GB2290848A

GB2290848A - Multi channel pipes

Info

Publication number: GB2290848A
Application number: GB9413330A
Authority: GB
Inventors: Gilles Ausias
Original assignee: Draftex Industries Ltd
Current assignee: Laird Holdings Ltd
Priority date: 1994-07-01
Filing date: 1994-07-01
Publication date: 1996-01-10
Also published as: GB9413330D0

Abstract

A pipe for fluid transport, such as for conveying fuel in a motor vehicle from its fuel tank to its engine and in the opposite direction, comprises an outer wall (10) concentric with an inner tube (6) which is supported from the inside of the outer wall (10) by radially directed webs (12). A second tube (8) is thus provided which is concentric with but isolated from the inner tube (6). The inner and outer tubes (6, 8) enable separate flows of fluid, possibly in opposite directions, to be achieved by means of a single pipe. <IMAGE>

Description

PIPES The invention relates to pipes. Pipes embodying the invention may, for example, be used for transporting fluids in motor vehicles. However, many other applications are possible.

According to the invention, there is provided a pipe, comprising a plurality of substantially parallel side-by-side longitudinally extending tube means enclosed within a common outer wall.

According to the invention, there is also provided a pipe comprising an outer tubular wall, a first tube means inside the outer wall and axially parallel therewith and with its wall spaced throughout its peripheral surface from the outer wall by at least one radially directed web which extends longitudinally within the pipe, a second tube means being defined between the wall of the first tube means and the outer wall.

According to the invention, there is further provided a pipe of circular cross-section, comprising a central tube extending along the length of the pipe and concentric with its axis, an outer wall of the pipe which is arranged concentrically around and spaced from the central tube and extends along the length of the pipe so as to define a space inside the outer wall and outside the central tube and which extends along the length of the pipe, and support means supporting the central tube from the outer wall.

Pipes embodying the invention for transporting fluids in motor vehicles will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which: Figure 1 is a cross-section through one of the pipes; Figure 2 is a cross-section through another of the pipes; Figure 3 is a cross-section through a further one of the pipes; and Figure 4 is a cross-section through a connecting piece for making a connection to one of the pipes.

As shown in Figure 1, the pipe 5 comprises two concentric tubes 6 and 8. The tube 6 has a wall 7 which is supported from the inside of the exterior wall 10 of the pipe 5 by means of radially directed webs 12, there being four such webs in this example though more or less than this number may be provided.

The webs 12 may each extend longitudinally for the full length of the pipe 5. In this case, the outer tube 8 consists in effect of four mutually isolated arcuately-shaped tube parts 8A,8B,8C and 8D. Instead, though, the webs 12 need not extend continuously along the full length of the pipe 5 but may be arranged interruptedly along the length of the pipe and/or provided with through holes at intervals along the length of the pipe; in this way, the tube parts 8A,8B,8C and 8D are connected to each other.

The pipe 5 may be produced in any suitable material or combination of materials. For example, it can be made of plastics material or elastomeric material, such as a thermoplastic material, a thermoplastic elastomer or an elastomer, and different combinations of these materials may be used. The pipe may be manufactured by an extrusion process or, where different materials are used, by a co-extrusion process.

Alternatively, the pipe may be made from metal such as a metal alloy.

The pipe 5 of Figure 1 may be used in any suitable application where it is required to transport fluids in two separate streams between two points, with one fluid stream flowing in the tube 6 and the other in the tube 8.

The fluids may of course be travelling in the same or in opposite directions and may be liquid or gaseous.

The pipe 5 shown in Figure 1 may be used advantageously in a motor vehicle for transporting the fuel between the fuel tank and the engine. Thus, in cases where fuel has to pass in both directions between the fuel tank and the engine, one flow of the fuel can take place in the tube 6 and the other in the tube 8. The surplus fuel returning from the engine to the fuel tank may be warm, and the arrangement of the two concentric tubes 6 and 8 is thus advantageous because the returning warm fuel pre-warms the fuel travelling to the engine and, in carrying out this warming process, becomes cooled before it reaches the fuel tank.

Another possible application of such a pipe is in the cooling system of a motor vehicle.

The pipe 5 is advantageous because, as compared with two separate pipes, it can be mounted in position in a single operation. Furthermore, in cases where pipes need to be provided with exterior coverings or coatings for various protective or environmental reasons, such a covering or coating operation only has to be carried out once. For example, fuel pipes in motor vehicles are required to minimise or eliminate escape of fuel or fuel vapour through the pipe wall - for safety and environmental reasons. Special impervious coatings or coverings may therefore need to be placed around the outside wall 10 of the pipe. The pipe 5 of Figure 1 is thus advantageous because this operation only has to be carried out once.

