US3743438A

US3743438A - Transfer pumps

Info

Publication number: US3743438A
Application number: US00227567A
Authority: US
Inventors: H Colliver; G Boby; D Farmer
Original assignee: Plessey Co Ltd
Current assignee: Plessey Overseas Ltd
Priority date: 1972-02-17
Filing date: 1972-02-17
Publication date: 1973-07-03
Anticipated expiration: 1990-07-03

Abstract

In order to enable a fuel transfer pump constructed as an axialflow impeller pump to remain effective to a very low fuel level in a tank, the axis of the pump is arranged at an angle to the vertical so that the impeller inlet face forms an angle with the tank bottom. Preferably the impeller projects below the lower end of a shroud housing, the edge of the projecting impeller portion and the end surface of the shroud is tapered to have a tangential plane parallel to the tank bottom.

Description

United States Patent 1 Colliver et al.

[ July 3,1973

[ TRANSFER PUMPS [75] inventors: Harold Edward Sydney Colliver;

Gerald Eric Boby; Dennis Dewhurst Farmer, all of llford, England [73] Assignee: The Plessey Company Limited,

Ilford, England 22 Filed: Feb. 17,1972

21 Appl. No.: 227,567

Related US. Application Data [63] Continuation of Ser. No. 30,698, April 22, 1970,

abandoned.

[52] US. Cl 415/204, 415/219 R, 222/385, 417/424 [51] Int. Cl F04d 29/40, B67d 5/48 [58] Field of Search 415/213, 215; 2/204, 2/206; 417/231, 424; 222/385; 250/7, 42, 97

[56] References Cited UNITED STATES PATENTS 536,998 4/1895 Bennett 416/189 2,214,677 9/1940 North 417/231 2,698,583 1/1955 House et al.. 417/231 2,860,835 11/1958 Schade 417/424 3,148,464 9/1964 Jones 37/67 Primary Examiner-Henry F. Raduazo Attorney-Harold 1. Kaplan [5 7 ABSTRACT ln order to enable a fuel transfer pump constructed as an axial-flow impeller pump to remain effective to a very low fuel level in a tank, the axis of the pump is arranged at an angle to the vertical so that the impeller inlet face forms an angle with the tank bottom. Preferably the impeller projects below the lower end of a shroud housing, the edge of the projecting impeller portion and the end surface of the shroud is tapered to have a tangential plane parallel to the tank bottom.

12 Claims, 1 Drawing Figure PAIENIEDJUL 3 I973 3. 743,438

TRANSFER PUMPS This a continuation of application Ser. No. 30,698, filed Apr. 22, 1970.

DISCLOSURE This invention relates to fuel-transfer pumps. A fueltransfer pump serves to withdraw fuel from a fuel tank and deliver it to a place of consumption, for example to the fule pump of a combustion engine, generally with the interposition of a further so-called backing pump which serves to raise the pressure level of the fuel entering the fuel pump proper. It is an object of the present invention to provide an improved transfer pump which can effectively deal with the transfer of liquid from a tank even when the liquid level in the tank is very low. A known kind of transfer pump is of the axialflow impeller type and is arranged in a fuel tank with its axis vertical, the impeller being accommodated in a shroud, and while this kind of pump works satisfactorily so long as the fuel level is reliably above the lower end of the shroud in which the impeller is accommodated, its effectiveness ceases when the fuel level falls below the fuel-entrance end of the shroud, Since the entrance end of the shroud must be spaced from the bottom of the tank sufficiently not to obstract the access of liquid to the impeller inlet, a certain amount of fuel, determined by the level of the entrance end of the shroud, cannot be withdrawn from the tank by the known pumps.

The present invention has for a more specific object to make it possible to withdraw liquid from the tank down to an appreciably lower level. According to the invention the transfer pumpo is an axial-impeller pump in which the entrance-end face of the shroud is inclined at an angle to the bottom of the tank, with a complementary inclination of the axis of the impeller, thus ensuring that, even if the impeller end face approaces the tank bottom very closely at one side, the access of liquid to the entrance of the impeller and shroud is relatively free since, due to the inclination of the entrance face, the mean amount of spacing between the impeller end face and the tank bottom is relatively large with the spacing increasing from a point of closest approach to the diameterically opposite point.

In order to permit pumping to be effected up to the lowest possible limit, the impeller is preferably arranged to project beyond the entrance end of the shroud, and this projecting end portion of the impeller is preferably tapered so that its outer surface defines a cone surface having a tangential plane parallel to the tank bottom at a close distance from the latter. The entrance-end face of the shroud wall is preferably likewise tapered to form a continuation of this cone surface.

The accompanying part of a fuel tank in section and a transfer pump constructed and arranged in accordance with one embodiment of the invention.

