GB2475485A

GB2475485A - A pipe extending in two different planes

Info

Publication number: GB2475485A
Application number: GB0920182A
Authority: GB
Inventors: John Stobbart
Original assignee: Vector International Ltd
Current assignee: Freudenberg Oil and Gas Technologies Ltd
Priority date: 2009-11-18
Filing date: 2009-11-18
Publication date: 2011-05-25
Anticipated expiration: 2029-11-18
Also published as: GB2475485B; GB0920182D0

Abstract

A conduit pipe comprising a first end and a second end extends out of a first plane into a second plane. The ends of the pipe are configured so as to be able to connect a pressurised vessel to a manifold (both not shown), and may comprise hubs 11, 17. Ideally the pipe is a continuous unitary pipe having no joints, although bends made of different / stronger materials that the straight sections are envisaged. When connected, gradient of the pipe is downwards in general, with the possibility of horizontal sections. The ends of the pipe may be offset. The pipe may bend 13, 14, 15 several times with the pipe angles totalling between 270 - 360 degrees. The serpentine piping / tubing may be utilised in the storage and transport of compressed gas (e.g., in a gas-carrier ship), where it is able to withstand vibrations arising from transportation / fluid flow by virtue of its more flexible shape.

Description

Conduit Pipe The present invention relates to a conduit pipe for enabling transfer of a fluid between a vessel, preferably a pressure vessel, and a manifold conduit.

Vessels for storage and transport of a material such as, for example, compressed gas are provided in the art however it is a requirement that the material within the vessel may be transfeffed to and from the vessel as required. For this purpose, an outlet is provided in the vessel to which is connected a conduit pipe which may enable transfer of the liquid in the vessel to a desired location. It is often a requirement that a number of vessels are provided in order to enable transport or storage of the material in a safe manner as the provision of smaller vessels capable of storing less material may be managed if a fault arises. It is therefore required that a manifold conduit is provided into which the conduit pipes leading from the outlet/inlet of the vessel are linked in fluid communication. Such a system may therefore be arranged comprising a plurality of vessels which may be under pressure that are linked in fluid communication to a manifold conduit via a plurality of conduit pipes. Such a system may be utilised for storing and/or transporting compressed gas.

It is known that in some environments, in particular relating to the storage and transport of pressurised gas that some flexibility in the conduit pipes is required in order that vibration associated with the vehicle carrying the vessels or alternatively the location in which the vessels are sited does not lead to leakage associated with the conduit pipes.

Furthermore, construction tolerances associated with the opening of the manifold conduit to the opening of the pressure vessel will never be exact. Accordingly, it is necessary that there is some flexibility in the conduit pipe.

The point at which is most at risk of fatigue cracking is the connection point of the conduit pipe to the manifold conduit or the vessel, or more specifically the point at which the conduit pipe connects to a hub which in turn connects to a vessel or manifold conduit.

In standard fatigue analysis, vibration for example may lead to fatigue cracking. For this reason, it is known that a generally U-shaped conduit pipe as shown in Figure 1 allows

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some flexibility between each end of the conduit pipe. It is known that in the direction Y the flexibility is approximately proportional to the sum of lengths L1 and L2 of the sections and the width W where they are joined by a joining section, flexibility in the direction Z is approximately proportional to the sum of L1 and L2,while flexibility in the direction X is approximately proportional only to W. The curved form shown for the joining section contributes to the effective lengths of the horizontal sections that has no significant effect on the width W. The present invention provides a significantly improved affangement.

According to a first aspect of the present invention, there is a conduit pipe having a first end and a second end, one of the first and second end configured to be secured to a pressurised vessel and the other of the first and second end being configured to be secured to a manifold conduit, the conduit pipe defining an outward and return flow path between the vessel and the manifold conduit, wherein the conduit pipe extends out of a first plane into a second plane.

A significant benefit associated with the present invention is that flexibility may be achieved in X, Y and Z directions through the reduction in stress and balancing of stresses in the conduit pipe.