Such protective covering may also be required for fire-protection purposes or to protect against damage, particularly in the case where the pipe runs under the vehicle and may be struck by debris thrown up from the road.

In the case where the webs 12 are continuous along the length of the pipe, the pipe can be used to transport more than two separate streams of fluid. Thus, one or more of the tube parts 8A,8B,8C and 8D can be used to transport a fluid flow which is different and separate from the fluid flow in the others or other of them (in the same or in different directions), while the tube 6 transports a further fluid flow.

Figure 2 shows a modified form of the pipe 5 of Figure 1 and parts in Figure 2 corresponding to those in Figure 1 are correspondingly referenced.

As shown in Figure 2, the pipe 5 comprises an inner tube 6 and an outer, concentric, tube 8. In this case, the inner tube 6 is supported by only two webs 12. Again, each of these webs can extend uninterruptedly along the full length of the pipe so as effectively to divide the tube 8 into arcuate tube parts 8A and 8B. Instead, however, the webs 12 can be interrupted along the length of the pipe so that the tube parts 8A and 8B are connected. As an alternative, the webs 12 can be provided with through holes at intervals along the length of the pipe for the same purpose.

In addition, the pipe 5 of Figure 2 has an exterior surrounding covering 14. The interior tube 6, the webs 12 and the wall 10 of the exterior tube 8 may be made of polyamide which has very good impermeability. The exterior covering layer 14 may be produced by extrusion or moulding from vulcanised rubber to provide a good resistance to heat, fire and mechanical damage.

The pipe of Figure 2 can be used for similar applications to those of the pipe of Figure 1.

Again, the two tube parts 8A and 8B can be used to transport different and completely separate fluid flows (in the same or different directions) if the webs 12 are continuous along the length of the pipe, the tube 6 carrying a further flow. The pipe can thus be particularly advantageous for use in motor vehicles where three fluid flows have to take place between the fuel tank and the engine. For example, in certain cases, such fluid flows can comprise (a) fuel flowing from the fuel tank to the engine, (b) surplus fuel flowing from the engine back to the fuel tank, and (c) fuel vapour flowing from the fuel tank to a vapour tank near the engine. For example, tube 6 can be used for the fuel flowing from the fuel tank to the engine, tube part 8A can be used for transporting the surplus fuel flowing back to the fuel tank, and tube part 8B can be used for the vapour.

Figure 3 shows a further modified form of the pipe 5 and, again, items in Figure 3 corresponding to those in Figure 2 are correspondingly referenced. In this case, though, the pipe comprises three concentric tubes instead of the two concentric tubes of Figures 1 and 2. Thus, there is the interior tube 6, the exterior tube 8, and an intermediate tube 16. Webs 12 (four in this example) support the wall of the interior tube 6 from the exterior wall 10 of the pipe. In addition, the webs 12 support an integral concentric intermediate wall 18 which separates the exterior tube 8 from the intermediate tube 16.

The webs 12 can again each extend uninterruptedly along the length of the pipe 5 so that the exterior tube 8 comprises, in effect, four separated tube parts 8A,8B,8C and 8D. Similarly, the intermediate tube 16 comprises four separate tube parts 16A,16B,16C and 16D. Instead, though, the web 12 can be constructed so that the four tube parts of each of the exterior and intermediate tubes 8 and 16 are connected to each other (though the tube 8 and the tube 16 will not be connected to each other).

The pipe 5 of Figure 3 can be used where three fluid flows have to take place. It is particularly suitable for the example described above with reference to Figure 2, where such fluid flows comprise (a) fuel flowing from the fuel tank to the engine of a motor vehicle, (b) surplus fuel flowing in the opposite direction, and (c) fuel vapour flowing from the fuel tank to the vapour tank. Thus, the interior or central tube 6 can transport the fuel from the fuel tank to the engine, the fuel returning to the fuel tank can flow in the intermediate tube 16, and the fuel vapour can flow in the exterior tube 8. The returning fuel in the intermediate tube 16 pre-warms the fuel flowing to the engine in the tube 6.The exterior tube 8, conveying the fuel vapour, provides a significant reduction in the overall permeability of the pipe and increases the thermal insulation and protection against fire.

Again, the pipe of Figure 3 can be produced in a variety of different materials such as those mentioned above.

Figure 4 shows a connecting piece 20 for making connection to a pipe 5 of the type shown in Figure 1. The connecting piece 20 is used to connect the interior tube 6 of the pipe 5 to a single pipe 22, and to connect the exterior tube 8 of the pipe 5 to a single tube 24.