Referring now to the drawing, the pump is mounted in a fuel tank 1, whose bottom is shown in vertical section. A pump housing 2, forming an impeller shroud in which an impeller 3 is rotatable abouta longitudinal axis 4, is supported on the tank bottom by a column 5 in such a manner that the inlet or entrance face 6 of the impeller and of the shroud is inclined at an angle a to the tank bottom, the same angle a being enclosed between the impeller axis 4 and the normal direction of drawing is an elevation showing gravity. in the illustrated embodiment the pump housing 2 is further provided with a lateral outlet stud 7 for the liquid delivered, and at its end remote from the inlet end 66 the housing contains an electric motor schematically indicated at 8, the electric supply wires to which may pass through the colum 5. As can bev seen in the drawing, the lower end of the impeller 3 projects beyond the lower end face of the shroud portion of the housing 2 and is tapered to provide a cone portion 9 with a cone angle of 2 (1r a) so that it has a tangential surface parallel to the bottom of the tank 1, thus com bining maximum freedom of liquid access of liquid from the tank to the impeller inlet with a close approach of the impeller to the tank bottom over a relatively large area. The inclination of the end surface 6 relative to the tank bottom also offers the advantage that any air or vapour which is liable to enter the pump with the fuel as the fuel level goes down, will be automatically returned to the tank at the side of the inlet face 6 remote from the point of its closest approach to the tank bottom. The inlet end face 10 of the impeller shroud is arranged to form a continuation of the surface of cone portion 9 of the impeller 3.

It will be evident to those skilled in the art that various details of the embodiment described may be moditied without departing from the scope of the invention. Thus the outlet of the liquid delivered by the pump could be arranged axially, or a radial impeller portion might be arranged at the outlet end of the axial impeller, thus facilitating, generally with the assistance of a volute outlet, the supply of liquid at a higher outlet pressure.

What we claim is:

l. A liquid axial flow fuel transfer pump for installation in a fuel tank having a flat bottom wall portion, said pump comprising a. a tubular casing having a longitudinal axis and an inlet face normal to said longitudinal axis and an annular wall adjacent said inlet diverging from said axis;

b. an axial flow impeller mounted for axial rotation in said tubular casing and along said longitudinal axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use of said fuel supply unit, the fuel engages said upstream end of said impeller and is forced into said tubular casing through said inlet face; and

. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face making an acute angle with a plane of said bottom wall portion and said annular wall is in close proximity to said bottom wall portion.

2. A transfer pump as'cla'imed in claim 1 in which said upstream end of said axial flow impeller projects upstream beyond said inlet face.

3. A liquid axial flow fuel transfer pump for installation in a fuel tank having a flat bottom wall portion, said pump comprising a tubular casing element, said casing element having a first inlet end portion constituted by an outward diverging frustro-conical surface and said casing terminating in a downstream substantially cylindrical portion, an axial flow impeller in said tubular casing element and mounted on the axis of said cylindrical portion, said axial flow impeller having an upstream end portion conforming to the shape of the outwardly diverging frustro-conical surface of said inlet end portion and projecting upstream out of said inlet whereby the pump liquid engages said upstream end of said impeller and is forced into the frustro-conical diverging end portion of said casing element, and a supporting means for rigidly attaching said tubular casing element at an acute angle to said flat bottom wall portion, whereby said projecting upstream end portion of said impeller and diverging end of said casing element lie in close proximity to and parallel to said flat bottom wall portion.

4. A transfer pump as claimed in claim 3 in which said outward diverging frustro-conical surface is followed by a downstream converging conical surface.

5. A fuel supply unit which comprises, in combination:

A. a fuel tank having a substantially flat bottom wall portion;

B. a liquid axial-flow fuel-transfer pump comprising 1. a tubular casing having a longitudinal axis and an inlet face normal to said longitudinal axis and an adjacent surface to said inlet diverging from said axis;

2. an axialflow impeller mounted for axial rotation in said tubular casing and along said longitudinal axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use of said fuel supply unit, the fuel engages said upstream end of said impeller and is forced into said tubular casing through said inlet face; and

C. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face making an acute angle with said bottom wall portion and said adjacent surface in a plane in close proximity to said bottom wall portion.

6. A fuel supply unit as claimed in claim 5 in which said upstream end of said axial flow impeller projects upstream beyond said inlet face.

7. A fuel supply unit as claimed in claim 5 in which said longitudinal axis of said tubular casing forms an angle of approximately 60 with said bottom wall portion.

8. A fuel supply unit which comprises, in combination: a fuel tank having a substantially flat bottom wall portion, and a liquid axial flow fuel transfer pump for installation in a fuel tank having a flat bottom wall portion, said pump comprising a tubular casing element, said casing element having a first inlet end portion constituted by an outward diverging frustro-conical surface and said casing terminating in a downstream substantially cylindrical portion, an axial flow impeller in said tubular casing element and mounted on the axis of said cylindrical portion, said axial flow impeller having an upstream end portion conforming to the shape of the outwardly diverging frustro-conical surface of said inlet end portion and projecting upstream out of said inlet whereby the pump liquid engages said upstream end of said impeller and is forced into the frustro-conical diverging end portion of said casing element, and a supporting means for rigidly attaching said tubular casing element at an acute angle to said flat bottom wall portion, whereby said projecting upstream end portion of said impeller and diverging end of said casing element lie in close proximity to and parallel to said flat bottom wall portion.