The conduit pipe is beneficially a continuous pipe having no joints between the first and second ends, and even more beneficially comprises a metal. The advantage of such a material is there are no discontinuities in the pipe which may lead to failure and additionally the pipe can be bent using known bending techniques to provide the desired shape.

The conduit pipe, in at least one orientation, preferably has a gradient that is substantially downhill between the first and second end. This includes the scenario where at least a portion of the pipe is horizontal in use. It is beneficial that no uphill sections are provided as such a configuration ensures that no liquid sits in the conduit pipe. The liquid either passes through the conduit pipe into the vessel or from the vessel into the manifold conduit.

The conduit pipe preferably defines a flow path successively between the first end through a second point and a third point and the second end, wherein the first plane is defined between the first end, the second end and the second point, and the second plane is defined between the first end, the second end and the third point, wherein an intermediate point is provided intermediate the second and third point, the intermediate point located in neither of the first or second planes. Preferably, the shortest distance from the intermediate point to a line drawn between the first and second end is at least 25% of the straight line distance between the first and second end of the conduit pipe.

Such a distance is beneficial to ensure that the desiid flexibility of the conduit pipe is achieved. Even more beneficially, the shortest distance from the intermediate point to a line drawn between the first and second end is at least 50% of the straight line distance between the first and second end of the conduit pipe.

The portion between the first end and the second point preferably includes a first elbow portion. Elbow portions are beneficially provided for ease of manufacturing. Straight portions of pipe followed by bends are easier to manufacture than a continuously bent pipe.

The portion between the second end and the third end beneficially includes a second elbow portion.

The intermediate point is beneficially located in an intermediate portion, wherein the intermediate portion joins the first and second elbow portion. This intermediate portion is beneficially substantially vertical when the conduit pipe is in use. Even more beneficially, the intermediate portion is substantially linear.

The first and second ends are beneficially substantially parallel. Preferably a portion of the conduit pipe extends from each of the first and second ends and are substantially parallel.

The first and second ends are preferably offset such that the first and second ends sit in different planes, the planes being drawn substantially perpendicular to the flow direction at the first and second ends. Such a configuration improves flexibility of the conduit pipe.

The hub portion is configured to provide a seal between the conduit pipe and the vessel and the conduit pipe and the manifold conduit. It will be appreciated, however, that hub portions at each end of the conduit pipe may be the same or different.

The conduit pipe beneficially turns through at least 270° between the first and second end of the conduit pipe. Such a configuration enables closer packing of the vessels and manifold conduit. Even more beneficially, the conduit pipe turns substantially 360° between the first and second end of the conduit pipe. Accordingly, the conduit pipe extends outwardly away from the vessel or manifold conduit and in effect turns back on itself to the vessel or manifold conduit.

The present affangement is particularly advantageous as the point in the conduit pipe at which the stress is at a maximum will lead to fatigue increasing at such a point and as such leading to potential fatigue cracking at this point. By approximately balancing the stresses at a lower level, such effect is significantly reduced.

A benefit of such offsetting of the first and second ends is the balancing of stresses, whilst also providing for increased overall storage capability due to closer packing of the pressure vessels. In one embodiment it is envisaged that pressure vessels extend in at least two horizontal rows having a manifold conduit therebetween which connects to the vessel in each of the rows. Accordingly, offsetting of the first and second ends improves storage capability.

The present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic representation of a conduit pipe capable of connecting a manifold conduit to a vessel.

Figure 2 is a schematic representation of the side view of an exemplary embodiment of the present invention.

Figure 3 is a schematic plan view of the conduit pipe as indicated in Figure 4 according to the same exemplary embodiment of the present invention.

Figure 4 is a schematic end view of a conduit pipe as shown in Figures 4 and 5 according to an exemplary embodiment of the present invention.

Figure 5 is a schematic isometric view of the conduit pipe shown in Figures 2-4 according to an exemplary embodiment of the present invention.