The connecting piece 20 comprises a central stub pipe 26 which is inserted within the tube 22 and clamped therein by an exterior clamp 28 of any suitable type. Its opposite end 30 is sized to be a tight sealing fit within the end of the tube 6.

In addition, the connecting piece 20 has an outer, concentric, chamber 32 which is a tight sealing fit within the exterior wall 10 of the pipe 5 and thus connects with the exterior tube 8. A stub pipe 34 leads from the concentric chamber 32 into the end of the tube 24 and is tightly clamped in position by an exterior clamp 36 of any suitable type.

A similar connecting piece may be used for connecting to the pipe 5 of Figure 2. A modified form of the connecting piece 20 may be used for connecting to the three concentric tubes of the pipe 5 of Figure 3.

The pipes described and illustrated may be used in many other applications outside motor vehicles.

Claims

1. A pipe, comprising a plurality of substantially parallel side-by-side longitudinally extending tube means enclosed within a common outer wall.

2. A pipe according to claim 1, in which a first one of the tube means is concentric with the longitudinal axis of the pipe and the next or second tube means is arranged with its cross-section extending at least partially around the cross-section of the first tube means.

3. A pipe according to claim 2, in which the first tube means is supported by means of at least one web extending in a radial direction from the first tube means towards the outer wall.

4. A pipe according to claim 3, in which there are a plurality of the webs which extend across the space within the second tube means.

5. A pipe comprising an outer tubular wall, a first tube means inside the outer wall and axially parallel therewith and with its wall spaced throughout its peripheral surface from the outer wall by at least one radially directed web which extends longitudinally within the pipe, a second tube means being defined between the wall of the first tube means and the outer wall.

6. A pipe according to claim 5, including a further tubular wall positioned between the outer wall and the wall of the first tube means so that a third tube means is provided between the outer wall and the said further wall and the second tube means is provided between the further wall and the wall of the first tube means.

7. A pipe according to claim 6, in which the further wall is spaced from the outer wall by at least one radially directed web which extends longitudinally within the pipe.

8. A pipe according to any one of claims 3 to 7, in which the or each web extends uninterruptedly along the length of the pipe.

9. A pipe according to any one of claims 3 to 7, in which the web, or at least one of the webs, is arranged to provide a through passage extending from one side of the web to the other side.

10. A pipe according to any preceding claim, including a separate protective covering on the outside of the outer wall.

11. A pipe according to any preceding claim, made of flexible material.

12. A pipe according to claim 11, in which the flexible material is a thermoplastic material, a thermoplastic elastomer, or an elastomer.

13. A pipe according to any one of claims 1 to 10, made at least partially of metal.

14. A pipe according to any preceding claim, including a connecting pipe adapted to make sealing connection with an end of the pipe and including connecting means making separate connections with each of the plurality of tube means, for enabling separate exterior connections with each of those tube means.

15. A pipe of circular cross-section, comprising a central tube extending along the length of the pipe and concentric with its axis, an outer wall of the pipe which is arranged concentrically around and spaced from the central tube and extends along the length of the pipe so as to define a space inside the outer wall and outside the central tube and which extends along the length of the pipe, and support means supporting the central tube from the outer wall.

16. A pipe according to claim 15, in which the support means comprises at least one web extending radially from the central tube to the inside of the outer wall and extending across the said space.

17. A pipe according to claim 16, in which there are a plurality of the webs spaced apart angularly around the axis of the pipe.

18. A pipe according to any one of claims 15 to 17, in which the or each web is arranged to divide the said space into a plurality of mutually isolated sub-spaces each extending along the length of the pipe.

19. A pipe according to any one of claims 15 to 18, including a further wall extending concentrically with and between the outer wall and the outside of the first tube and dividing the said space into radially separated and mutually isolated spaces.

20. A pipe according to any one of claims 15 to 21, including a separate protective covering on the outside of the outer wall.

21. A pipe according to any one of claims 15 to 20, made of flexible material.

22. A pipe according to claim 21, in which the flexible material is a thermoplastic material, a thermoplastic elastomer, or an elastomer.

23. A pipe according to any one of claims 15 to 20, made at least partially of metal.

24. A pipe according to any one of claims 15 to 23, including a connecting piece adapted to make sealing connection with an end of the pipe and including connecting means making separate connections with the first tube end and the or each space.

25. A pipe for fluid transport, substantially as described with reference to Figure 1 of the accompanying drawings.

26. A pipe for fluid transport, substantially as described with reference to Figure 2 of the accompanying drawings.

27. A pipe for fluid transport, substantially as described with reference to Figure 3 of the accompanying drawings.

28. A pipe and connecting piece for fluid transport, substantially as described with reference to Figure 4 of the accompanying drawings.