GB2120150A - Pipe spacer - Google Patents

Abstract

A pipe spacer 10 is positioned between the end 22 of a pipe 20 and an internal annular shoulder 26 of a bore of a fitting 24, into which bore the pipe is inserted prior to welding the pipe to the fitting at 28. The spacer 10 comprises a ring-shaped body 12 which is split, at 14, to define a pair of spaced ends 18. The body 12 is formed with three, equi-spaced resilient protrusions 16 which serve to increase the effective thickness of the spacer 10. The body 12 has an outer diametrical dimension approximately equal to the outer diametrical dimension of the pipe 20, whereby the body abuts either the pipe end 22 or the fitting shoulder 26 at the regions of the protrusions 16. The protrusions 16 are sufficiently compressible to maintain a spacing between the pipe 20 and the fitting shoulder 26 during pipe expansion resulting from welding the pipe to the fitting 24. The spaced body ends 18 are spaced sufficiently apart to accommodate circumferential expansion of the body 12, to prevent abutment of the spaced body ends during the pipe expansion as the protrusions 16 are compressed. <IMAGE>

Description

SPECIFICATION Pipe spacer This invention relates to a spacer which is used to separate two pieces of metal which are to be welded together, and in particular to maintain the separation of a pipe and the internal shoulder of the bore of a fitting to which the pipe is to be welded.

Upon welding a pipe to such a fitting the pipe expands; and, unless the pipe is kept from contacting the fitting shoulder, the expansion can cause the fitting or the weld to crack.

The aim of the invention is to provide a spacer which will reliably separate a pipe end and a fitting shoulder during welding.

The present invention provides a spacer for positioning between the end of a pipe and an internal annular shoulder of a bore of a fitting into which bore the pipe is inserted prior to welding the pipe to the fitting, the spacer comprising a ring-shaped body which is split to define a pair of spaced ends, the body being formed with at least one resilient protrusion which serves to increase the effective thickness of the spacer, the body having an outer diametrical dimension approximately equal to the outer diametrical dimension of the pipe, whereby, in use, the body abuts either said pipe end or the fitting shoulder at the region of the or each protrusion, wherein the or each protrusion is sufficiently compressible to maintain a predetermined spacing between the pipe and the fitting shoulder during pipe expansion resulting from welding the pipe to the fitting, and wherein said spaced body ends are spaced sufficiently apart to accommodate circumferential expansion of the body to prevent abutment of said spaced body ends during said pipe expansion as the or each protrusion is compressed.

This form of spacer will, therefore, reliably separate the pipe end from the fitting shoulder during welding. Moreover this spacer is easy to make and use, and is effective to prevent weld cracking between the pipe and the fitting during welding.

Advantageously, the spacer body is provided with three equi-spaced protrusions. This helps to ensure that the spacer will maintain the proper alignment of the pipe within the fitting during welding. Conveniently, the spacer body has a non-circular cross-section, the body having a pair of opposite flat surfaces and being substantially coplanar apart from the or each protrusion.

Preferably, the spacer is made of metal or of a material that is soluble in a liquid such as water.

In a preferred embodimant, the spacer body is provided with a tab which projects substantially at right angles to the plane of the spacer body so that, in use, the tab extends between the fitting and the pipe and projects beyond the fitting to indicate the presence of the spacer when positioned between said pipe end and the fitting shoulder. The tab thus provides a visible indication for ascertaining that the joint incorporates a spacer. Preferably, the tab is made of a light-weight material such as paper or thin flexible plastics material.

Alternatively, where the spacer is made of metal, the tab may be made of metal and be formed integrally with the spacer body.

Preferably, the outer diametrical dimension of the spacer body exceeds the outer diametrical dimension of the bore in the fitting, the spacer body being sufficiently resilient to enable the spacer body to be fitted within said bore.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:~ Figure 1 is a perspective view of a first form of spacer constructed in accordance with the invention; Figure 2 is a part-sectional side elevation of a pipe and a fitting prior to welding with the spacer of Fig. 1 inserted therebetween, and with the pipe tacked to the fitting; Figure 3 is a part-sectional side elevation similar to that of Fig. 2, but showing the relative positions of the parts during welding; Figure 4 is a perspective view of a second form of spacer constructed in accordance with the invention; Figure 5 is a part-sectional side elevation of a pipe and a fitting prior to welding, with the spacer of Fig. 4 inserted therebetween;; Figure 6 is a part-sectional side elevation similar to that of Fig. 5, but showing the relative positions of the parts after welding; Figure 7 is a perspective view of the welded pipe/fitting arrangement of Fig. 6 as seen from below; and Figure 8 is a perspective view of a third form of spacer constructed in accordance with the invention.

