US3507582A - Centrifugal pump for a fuel tank - Google Patents

Description

April 21, 1970 c. W.JEEP, JR., ETAL 3,507,582

CENTRIFUGAL PUMP FOR A FUEL TANK Filed Aug. 30, 1968 INVENTORS CHARLES W. JEEP, 3?.

ROONEY W. DAViS ATTORNEY United States Patent O 3,507,582 CENTRIFUGAL PUMP FOR A FUEL TANK Charles W. Jeep, Jr., Webster Groves, and Rooney W. Davis, St. Louis, Mo., assignors to ACE Industries Incorporated, New York, N.Y., a corporation of New Jersey Filed Aug. 30, 1968, Ser. No. 756,643 Int. Cl. F04d 9/.00

U.S. Cl. 417--366 7 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The invention relates to a centrifugal fuel pump adapted to be submerged in the fuel tank of an automobile. Important desired characteristics of such fuel pumps are freedom from vapor lock, compactness, efficient cooling of the pump motor, simple structure and assembly, and unimpaired operation for an indefinitely long time without servicing. It is an object of the invention to meet these requirements to a greater degree than that achieved by previous in-tank fuel pumps. Vapor lock is likely to occur in such pumps because the gasoline tank is heated by the air blown back from the engine and by the mufiler and exhaust pipes, reaching temperatures considerably above the ambient temperature. Some vaporization of the fuel in the tank then takes place, especially since gasoline contains some light components which begin to boil below 100 Fahrenheit. As a result, a vapor bubble forms on the pump impeller and as the temperature rises the bubble becomes larger and larger until a point is reached where the pump no longer pumps fuel.

SUMMARY OF THE INVENTION A fuel pump is provided for mounting at the bottom of an automobile gasoline tank. It includes a direct current motor having a vertical axis. The motor casing is formed of a metallic cylinder fitted with end closure members made of plastic material and constituting the ends of a plastic pump housing. The end members provide bearings for the motor shaft and passages for fuel and vapor, and the upper end member houses the motor brushes and has nipples for receiving wires connected to the brushes. A centrifugal impeller is connected to the lower end of the shaft in a fuel receiving chamber in the bottom of the pump housing. The chamber provides clearance spaces around the impeller for enabling vapor separated from the fuel to pass around the impeller to its top side and then through an axial opening in the bottom of the housing. The housing has longitudinal internal ribs in which the motor casing fits tightly, and the ribs divide and seal the space between the motor casing and the pump housing into separate fuel and vapor passages. The fuel and vapor flowing along the motor casing serve to cool the motor.

The various components of the motor structure are so arranged and constructed that most of the major parts are simply placed one after another into the outer housing with no assembly operation other than the insertion of the parts. Final assembly and sealing is confined to the two relatively simple steps of sealing two major end closure elements to the outer housing after which an "ice outer cover and pump inlet cap is pressed into place at the lower end of the housing.

BRIEF DESCRIPTION OF THE DRAWING The invention is illustrated in the accompanying drawing, whereinz FIGURE 1 is a top plan view of the pump.

FIGURE 2 is a sectional view taken along line 2-2 of FIGURE 1.

FIGURE 3 is a partial section view along line 33 of FIGURE 1.

FIGURES 4 and 5 are half views of the top and the bottom of the impeller.

FIGURE 6 is a selective section taken along line 66 of FIGURE 2.

FIGURE 7 is an enlarged partial sectional view of the bottom of the pump.

FIGURE 8 is a section taken along line 88 of FIG- URE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The fuel pump, which may rest on the bottom of the fuel tank, as shown in Patents 3,090,318 and 3,294,025, has an outer housing 10 formed of a plastic material having a low affinity for the contaminants which may be present. One suitable plastic material is acetal resin. Housing 10 includes a long cylindrical member 12, a top member 14 and an inlet 16 at the bottom and a mesh screen or filter 18 for inlet 16. A rubber mount 20 may be fixed to the bottom of the fuel pump.

Within housing 10 is a direct current motor 22 having a commutator 24 and a permanent magnet stator 26. The upper portion 28 of the motor shaft extends into a bore of top end member 14, which provides a bearing for the shaft. Stator 26 is fixed in metallic cylinder 30, which is closed by the center portion 32 of top member 14 and by bottom closure member 34, which provides a bearing for portion 36 of the motor shaft. Member 34 at its upper end is snugly received by the inner surface of the lower end of casing 30. Member 34 is also provided with a supporting leg 34a and a supporting leg 3412. Since legs 34a and 34b are separate, they define an opening or openings 34c. Member 34 has a narrow slot 34 extending across on a portion of its upper end which slot defines a passage 35.

Top member 14 houses a pair of motor brushes 37, 38, which engage commutator 24, and a pair of conductors 39, 40 connected to the brushes. A nipple or outlet 42 for fuel and another outlet 44 for vapor are provided, the latter outlet having a cap 46. Top 14 may be sealed to housing 12 by a ring 48. Housing 12 is provided with three vertical ribs 51, 52 and 53, which extend from partition 54 to top member 14. The ribs are longitudinally serrated to form liquid and vapor tight seals against motor casing 30, which the ribs hold centered and spaced from housing 12. The spaces between housing 12 and casing 30 form separate channels or passages 56, 57, 58 for fuel and vapor. Top member 14 has channels 60 and 62 connecting passages 56 and 58 tooutlets 42 and 44.

