GB2339253A

GB2339253A - A coupling arrangement

Info

Publication number: GB2339253A
Application number: GB9913569A
Authority: GB
Inventors: Nicholas John Stuart White
Original assignee: GEORGE FISCHER SALES Ltd
Current assignee: GEORGE FISCHER SALES Ltd
Priority date: 1998-06-11
Filing date: 1999-06-11
Publication date: 2000-01-19
Anticipated expiration: 2019-06-11
Also published as: GB2339253B; GB9913569D0; GB9825574D0

Description

2339253 PIPE FITTINGS The present invention relates to a pipe fitting for

joining a pipe to a f ixed f itting or another pipe and to a method and meaning for repairing a pipe.

When coupling pipes or pipes together conventional couplings normally consist of a f irst element gripping the pipe to be coupled and a second element which fastens to the fixed fittings or other pipe for brevity the fixed fitting, other pipe or other element to be connected will be referred to as "the second connection elemently.

The first element is often secured to this second connection element by screwing the first element relatively onto this second second connection element.

Torque on tightening up is normally taken up a washer or merely by the inherent lack of friction between the elements.

However, when coupling flexible piping such as polyethylene (PE) gas piping the coupling torque can twist the piping. This can result in excessive stress or else uncoupling at the other end of the pipe.

Accordingly the invention provides a coupling comprising a first coupling element and a second coupling element, the first coupling element adapted to screw to the second element, a first part adapted to fit at least partially around a conduit between the first and second coupling elements, the first part being locatable between the first and second coupling elements so as to engage non-rotationally with the second coupling element with an abutment face on the first part being designed to slip rotationally with respect to the first element on screwing the coupling elements together.

2 Preferably the first coupling element is a male element and the second coupling element is a female element, the non-rotatable connection between the first part and the female element being a slot and lug arrangement.

The problem of torque reduction in joints is particularly applicable to an arrangement for repairing a pipe as set out in our copending British Patent Application No 9816272.0 because the corrugated pipe used as an insertion into and for repairing existing pipe is necessarily thin and cannot stand much torque.

Accordingly in a preferred embodiment the coupling of the invention has as the second coupling element an adaptor being adapted to connect to an existing pipe at one end and the first coupling element at the other end, the adaptor being arranged to fit around a corrugated pipe inserted into the existing pipe and being further arranged to clamp onto the corrugated pipe by means of a compression sealing means engaging with corrugations at the corrugated pipe, engagement being ensured by screwing the first coupling element to the second coupling element. The first part is preferably housed non-rotationally in the adaptor, nonrotation being preferably ensured by means of a slot and lug arrangement.

The invention also concerns a method of repairing a pipe such as a gas or water pipe comprising inserting corrugated pipe into an existing pipe, fitting an adaptor over the corrugated pipe and securing the adaptor to the existing pipe, compressing a compression ring within the adaptor onto the corrugated pipe, the ring having at least one radially inwardly extending portion arranged to engage with corrugations of the corrugated pipe, a first part being non- rotationally secured to the adaptor acting to compress the compression ring on screwing a coupling element onto the adaptor acting as a further coupling element.

3 The invention will now be described with reference to the accompanying drawings in which:Figure 1 is a longitudinal parts sectional view of the 5 coupling according to a first embodiment of the invention, Figure 2 is an elevation of a second coupling part of the coupling shown in Figure 1, Figure 3 is a longitudinal cross-section of an adaptor secured to an existing pipe according to the invention, Figure 4 is a diametric crosssection of a sealing ring shown in Figure 3, 15 Figure 5A is a plan view of a washer fitted in the body of the adaptor of Figure 3 between the nipple and sealing ring of Figure 4. Figure 5D is a diametral crosssection of the washer of Figure 5A taken at A-A of Figure 5A, 20 Figure 6 shows in six diagrammatic views how the adaptor of Figure 1 is secured and an existing pipe is repaired and Figure 7 is a combined coupling of those of Figures 1 and 25 3.

The coupling shown in Figure 1 and 2 has a f irst and male coupling element 101 second and female coupling element 102.

Both coupling elements surround conduit formed by pipe 103 into an end of which is a standard insert 104. Between the coupling elements 101 and 102 is a first part 105 having a lug 106 extending therefrom, a second part 107, a third part 109 and a fourth part ill.

4 The first part 105 is formed with lug 106, a planar abutment surface 121 and a conical abutment surface 123. The planar surface 121 abuts planar surface 119 of first coupling element 101. The conical surface 123 abuts conical surface 12S of a split internally toothed locking ring 107 which forms the second part.

The second part 107 has a planar abutment surface 127 which abuts on washer 109 forming the third part. The washer 109 in turn abuts on a nitrile rubber flexible ring ill (to ES2494 G) forming the fourth part, a conical abutment surface 129 of which abuts on conical surface 131 of coupling element 102.

Coupling or male element 101 screws by means of its external thread 115 into the second or female element 102 by means of its internal thread 117.

To couple up, fit insert 104 into one end of pipe 103, then fit element 101 and parts 105, 107, 109 and 111 onto pipe 103 as shown in Figure 1. Then screw element 101 into element 102 with lug 106 engaging in longitudinal slot 113. As elements 101 and 102 tighten, part 107 crushes onto pipe 103 in the region of metal insert 104. As element one turns on pipe 103, abutment surfaces 119 and 121 mutually engage and slip rotatingly to avoid any transfer of torque as far as possible from element 10 to pipe 103. This avoids twisting PE pipe 103.