Referring to the drawings, Fig. 1 shows a spacer 10 which has a flattened ring-shaped body 12. The body 12 is formed with a split 1 4 which defines a pair of spaced ends 18.

The body 12 is also formed with three protrusions 16. The spacer 10 is made from a flexible material, such as stainless steel welding wire, to allow the protrusions 16 to be compressed.

Fig. 2 shows the spacer 10 within a fitting 24 to which a pipe 20 is to be welded. The spacer 1 O is positioned against an internal shoulder 26 formed within the fitting 24, and the pipe 20 is then inserted into the fitting, so that the pipe end 22 contacts the spacer with the spacer being lightly compressed between the pipe and the shoulder 26 of the fitting.

The pipe 20 is tacked to the fitting 24 in preparation for welding.

The protrusions 16 of the spacer 10 serve to align the pipe 20 with the fitting 24, and to space the pipe end 22 from the fitting shoulder 26 in preparation for welding the pipe and fitting together. The protrusions 1 6 have the same height, and are equi-spaced around the spacer body 12, so that the spacer 10 can assume a substantiaily precise transverse orientation within the fitting 24.

Fig. 3 depicts the positions of the spacer 10 and the pipe 20 as a weld 28 is formed between the pipe and the fitting 24. During this welding, the pipe 20 expands due to heat, as depicted by the arrow 29. This expansion causes partial compression of the protrusions 16, with a resulting circumferential expansion of the spacer body 12. This circumferential compression of the spacer body 12 is allowed by the distance between the ends 18 of the spacer 10 defined by the slit 14. Additionally, there may be a slight diametrical expansion of the spacer body 12 if there is an initial diametrical clearance of the spacer 10 within the fitting 24.

The height of each protrusion 16, as measured between a face 17 of the spacer body 12 and the top of that protrusion, is designed to exceed the calculated maximum expansion of the pipe 20 and the fitting 24, so that the protrusions will never be compressed far enough to permit noncompressive contact between the pipe, the spacer and the fitting.

Figs. 4 and 5 shows a modified spacer 10 having a locating tab 30. The tab 30 is preferably formed of paper or of a light filmlike plastics material, and has an adhesive 33 applied to one side. One end of the tab 30 is secured around the body 12 of the spacer 10, preferably at a protrusion 16, so that the tab extends generally at a right-angle to the spacer. Prior to insertion of the spacer 10 within the pipe 20, a removable cover material (not shown) will be applied over the adhesive backed side of the tab.

In use, the spacer 10 carrying the tab 30 is placed into the fitting 24, and positioned against the shoulder 26 before the insertion of the pipe 20, as previously described for the embodiment of Figs. 1 to 3. The tab 30 is preferably positioned with its adhesive backed side facing the centre of the fitting 24, so as to be located against the outside surface 21 of the pipe 20 when the pipe is inserted into the fitting, as seen in Fig. 5. Prior to the insertion of the pipe 20 into the fitting 24, the adhesive cover applied to the tab 30 is removed, the tab is bent downwardly around the end of the fitting 24, and is held until the pipe is fully inserted into the fitting with the pipe end 22 contacting the spacer 10 at the protrusions 16.The tab 30 is then released, and brought to bear against the outside surface 21 of the pipe 20 at its adhesive backed side, so as to be attached to the pipe. When the spacer 10 is seated within the fitting 24, the length of the tab 30 is sufficient to allow the tab to extend beyond the fitting, and to be visible along the length of the pipe 20 for a distance of approximately one to two inches, depending upon the pipe size. If desired, the tab 30 could be turned back around the end 27 of the fitting 24, and adhered to Ihs outer surface of the fitting in preparation for weld ing. In this case, the tab 30 would have an adhesive applied to both of its sides.