At the bottom of casing 10 is a perforated plate 71 through which fuel from inlet 16 passes into pump chamber 66. Impeller has a hub 64 mounted on the end of shaft 36. The bottom side of impeller 70 has arcuate vanes 72 on a plate 74, and the top side has a ridge 76 and short peripheral vanes 78 outside ridge 76. Chamber 66 has a volute portion 80 and a volute outlet 82 through which the fuel flows upwardly into passage 56 and 60 to fuel outlet 42. Chamber 66 provides an adequate clearance space around impeller 70 for the movement of vapor. The centrifugal action of the impeller on the liquid fuel propels the fuel through volute 80 and outlet 82, but the vapor is forced by fluid pressure to rise to the top side of the impeller or chamber 66 and move into the low pressure area at the top center portion 84 of the impeller. The vapor then moves or bubbles out through opening 86 of partition 54, and then through space 340 of closure member 34. The vapor then rises through passages 57 and 58, channel 62 and outlet 44.

The operation of the fuel pump generally will be apparent from the foregoing description. The pump will be fixedly mounted on the bottom of a fuel tank by any suitable means. Fuel enters through filter 18 and passes through perforated plate 71 into pumping chamber 66. Vanes 72 on the bottom side of the impeller cause the liquid fuel to circulate and move outwardly and pass into volute section 80 and opening 82 and then upwardly through passage 56 to outlet 42, which of course is connected by a fuel line to the carburetor. In passing through passage 56, the fuel bathes a substantial portion of metallic casing 30 of the motor, and thus serves to cool the motor. A portion of the fuel (now under pressure) in channel 56 passes through the passage 35 in member 34 to rise upwardly through the interior of the motor to supply additional cooling thereto. This portion of the upwardly rising fuel passes out of the motor enclosure by way of clearance in the bearing surrounding portion 28 of the motor shaft, thence upwardly through restriction 15 and out through the top member 14. Vapor in the fuel moves through the clearance space around impeller 70 and rises to the top side thereof. Liquid fuel tending to flow around to the top side of the impeller is returned by the short peripheral vanes 78 on the top side, and ridge 76 acts as a barrier to flow of liquid over the top side of the impeller. The vapor, however, moves along the top of chamber 66 and passes over barrier 76 of the impeller and then out through openings 86 and 88, passages 57 and 58, and is returned to the fuel tank through outlet 44. In passages 57 and 58 the vapor moves along motor casing 30 and helps to cool it.

It is to be mentioned that leg 34a of member 34 has sufiicient length to bridge across the space between ribs 51 and 52 thereby enclosing so much of passage 56 as is defined by member 34. Casing 30 defines the remainder of passage 56.

Assembly of the motor-pump is easy and simple. The rotor is slipped inside the stator 26 which already includes the casing 30. Bottom member 34 is slipped onto the lower end of the rotor shaft and top member 14 is slipped onto the other end. The foregoing sub-assembly is then forced into the housing 12 until the member 34 comes to rest on the partition 54. Forcing the casing 30 into the housing 12 is necessary because there is an interference fit with the ribs 51, 52 and 53' which forms the seal referred to earlier. Subsequent assembly operation includes installation of the impeller 70, and the perforated plate 71. Plate 64 is secured in place by rolling the edge of the housing over the plate, as by applying heat. The inlet cap is then pressed into position. If a press fit is used, the inlet cap need not be otherwise secured. A final assembly operation is the installation of securing ring 48 which can be heat sealed or glued in place. This completes the major portion of the assembly operation. The electrical lead wires and brushes can be installed at any suitable time in the operation.

We claim:

1. An electric fuel pump for use in a liquid fuel tank comprising:

(a) an electric motor adapted to be mounted vertically and having a shaft extending downwardly therefrom,

(b) a centrifugal impeller mounted on the shaft,

(0) an elongated cylindrical housing of plastic material enclosing said motor and impeller, said impeller including a circular plate having a plurality of outwardly extending vanes on the bottom of said plate,

(d) means for obstructing radial flow of liquid fuel along the top of said plate,

(e) said housing having a fuel inlet passage extending to the bottom of said impeller and a fuel outlet adjacent the periphery of the impeller, said housing also providing a passage for vapor round the impeller from the bottom portion thereof to a central portion of the top of the impeller, and

(f) an outlet passage extending upwardly through the housing from the central portion of the top of the impeller for emitting vapor separated from the fuel by the impeller.

2. A pump according to claim 1, wherein said housing has a plurality of internal, vertically extending ribs, a cylindrical metallic casing surrounding said motor located within said housing and tightly engaging said ribs, the space defined by the portions of the walls of the housin and casing between two said ribs forming a passage communicating with said outlet passage for the vapor, and another space defined by other portions of the walls of said housing and casing forming a fuel passage communicating with said fuel outlet.

3. A pump according to claim 2, wherein said casing for the motor extends along a major portion of the passages defined =by said ribs, whereby the vapor and fuel flowing through the passages cool the motor.

4. An electric pump according to claim 3, comprising a member for closing the bottom of said casing for the motor, said member having a close-fitting bearing for the motor shaft, said member having a partition extending between two of said ribs for separating the fuel passage between these ribs from the passage for the vapor.

5. An electric pump according to claim 4, comprising a plastic top member adapted to fit on the top of said housing and having a lower portion engaging and closing said casing for the motor, said top member having a pair of vertical openings for a pair of motor brushes, said top member having also a bore for an upper portion of the motor shaft and separate outlets for vapor and fuel.

6. An electric pump according to claim 1, wherein said means for obstructing radial flow of liquid fuel along the top of the impeller plate includes a closed annular ridge on the top of said plate.

7. An electric pump according to claim 6, including a plurality of vanes on the top of said plate extending from said annular ridge to the periphery of said plate.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner US. Cl. X.R. 417-424

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