Figure 6 is a schematic isometric view of a conduit pipe according to an alternative exemplary embodiment of the present invention without showing hubs mounted at the ends of the pipe.

Refeffing to Figures 2-5, it is beneficial to view the drawings together to understand the configuration of the conduit pipe according to an exemplary embodiment of the present invention.

Refeffing to figures 2-5, the conduit pipe extends between a hub 11 for connection to a manifold conduit or vessel and a hub 17 also for connection to a manifold conduit or vessel. In a subsequent description reference has been made to hub 11 being connected to the manifold conduit and hub 17 being connected to the vessel, however, this may easily be reversed. The hubs are welded to the conduit pipe and the hubs are configured to be secured to the manifold conduit or vessel, preferably by welding. The hubs are generally provided in opposing portions which are drawn together to provide a joint. The hubs may extend substantially parallel to each other. This enables improved ease of assembly. For ease of manufacture and to allow smooth flow theithrough the conduit pipe comprises a number of straight portions joined by bends 12, 13, 14, 15 and 16 which beneficially comprise an equal radius. As most clearly seen from the end view shown in Figure 4, the flow path is generally downhill between the hub 11 and hub 17. According to an exemplary embodiment of the present invention the conduit pipe comprises a first elbow portion and a second elbow portion. These elbow portions may be considered, for example, as defined between points 11, 12 and 13, and a second elbow portion which may be considered to be defined between, for example, 14, 15 and 16. It is beneficial that the conduit pipe is made of a single elongate pipe which is bent into the configuration required, however, it will be appreciated that the bent portion for the elbow, for example, may be made of an alternative material allowing flexibility, or may for example, be made having a concertina effect thereby enabling bending of the pipe. Due to the pressure in which the system is under in use however, the pipe is beneficially a single elongate metallic pipe which has been deformed to define the shape of the pipe.

In the embodiment shown, there is a first straight portion between the hub 11 and bend 12 and a further straight portion between the bend 12 and bend 13. Following the bend 13 the pipe drops substantially vertically downwardly into bend 14. A further elongate portion of pipe extends from bend 14 to bend 15, and a further elongate straight portion of pipe extends between bend 15 and bend 16. Following bend 16, a further straight portion extends to the hub 17.

A significant benefit of the present invention is that deflection of the conduit pipe is enabled in X, Y and Z directions as indicated in the figures. This is achieved through the shape of the pipe as defined in the claims of the present application. It is beneficial that the hub 11 and hub 17 are offset relative to each other in the Z direction. This improves flexibility in the Z direction. The length between bends 13 and 14 achieves flexibility in the X direction and flexibility in the Y direction is approximately proportional to the sum of the extension outwardly from a hub between hub 11 and bend 13 and bend 14 and hub 17. Offsetting of the hubs 11, 17 in the Z direction enables closer packing of the manifold conduit and plurality of vessels as it will be appreciated that vessels may be both above and below the manifold conduit meaning more openings are necessary in the manifold conduit for receipt of conduit pipes.

In order to achieve increase reduction in stresses and further balance the stresses in the pipe at the hubs 11, 17, it is beneficial to ensure that the distance between an intermediate point in the pipe which sits in neither plane defined by points 11, 12 and 17 or 11, 15 and 17 for example which is intermediate points 12 and 15 is positioned at a distance at least 25% of the straight line length between 11 and 17 drawn from the intermediate point and measured to the intersection substantially perpendicular to the straight line between 11 and 17.

Refeffing to Figure 6, an alternative exemplary embodiment of the present invention is shown without hubs 11 and 17. Instead, each of the pipes ha and 17a are shown. In this embodiment, the portions of pipe extending between ha and 12 and 17a and 15 are substantially parallel, meaning that in use these sections are substantially horizontal.

Furthermore, there is no additional bend between 17a and 15.

