GB2250079A

GB2250079A - A piggy back pipe line saddle

Info

Publication number: GB2250079A
Application number: GB9124748A
Authority: GB
Inventors: Michael Wyn Harold
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-11-21
Filing date: 1991-11-21
Publication date: 1992-05-27
Anticipated expiration: 2011-11-21
Also published as: GB9124748D0; GB9025292D0; GB2250079B

Abstract

A piggy back pipeline arrangement in which a saddle (4, 24) is interposed between two pipelines (2, 22) which are then clamped together: the saddle has a bushing means (12, 32). The bushing means is securable to the saddle and at least partly encircles a smaller (3, 23) of the two pipelines. After fitting the bushing means is closed round the smaller pipeline and when the pipelines are strapped together the arrangement relieves stress and helps to prevent the displacement of the strapping. <IMAGE>

Description

A PIGGY BACK PIPELINE The present invention relates to a pipeline saddle arrangement in which a saddle is interposed between two pipelines which are then clamped together. This is known as a piggy back pipeline. It is known to strap a small gas pipeline to a larger pipeline, the smaller pipeline being used for conveying methanol. Such an arrangement is shown in US Patent 4,678,147.

In similar saddles to those shown in the said US Patent, the saddles are slit below the smaller pipeline and are fitted around that pipeline before being seated on the larger pipeline. After seating the strap or strapping is then fitted and tightened around the saddle and larger pipeline to ensure that both pipelines are secured together.

A problem arises during laying the pipelines, since there is a tendency for one pipeline to move axially with respect to the other pipeline. Since the saddles are normally made of rubber or the like and are tightly strapped to the pipelines there can be no axial movement between the saddle and any of the pipelines so that the saddles then become stressed during the pipeline laying operation. This stress can damage the saddles and cause the strapping to be displaced on the saddles.

According to the present invention a piggy back pipeline~ saddle is provided with a large pipeline seating surface, a small pipeline seating, and a bushing means securable to the saddle and which can be closed along its axial length to at least partly encircle the smaller pipeline.

In one embodiment of the invention the bushing means is preferably made from a plastics material and provides an intervening member between the saddle and smaller pipeline so that the smaller pipeline is enabled to move axially relative to the saddle and larger pipeline. The bushing means is preferably mounted securably to the saddle by means of a small pipeline enicrcling hole in the saddle which is slit along a length of the encircling hole from the hole to the exterior of the saddle, the bushing means being fittable within the hole.

Preferably the bushing means is formed as two halves, although a single bushing means with only one longitudinal slit can be provided.

The bushing means may have flanges on each end extending when in position on the smaller pipeline substantially perpendicularly away from the exterior surface of the smaller pipeline. These flanges are suitably provided at each end of the bushing means and help to retain the bushing means in the saddle.

In a second embodiment of the invention the bushing means, also preferably made from a plastics material is mountable to the saddle along two longitudinal lengths of the saddle.

Preferably the bushing means is mounted fixedly along one of the two longitudinal lengths and detachably along the other of the two longitudinal lengths, whilst the smaller pipeline is laid on an outer surface of the saddle between the two longitudinal lengths. When the bushing means is fitted over the smaller pipeline straps are passed around the larger pipeline and over the bushing means to secure the pipeline together with the saddle in between. This arrangement enables the straps to be secured tightly and there is less possibility of them working loose than in previous embodiments or prior art whilst allowing some axial movement between the pipelines.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a piggy back pipeline with a saddle according to one embodiment of the invention; Figure 2 is an end elevation of the saddle of Figure 1 as seen from A; Figure 3 is a perspective view of a bushing means for the saddle of Figure 1; Figure 4 is a perspective view of a piggy back pipeline with a saddle according to a second embodiment of the invention; and Figure 5 is an end elevation of the saddle of Figure 4 as seen from B.

In the piggy back pipeline arrangement shown in Figures 1 to 3 a large pipeline 2 is aligned parallel with a small pipeline 3. A saddle 4 made of a suitable elastomer or rubber is provided with a small pipeline encircling hole 5 (shown in broken lines in Fig. 2) and a large pipeline seating surface - 6, a slit 9 extends along the length of the saddle, substantially parallel to the axis 10 of the smaller pipeline from the ~exterior of the saddle to the encircling hole 5. The slit 9 can be provided at other positions in the saddle in alternative arrangements providing, of course, that the slit extends from the encircling hole 5 to some part of the exterior of the saddle.

