GB2281584A

GB2281584A - A pipeline strap having a protective covering

Info

Publication number: GB2281584A
Application number: GB9318249A
Authority: GB
Inventors: Michael Wyn Harold
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-09-02
Filing date: 1993-09-02
Publication date: 1995-03-08
Also published as: GB9318249D0

Abstract

A strap 1 that protects an anti-corrosion coating on a pipeline is used to secure a piggy-back pipeline saddle to a pipe and comprises a metal strapping 2 covered along part of its length with a protective covering 3, eg rubber or plastics, which enables the strapping to be gripped on an uncovered portion 7 by a strapping machine whilst the covered part 5 protects the pipeline. A crimping seal 10 is retained on the strap 1 either by folding over end portion 4 or by extensions (13, fig 4) of the covering 3 projecting beyond the width of the strapping 2. The strap 1 is supplied with the seal 10 attached and in use the covered part 5 is placed around outer surface of the pipeline and part of the saddle. The portion 7 is inserted into seal 10, crimped into the seal and, if necessary, trimmed to an end 9. <IMAGE>

Description

STRAPPING The present invention relates to strapping for but not restricted in use with piggy back pipeline saddles.

A piggy back pipeline saddle and the arrangement whereby the saddle made from a suitable elastomer or rubber is interposed between a large pipeline and a small parallel pipeline is well known. A particular such saddle is shown in my patent publication GB 2 247 730 A. In order to clamp the saddle to the large pipeline a metal strap or strapping is passed around the saddle and large pipeline tightened by means of a strapping machine and secured by a seal crimped around the ends of the strap. After the strap is secured the pipelines are fed from the laying vessel to the sea bottom. In order to protect the large pipeline from corrosion the large pipeline is during manufacture coated with a protective material. Whilst applying the strap to the pipeline and during the laying operation there is a tendency for the strapping to shift slightly in relation to the large pipeline and so damage the protective coating of the large pipeline. Whereas it might appear simple to wrap the large pipeline with protective material at each strapping position, this operation would be time consuming and difficult to achieve in a seaway. Furthermore, if the whole strap was covered or coated with protective material this would result in problems when tensioning. That is the tensioning machine would not be able to grip the strap effectively.

Accordingly a strap according to the invention comprises a length of metal strapping covered along only a part of the length with a protective material on at least one side of the strapping.

The strap of the invention is then passed around the large pipeline and saddle so that the covered part lies with the covering against and partly around the large pipeline, the uncovered part of the strapping extending over at least part of the saddle to a seal preferably retained on the strap at the covered end.

In order to ensure the seal is retained at the covered end the covering preferably extends for a small length beyond the width of the strip. The strapping is preferably formed back from that end toward the other end so as to trap the seal between two parts of the strapping to enable tensioning. In order to ensure the covered end when so formed back does not have any metal portions which could rub against the large pipeline both opposed major sides of the strapping are covered with a protective material for a length corresponding at least to the length of the formed back portion.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a cross section of a large pipeline with saddle and two small pipelines supported on the saddle, the saddle and large pipelines strapped together with a strap, according to the invention, Figure 2 is a cross section of a strap according to the invention before final formation, Figure 3 is a cross section of the strap of Fig. 2 with an end folded under the seal in its final formation, and Figure 4 is a plan view of the folded end of the strap of Fig. 4.

In Figure 2 a strap 1 is shown prior to its final formation which comprises a metal strip 2 1300 mm long by 32 mm wide made of a suitable corrosion resistive material. Covering 3 of rubber or an elastomeric plastics material extend on both major opposed sides of the strip for a length of 100 mm at one end portion 4. The covering 3 then extends on one of the said sides only of the strip for 700 mm along a portion 5 to a point 6 where the covering ceases and the remaining 500 mm of the strip along a portion 7 is uncovered so that it may be gripped by a tensioning machine.

To complete the formation of the strap as is shown in Fig.

3 seal 10 of known construction which is threaded onto the covered end of the strip is trapped onto the strip by folding over end portion 4. In Fig. 4 extensions 13 of the covering 3 extend beyond the width of the strip for a small length in order to retain the seal 10.

The strap so formed as in Fig. 2 is then supplied to a laying vessel where and as shown in Figure 1 the strap is placed around a large pipeline 12 of 225 mm overall diameter with the covering 3 of the covered portion 5 against the outer surface of pipeline 12 and over part of saddle 14 which carries two small pipelines 16 of 25.4 mm overall diameter. The uncovered portion 7 is then inserted into seal 10 tensionl ,crimped into the seal and if necessary trimmed to an end 9.

Claims

CLAIMS:

1. A strap comprising a length of metal strapping covered along only a part of the length with a protective material on at least one side of the strapping.

2. A strap as claimed in claim 1 wherein one end of the strapping is covered by the protective material on at least one side.

3. A strap as claimed in claim 2 wherein the protective material at one end covers both sides of the strapping.

4. A strap as claimed in claim 2 or 3 wherein a seal is retained on the strap at said one end.

5. A strap as claimed in claim 4 wherein the seal is retained on the strapping by the covering protective material extending for a length beyond the width of the strap near said one end.

6. A strap as claimed in claim 4 or 5 wherein the strapping is formed back from said one end towards the other end so as to trap the seal between two parts of the strapping.

7. A strap as claimed in claim 6 wherein both sides of the strapping are covered with the protective material on both opposed sides for a length at said one end corresponding at least to the length of the formed back portion.

8. A strap substantially as described with reference to the accompanying drawings.

9. A piggy back pipeline having a strap as claimed in any of claims 1 to 8.

10. A piggy back pipeline substantially as described with reference to the accompanying drawings