9. A liquid axial flow fuel transfer pump for installation in a fuel tank having a flat bottom wall portion, said pump comprising a. a tubular casing having a longitudinal axis and an inlet face normal to said longitudinal axis, said tubular casing being constituted by a diverging frustro-conical portion followed by a downstream converging frustro-conical portion, and terminating in a downstream substantially cylindrical portion; b. an axial flow impeller mounted for axial rotation in said tubular casing and along saidlongitudinal' axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use'of said fuel supply unit, the fuel engages said-upstream end of said impeller and is forced into said tubular casing through said inlet face; and

c. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face having the diverging frustoconical wall portion making an acute angle with a plane in close proximity to said bottom wall portion.

10. A transfer pump as claimed in claim 9 in which said up-stream end of said axial flow impeller conforms to the shape of said diverging frustro-conical portion and projects upstream beyond said inlet face.

11. A fuel supply unit which comprises, in combination:

A. a fuel tank having a substantially flat bottom wall portion; 1

B. a liquid axial-flow fuel-transfer pump comprising 1. a tubular casing having a longitudinal axis and an inlet face normal to said longitudinal axis, said tubular casing being constituted by a diverging frustro-conical portion followed by a downstream converging frustro-conical portion, and terminating in a downstream substantially cylindrical portion.

2. an axial flow impeller mounted for axial rotation in said tubular casing and along said longitudinal axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use of said fuel supply unit, the fuel engages said upstream end of said impeller and is forced into said tubular casing through said inlet face; and

C. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face having the diverging frustoconical portion making an acute angle with a plane in close proximity to and parallel to said bottom wall portion.

12. A fuel supply unit as claimed in claim 1 l in which said upstream end of said axial flow impeller conforms to the shape of said diverging frustro-conical portion and projects upstream beyond said inlet face.

l i i I!

Claims

1. A liquid axial flow fuel transfer pump for installation in a fuel tank having a flat bottom wall portion, said pump comprising a. a tubular casing having a longitudinal axis and an inlet face normal to said longitudinal axis and an annular wall adjacent said inlet diverging from said axis; b. an axial flow impeller mounted for axial rotation in said tubular casing and along said longitudinal axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use of said fuel supply unit, the fuel engages said upstream end of said impeller and is forced into said tubular casing through said inlet face; and c. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face making an acute angle with a plane of said bottom wall portion and said annular wall is in close proximity to said bottom wall portion.

2. A transfer pump as claimed in claim 1 in which said upstream end of said axial flow impeller projects upstream beyond said inlet face.

2. an axial flow impeller mounted for axial rotation in said tubular casing and along said longitudinal axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use of said fuel supply unit, the fuel engages said upstream end of said impeller and is forced into said tubular casing through said inlet face; and C. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face making an acute angle with said bottom wall portion and said adjacent surface in a plane in close proximity to said bottom wall portion.

2. an axial flow impeller mounted for axial rotation in said tubular casing and along said longitudinal axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use of said fuel supply unit, the fuel engages said upstream end of said impeller and is forced into said tubular casing through said inlet face; and C. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face having the diverging frusto-conical portion making an acute angle with a plane in close proximity to and parallel to said bottom wall portion.

5. A fuel supply unit which comprises, in combination: A. a fuel tank having a substantially flat bottom wall portion; B. a liquid axial-flow fuel-transfer pump comprising

7. A fuel supply unit as claimed in claim 5 in which said longitudinal axis of said tubular casing forms an angle of approximately 60* with said bottom wall portion.

9. A liquid axial flow fuel transfer pump for installation in a fuel tank having a flat bottom wall portion, said pump comprising a. a tubular casing having a longitudinal axis and an inlet face normal to said longitudinal axis, said tubular casing being constituted by a diverging frustro-conical portion followed by a downstream converging frustro-conical portion, and terminating in a downstream substantially cylindrical portion; b. an axial flow impeller mounted for axial rotation in said tubular casing and along said longitudinal axis, said axial flow impeller having an upstream end portion which extends at least substantially to said inlet face and which is such that, during use of said fuel supply unit, the fuel engages said upstream end of said impeller and is forced into said tubular casing through said iNlet face; and c. supporting means for rigidly attaching said tubular casing at an acute angle to said bottom wall portion with said inlet face having the diverging frusto-conical wall portion making an acute angle with a plane in close proximity to said bottom wall portion.

11. A fuel supply unit which comprises, in combination: A. a fuel tank having a substantially flat bottom wall portion; B. a liquid axial-flow fuel-transfer pump comprising

12. A fuel supply unit as claimed in claim 11 in which said upstream end of said axial flow impeller conforms to the shape of said diverging frustro-conical portion and projects upstream beyond said inlet face.