A significant advantage of the present invention is that stresses are substantially equalized at the hubs 11 and 17 of the conduit pipe which reduces significantly the chance of fatigue cracking at these points due to concentrated localised stresses. In use, this is particular important as the conduit pipe may be used in environments in which there are vibrations such as in a ship configured to cany a plurality of pressure vessels which may contain, for example, compressed gas. Vibrations are likely to occur from the ship's engine and also from the sea. Furthermore, the flexibility of the conduit pipe according to the present invention means that if the spacing in any of the X, Y or Z directions of the manifold conduit and pressure vessel openings are not exactly correct, there is some flexibility in the conduit pipe.

It will be appreciated that in use modifications may be made to the exact configuration of the conduit pipe and as indicated in the figures this is an exemplary embodiment only. In use, it is possible that vibration in the conduit pipe may occur due to resonant frequencies of the ship for example and as such modifications may be required to the exact configuration.

A frirther significant advantageous feature of the present invention is that a downhill flow path is provided all the way between hubs 17 and 11. This is particularly important as it means that no material for storing in the vessel such as compressed gas in liquid form will sit in the conduit pipe.

The present invention has been described by way of example only and it will be appreciated by a person skilled in the art that modifications and variations may be made without departing from the scope of protection afforded by the appended claims.

Claims

Claims 1. A conduit pipe having a first end and a second end, one of the first and second end configured to be secured to a pressurised vessel and the other of the first and second end being configured to be secured to a manifold conduit, the conduit pipe defining an outward and return flow path between the vessel and the manifold conduit, wherein the conduit pipe extends out of a first plane into a second plane.
2. A conduit pipe according to claim 1 wherein the conduit pipe is a continuous pipe, having no joints between the first and second end.
3. A conduit pipe according to any of claims 1-2 wherein the conduit pipe comprises a metal.
4. A conduit pipe according to any preceding claim wherein a substantially downward flow path is defined between the first and second ends.
5. A conduit pipe according to any preceding claim wherein the conduit pipe defines a flow path successively between the first end through a second point and a third point and the second end, wherein the first plane is defined between the first end, the second end and the second point, and the second plane is defined between the first end, the second end and the third point, wherein an intermediate point is provided in the flow path intermediate the second and third point, the intermediate point being located in neither of the first or second planes.
6. A conduit pipe according to claim 5 wherein the shortest distance from the intermediate point to a line drawn between the first and second end is at least 25% of the straight line distance between the first and second end of the conduit pipe.
7. A conduit pipe according to claim 5 wherein the shortest distance from the intermediate point to a line drawn between the first and second end is at least 50% of the straight line distance between the first and second end of the conduit pipe.
8. A conduit pipe according to claim 5 wherein the portion between the first end and the second point includes a first elbow portion.
9. A conduit pipe according to claim 5 wherein the portion between the second end and the third point includes a second elbow portion.
10. A conduit pipe according to claims 8 and 9 wherein the intermediate point is located in an intermediate portion, wherein the intermediate portion joins the first and second elbow portions.
11. A conduit portion according to claim 10 wherein the intermediate portion is substantially linear.
12. A conduit portion according to any preceding claim wherein the first and second ends are substantially parallel.
13. A conduit portion according to claim 12 wherein a portion of the conduit pipe extending from each of the first and second ends are substantially parallel.
14. A conduit portion according to any of claims 12-13 wherein the first and second ends are offset such that the first and second ends sit in different planes, the planes being drawn substantially perpendicular to the flow direction at the first and second ends.
15. A conduit pipe according to any preceding claim comprising a hub portion in connection with the conduit pipe at the first end and second end for communicating with the vessel and manifold conduit respectively.
16. A conduit pipe according to any preceding claim wherein the conduit pipe turns through at least 2700 between the first and second end of the conduit pipe.
17. A conduit pipe according to claim 16 wherein the conduit pipe turns through substantially 360° between the first and second end of the conduit pipe.
18. A conduit pipe as hereinbefore described with reference to the accompanying drawings.