The adaptor 1 shown generally in Figure 3 has a body 2 which by means of an internal thread 4 at one end 5 has been screwed to an existing steel service pipe 3 which is defective. At the other end 6 there is another internal thread 7 which receives an adaptor body nipple 8. The nipple and body comprise an adaptor fitting.

within the body 2 is a chamber 10 having a first chamfered abutment edge 12 onto which seats a sealing means formed as a compression ring seal 14 shown in more detail in Figure 4.

Seated in turn on the ring seal 14 is a shaped washer 30 shown in more detail in figures 5A and 5B. The washer has a chamfered inner face 32 which seats on the outer face 22 of seal 14 and a lug 34 which fits in a slot 3G in the adaptor body so as to prevent rotation of the washer 30. The purpose of the lug and slot arrangement which incidentally could be reversed so that there was a flat or slot in the washer engaging with a projection from the adaptor body, is to prevent any torque being transmitted from the nipple 8 through the adaptor and thence to the pipe 16.

The washer is suitably made from Polyacetal POM (Polyoxymethyiene).

The nipple 8 has an abutment surface 15 so that the ring seal lies between the edge 12 and surface 15 with the washer outer surface 38 abutting on surface 15.

Inserted into the body is a corrugated polyethylene pipe 16 into which a stiffener tube 17 has been inserted.

2n The body also has a grout insertion inlet 20 into which a form grout is forced so as to lie between pipes 3 and 1G. The sealing compression ring seal 14 shown in Figure 4 has abutment edges 21 and 22 corresponding respectively to abutment 25 edges 12 and 32. Internally and extending radially inwards are portions 23 and 24 which extend completely around the inside of the ring and which correspond in size and pitch to the corrugations 26 of pipe 1G. The ring seal is formed of nitrile rubber of 66 - 75 1. R. H. D. Hardness (B. S. 24 94 (G)). When compressed 30 by screwing nipple 8 into body 2 the portion 23 and 24 are compressed into engagement with the pipe 1G. Figure 6 shows various stages of fitting and corrugated pipe 16 to pipe 3 to repair the pipe 3 when defective. Figure 6 (1) shows 35 corrugated pipe 1G inserted into pipe 3. At Figure 6 (2) the pipe 16 is cut to size using the adaptor body as a gauge. In Figure 6(3) the stiffener tube 17 is inserted and in Figure G(4) the 6 adaptor 1 is f itted over the pipes 3 and 16 and secured by screwing the adaptor 1 onto pipe 3. The nipple is then tightened as shown in Figure 6(5) to lock the ring seal 14 onto the pipe 16. In Figure 6(6) the adaption is complete and grout is then pumped into inlet 20 to completely repair the pipe 3. The main seal between the pipes is by means of ring seal 14. The grouting is an additional precaution.

Several types of sealing means have been tried, notably a ring seal formed of a pair of 101 rings. However, this arrangement, despite compression, did not apply as high an end load on the corrugated pipe as did ring seal 14. Nevertheless, this arrangement is within the scope of the invention. Furthermore, it should be possible to form a ring which is split but which seals under pressure. The ring may be f ormed of any suitable material including possibly a gel material.

It will be appreciated that coupling element 102 of Figure 1 can be screwed by means of thread 132 onto adaptor 1 instead of nipple 8. 101 ring 133 housed in end recess 134 then abuts on washer 30. This arrangement is shown in Figure 7 where pipe 103 is joined to pipe So and adaptor 1 has a male thread 51. This is known as a "Garden Fitting".

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Claims

1 A coupling comprising a first coupling element and a second coupling element, the first coupling element adapted to screw to the second element, a first part adapted to fit at least partially around a conduit between the first and second coupling elements, the first part being locatable between the first and second coupling elements so as to engage non-rotationally with the second coupling element with an abutment face on the first part being designed to slip rotationally with respect to the first element on screwing the coupling elements together.

2. A coupling as claimed in claim 1, wherein the first coupling element is a male element and the second coupling element is a is female element, the non-rotatable connection between the first part and the female element being a slot and lug arrangement.

3. A coupling as claimed in claim 1 or 2, wherein the second coupling element is an adaptor adapted to connect to an existing pipe at one end and the first coupling element at the other end, the adaptor being arranged to fit around a corrugated pipe inserted into the existing pipe and being further arranged to clamp onto the corrugated pipe by means of a compression sealing means engaging with corrugations of the corrugated pipe, engagement being ensured by screwing the first coupling element to the second coupling element.

4. A coupling as claimed in claim 3 wherein the first part is housed nonrotationally in the adaptor, non-rotation being ensured by a slot and lug arrangement.

5. A coupling as described with reference to any use or more of the accompanying drawings.

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6. A method of repairing a pipe such as a gas or water pipe comprising inserting corrugated pipe into an existing pipe, fitting an adaptor over the corrugated pipe and securing the adaptor to the existing pipe, compressing a compression ring within the adaptor onto the corrugated pipe, the ring having at least one radially inwardly extending portion arranged to engage with corrugations of the corrugated pipe, a first part being nonrotationally secured to the adaptor acting to compress the compression ring on screwing a coupling element onto the adaptor 10 acting as a further coupling element.