A bush 12 or bushing means is shown in Figure 3 formed from two semi-cylindrical parts 13 and 14. The parts 13 and 14 abut along a line 15 which extends in a direction lengthwise of the bush so as to lie along a diameter of a circle centred on axis 10. At each end of the bush are flanges 16 which ensure that the bush is retained securely in the saddle 4.

The bush is made of a suitable plastics material such as hard nylon.

To insert a bush in the saddle it is merely necessary to open up the saddle at its slit 9 and insert the two halves of the bush or in the case of an alternative arrangement, the whole bush. The saddle with the bush inside can be then clipped on to a smaller pipeline in the normal way. Alternatively, in the case of the bush being made as a single part with only one axially aligned slit, this can be clipped onto the smaller pipeline. The saddle is then clipped or fitted over the bush.

In a second arrangment shown in Figures 4 and 5 a large pipeline 22 is aligned parallel with a small pipeline 23. A saddle 24 made of suitable elastomer or rubber is provided with a small pipeline seating surface 25 and a large pipeline seating surface 26.

A bushing member or means 32 is formed from a single part having along a first longitudinal edge an "L" shaped or hooked portion 33. This is moulded into the saddle to fix the first edge to the saddle along a first longitudinal line 34 or length of the saddle. On the second longitudinal edge of the member 32 the thickness of the member is enlarged to provide a thickened portion 36 which removably fits into a dovetailed slot 37 in the saddle extending along a second longitudinal line or length 38 of the saddle.

To assemble the arrangement, a saddle 24 with bushing member 32 secured at one edge is offered to the small pipeline 23 and the bushing member 32 is then bent round the small pipeline.

The unsecured other longitudinal edge of the bushing member with its thickened portion 36 is then fitted into slot 37 where it is sufficiently well secured to allow straps 40 to be placed round the larger pipeline 22 and the bushing member 32 so as to securely strap the smaller pipeline 23 within the bushing member 32 and seated on surface 25 of the saddle 24.

The saddle 24 is at the same time seated with its surface 26 on the larger pipeline. The straps 40 are then tightened so that the bushing means is firmly held to the larger pipeline but a certain degree of relative axial movement between the pipelines is allowable. This embodiment is advantageous in resisting relative twisting between the pipelines.

Claims

1. A piggy back pipeline saddle having a large pipeline seating surface, a small pipeline seating, and a bushing means securable to the saddle and which can be closed along its axial length to at least partly encircle the smaller pipeline.

2. A saddle according to claim 1 wherein the bushing means is mounted to the saddle by means of a smaller pipeline encircling hole in the saddle which is slit along a length of the encircling hole from the hole to the exterior of the saddle, the bushing means being fittable within the hole.

3. A saddle according to claim 1 or claim 2 wherein the bushing means is formed as two halves.

4. A saddle according to claim 1 in which the bushing means is mountable to the saddle along two longitudinal lengths of the saddle.

5. A saddle according to claim 4 in which the bushing means is mounted fixedly along one of the two longitudinal lengths and detachably along the further of the two longitudinal lengths, a smaller pipeline being locatable on the small pipeline seating between the two longitudinal lengths.

6. A saddle according to claim 5 wherein a longitudinal slot is provided along said further of the two longitudinal lengths# for accepting a first longitudinal edge of the bushing means.

7. A saddle according to claim 6 wherein the first longitudinal edge of the bushing means is formed with a thickened edge portion and wherein the slot is dovetailed.

8. A saddle according to any one of claims 4 to 7 wherein a second longitudinal edge of the bushing means is fixedly secured to the saddle by means of a hooked portion.

9. A saddle according to any one of claims 1 to 8 wherein a bushing means is provided with flanges at each end.

10. A piggy back pipeline saddle substantially as described with reference to Fig.s 1 to 3 or Fig.s 4 and 5 of the drawings.