The pipe 20 is then tacked, at 2.6, to the fitting 24 in preparation for welding. When the pipe 20 is fully welded to the fitting 24, the tab 30 will be burnt away at the location of the weld, so as not to interfere with the integrity of the weld. The remaining end 31 of the tab 30 remains attached to the exterior of the pipe 20 or to the fitting 24, as the case may be, as a visible reminder that the spacer 10 was utilised within the fitting during the welding process. In this manner, the presence of the spacer 10 can be verified by quick visual observation, without the necessity of a confirming x-ray of the joint.

Although the tab 30 has been described in this embodiment as being made of paper, or a thin flexible plastics material, it will be appreciated that it could be made of a material having a similar light-weight construction. It is also contemplated that the tab 30 may be formed of the same material as the spacer 10, in which case it would simply be an outturned extension 32 which projects laterally from one end 18 of the spacer body 1 2, as seen in Fig. 8.

In each of the embodiments described above, the spacer 10 is intended to remain within the fitting 24 after the pipe 20 has been welded thereto. There are no spacer parts which project into the passage (or flow path) through the connected pipe and fitting.

Normally, the radial expansion of the spacer 10 within the fitting 24 prior to welding will serve to retain the spacer. However, in order to be certain that the spacer 10 does not fall out of, or become jarred loose from, the fitting 24 after being inserted (such as could occur during transportation, or movement of the fitting to the weld location), it may be preferable to tack-weld the spacer to the fitting. This is preferably done at the location between the internal shoulder 26 of the fitting 24 and at (or near) the flat of a protrusion 16 of the spacer 10. By being tacked at only one location, the spacer 10 is free to expand during compressive loading between the pipe 20 and the fitting 24 as welding takes place.

While, in the preferred embodiments, the spacer 10 is described as being made of metal, it is to be understood that the spacer may be made of a material which is soluble in water or other liquid; and which retains sufficient rigidity to perform is spacing function.

After welding of the pipe 20 to the fitting 24, and the introduction of a suitable liquid through the pipe, however, the material from which the spacer 10 is made will dissolve and be flushed from the system. When using a liquid soluble spacer, a tab 30 may be utilised as an indicator for determining the presence of the spacer during welding.

Claims (10)

1. A spacer for positioning between the end of a pipe and an internal annular shoulder of a bore of a fitting into which bore the pipe is inserted prior to welding the pipe to the fitting, the spacer comprising a ring-shaped body which is split to define a pair of spaced ends, the body being formed with at least one resilient protrusion which serves to increase the effective thickness of the spacer, the body having an outer diametrical dimension approximately equal to the outer diametrical dimension of the pipe, whereby, in use, the body abuts either said pipe end or the fitting shoulder at the region of the or each protrusion, wherein the or each protrusion is sufficiently compressible to maintain a predetermined spacing between the pipe and the fitting shoulder during pipe expansion resulting from welding the pipe to the fitting, and wherein said spaced body ends are spaced sufficiently apart to accommodate circumferential expansion of the body to prevent abutment of said spaced body ends during said pipe expansion as the or each protrusion is compressed.

2. A spacer as claimed in claim 1, wherein the spacer body is provided with three equi-spaced protrusions.

3. A spacer as claimed in claim 1 or claim 2, wherein the spacer body has a non-circular cross-section, the body having a pair of opposite flat surfaces and being substantially coplanar apart from the or each protrusion.

4. A spacer as claimed in any one of claims 1 to 3, wherein the spacer is made of metal.

5. A spacer as claimed in any one of claims 1 to 3, wherein the spacer is made of a material which is soluble in a liquid such as water.

6. A spacer as claimed in any one of claims 1 to 5, wherein the spacer body is provided with a tab which projects substantially at right angles to the plane of the spacer body so that, in use, the tab extends between the fitting and the pipe and projects beyond the fitting to indicate the presence of the spacer when positioned between said pipe end and the fitting shoulder.

7. A spacer as claimed in claim 6, wherein the tab is made of a light-weight material such as paper or thin flexible plastics material.

8. A spacer as claimed in claim 6 when appendent to claim 4, wherein the tab is made of metal and is formed integrally with the spacer body.

9. A spacer as claimed n any one of claims 1 to 8, wherein the outer diametrical dimension of the spacer body exceeds the outer diametrical dimension of the bore in the fitting, the spacer body being sufficiently resilient to enable the spacer body to be fitted within said bore.

10. A spacer substantially as hereinbefore described with reference to, and as illustrated by, Figs. 1 to 3, Figs. 4 to 6, or Fig. 8 of the accompanying drawings.