GB2276924A

GB2276924A - Combined flange and seal

Info

Publication number: GB2276924A
Application number: GB9404307A
Authority: GB
Inventors: Barry C Risbridger
Original assignee: W&J Risbridger Ltd
Current assignee: W&J Risbridger Ltd
Priority date: 1993-03-05
Filing date: 1994-03-04
Publication date: 1994-10-12
Anticipated expiration: 2014-03-04
Also published as: GB9404307D0; GB9304547D0; GB2276924B

Abstract

The invention relates to a method of forming a seal between a fuel pump suction pipe (1) and a membrane (2) extending across the base of a fuel pump housing, which comprises attaching a gaiter seal (5) to the suction pipe (1) at a point above the membrane (2) so that the skirt (7) of the gaiter depends downwardly to contact the membrane and forming the membrane with an upstand (8) in the region where the suction pipe passes therethrough. <IMAGE>

Description

COMBINED FLANGE AND SEAL This invention relates to the installation and connection of fuel pumps to suction lines from underground storage tanks.

Regulations recently brought into force in the U.K., which cover the installation of petrol pumps, require the installation of a leak-proof plate or membrane across the entire area at the base of the pump. The regulations further provide that any pipes passing through the plate or membrane should not permit a leakage path for fuel.

However, in order to connect the pump to the suction line, it is necessary to penetrate this member and to effect a seal between the pipe and the membrane.

Normal practice is to fit a triangular screwed flange to the suction pipe above the membrane, and to attempt to seal the gap between the flange and the membrane with a gap filling sealant. However, in practice it is extremely difficult to effect a satisfactory seal and there is no method available for checking the integrity of such a seal.

According to the present invention there is provided a method of sealing a fuel pump suction pipe in a membrane extending across the base of the fuel pump housing, which comprises attaching a gaiter seal to the suction pipe above the point at which it extends through the membrane so that the gaiter skirt depends downwardly to the membrane and forming the membrane with an upstand in the region where the suction pipe passes therethrough, thereby forming a labyrinth seal between the membrane and the gaiter skirt.

One further advantage of the construction in accordance with the invention is that the screwed joint between the pipe and the flange can be easily pressure tested for leakage before the gaiter is stretched into a final position in a machined groove (which may be, e.g. of square or circular section, thus forming a reliable seal with the flange.

The invention is illustrated in the accompanying drawings, in which: Figure 1 shows a typical installation in accordance with the prior art in which a petrol pipe suction pipe 1 extends through a fuel impervious membrane 2 in the base of a petrol dispensing pump 3, Figure 2 shows a section through an arrangement in accordance with the invention in which a suction pipe 1 extends through a leak-proof plate or membrane 2 and is fitted with a labyrinth seal in accordance with the invention, Figure 3 is a plan view of the labyrinth seal arrangement of the present invention, Figure 4 is a section similar to Figure 3 of a modification of the arrangement shown in Figure 3, in which the suction pipe is fitted with an extension, and Figure 5 is a plan view of the coupling and seal shown in Figure 4.

Referring to the drawings (and in particular Figures 2 and 3), a conventional petrol pump is modified in accordance with the invention by providing a circular upstand 8 to a leak-proof plate or membrane 2 in the base of the petrol pump housing. A suction pipe 1 extends through the leak-proof plate 2 and a flange 4 is clamped to the pipe 1 at a position spaced above the plate.

Conveniently, an underpump valve, e.g. as described in our UK patent application No. 9306893 (Publication No.

2265988), may be bolted to the flange. A flexible gaiter 5 manufactured from a petroleum resistant plastics or rubber material has an upper ribbed neck portion 6 which is received in a circular groove 12 machined in the flange 4. The gaiter 5 has a depending skirt 7 which touches the membrane 2 to provide a labyrinth seal therewith, and with the upstand 8. As can be seen in Figure 3, the flange 4 has a generally cylindrical lower part 9 with an upper part 10 shaped as a generally triangular projection.

Bores 11 are drilled in the face of the part 10 for attachment of a mating face of an underpump valve.

In Figures 4 and 5, the arrangement of the coupling and seal is similar to that shown in Figures 1 to 3, and the same reference numerals are used to indicate equivalent parts. The main difference is that in Figure 4, the flange is attached to an extension pipe 20 which is fixed into the central opening 21 in the flange, e.g. by threads. Extension pipe 20 is received within suction pipe 1 and a liquid-tight seal is provided by a nut 22, which is screwed onto the upper end of pipe 1. An '0' ring 23 provides a seal between the outer surface of the extension pipe and the interior of the suction pipe.

Claims

CLAIMS:

1. A method of forming a seal between a fuel pump suction pipe and a membrane extending across the base of a fuel pump housing, which comprises attaching a gaiter seal to the suction pipe at a point above the membrane so that the skirt of the gaiter depends downwardly to contact the membrane and forming the membrane with an upstand in the region where the suction pipe passes therethrough.

2. A method according to claim 1 wherein the gaiter is connected to a flange which is secured to the suction pipe and the gaiter depends downwardly into contact with the membrane.

3. A method according to claim 1 or 2 wherein the gaiter is connected to an extension pipe which is sealingly connected to the suction pipe.

4. A method according to claim 3 wherein the extension pipe is received in a collar secured to the upper end of the suction pipe.

5. A pipe coupling and seal for a fuel pump which comprises a flange adapted to be secured to a fuel suction pipe or an extension thereof and a gaiter connected to the flange and having a downwardly depending skirt adapted to contact and seal against a surface surrounding the suction pipe.

6. A coupling and seal as claimed in claim 5 wherein the gaiter is retained in a groove extending around the flange and has a skirt having a concertina-like shape.