having an opening therethrough for discharging fluid from said unit, said casing abutting the end shield member adjacent thereto, and an outer shell surrounding said motor assembly and spaced from the cylindrical outer surface thereof, said outer shell being joined to said casing and said outer end flange and defining a passage along the outer surface of said motor, clamping means for holding said motor in assembled relation and for releasably securing said casing and said outer end flange assembled to the opposite ends of the assembled motor and releasable therefrom without disassembling said motor, said clamping means including a plurality of circumferentially spaced tie rods extending longitudinally along the outer surface of said motor through said passage and within said shell, said casing discharge opening and said outer end flange opening respectively communicating with said passage whereby fluid is pumped therethrough over said motor between said tie rods and out of said outer end flange opening.

References Citedrin'the file of this. patent UNITED STATES PATENTS Re. 22,142 Ungar July 21, 1942 1,425,308 Woock et al Aug. 8, 1922 1,428,238 Keating Sept. 5, 1922 1,539,195 Kremser May 26, 1925 1,654,329 Hawley Dec. 27, 1927 1,742,208 Hawxhurst Ian. 7, 1930 1,872,111 Bricken Aug. 16, 1932 1,879,625 Mendenhall et al Sept. 27, 1932 1,896,328 Pohl Feb. 7, 1933 1,949,796 Himmel Mar. 6, 1934 2,217,746 Hawley Oct. 15, 1940 2,218,003 Hawley Oct. 15, 1940 2,320,708 Yost June 1, 1943 I 2,325,930 Avigdor Aug. 3, 1943 2,404,635 Hoover July 23, 1946 2,406,947 Harlamoif Sept. 3, 1946 2,430,509 Hoover Nov. 11,1947 2,492,141 Gaylord Dec. 27, 1949 2,518,597 Brooks Aug. 15, 1950 2,577,559 Armstrong et al Dec. 4, 1951