GB2361273A

GB2361273A - A method of sealing a pipe joint

Info

Publication number: GB2361273A
Application number: GB0011447A
Authority: GB
Inventors: Stanley John Peacock; Peter Michael Wardle
Original assignee: Chemence Ltd
Current assignee: Chemence Ltd
Priority date: 2000-04-15
Filing date: 2000-05-15
Publication date: 2001-10-17
Also published as: GB0011447D0; GB0009254D0

Abstract

A method for sealing a pipe joint formed between an externally threaded spigot 4, 5 and an internally threaded socket 1 in which the spigot is screw fitted, the method comprising drilling a hole through the wall of the socket to a depth permitting the hole to communicate with the threads of the spigot and injecting a settable liquid sealant through the hole into the threads. Preferably the method is for use in stopping and repairing a leak formed in screwed joints. The hole may be formed by drilling, and the sealant used may be an anaerobic sealant.

Description

2361273 Title: A Method for Sealing a Pipe-Joint The present invention

relates to a method for sealing a pipe-joint formed between an externally threaded spigot and an internally threaded socket to which the spigot is screw fitted.

Screwed joints formed between spigots and a sockets of the above type and carrying a lluid such as gas or water under pressure for instance in dwellings can develop a leak or leaks between the adjoining threads of the spigot and socket. Gas or water as the case may be can then escape from the pipe through the leak path or paths so formed.

A common method for stopping and repairing such leaks is to encapsulate the pipe'joint in an annular jacket of a settable mastic sealant which is caused to adhere to and set on the pipe wall. As rather a large amount of mastic material is necessary for this technique to be eflective it is somewhat expensive and it is an object of the present invention to provide an elftective method for sealing pipe-joints of the type defined but which is cheaper than the current encapsulation technique.

According to the present invention, we provide a method for sealing an externally threaded spigot and an internally threaded socket in which the spigot is screw fitted, the method comprising forming a hole in the wall of the socket to a depth permitting the hole to communicate with the threads of the spigot and injecting a settable liquid sealant into the hole and into the threads of the spigot.

Preferably, the hole is formed by drilling through the wall of the socket.

Suitably, after the sealant has been injected the hole is closed.

Conveniently, after the hole has been drilled it is tapped and after the sealant has been injected the tapped hole is closed by a grub screw.

Preferably, the sealant is injected by means of a syringe.

1 7 1 Suitably, the sealant is an anaerobic sealant.

An embodiment of the invention will now be particularly described with reference to the accompanying drawings in which:

Figure 1 is a longitudinal section through a pair of threaded pipe joints formed of two spigots and a socket showing one of the joints in the process of being sealed and Figure 2 is an amplified version of the joint in the process of being sealed.

Referring to the drawings, in Figure 1 a steel socket-type pipe 1 has an internally threaded portion at either of its ends 2 and 3. Two spigottype steel pipes 4 and 5 have externally threaded portions 6 and 7 which are respectively screwed into the ends 2 and 3 of the socket-type pipe 1. The pipes 1, 4 and 5 may be service pipes carrying gas or water under pressure to a domestic dwelling and a leak has been detected in the joint 8 between the spigot 4 and the socket 1. This leak may have been detected by smell in the case of gas or with an instrument.

Initially, a hole is drilled through the wall of the threaded socket portion 2. In the drawings this has already been done. In a typical service pipe socket with an internal diameter of 3 1 nin- the diameter of the hole could be 3.3nun and, in use, the drill should be caused to encounter the threads of the spigot portion 6 to ensure that the hole communicates with the threads. The drill may actually be allowed slightly to penetrate the threads of the socket portion 6 to confirm that this communication has occurred. All swarf formed on drilling should be removed after the hole has been formed.

After the hole has been formed, it is tapped with a suitable tap e.g. a 4mm tap (already done in the drawings) and again all swarf formed should be removed.

Next, the sealant is injected into the threads by way of the hole. The sealant is a liquid settable sealant such as an anaerobic type sealant because this has been found to produce good results. A suitable sealant is Chemence Ritelok (Trade Mark) TL 90 anaerobic thread sealant.

2 As shown in Figure 1, the sealant is contained in and injected by a syringe 9 which in this case is made entirely of a plastic material e.g. polyethylene. The syringe 9 has a chamber 10 for the sealant 11, a plunger 12 and an injection tube 13. While not shown, the end of the injection tube 13 is initially provided with a protective cap also of polyethylene which cap is removed for use and the tube 13 is inserted into a container (not shown) of the sealant with the plunger 12 depressed. When the plunger 12 is then raised the sealant is then sucked up into the chamber 10. The syringe injection tube 13 is then wiped clean of any surplus sealant and the syringe tube 13 is them screwed into the tapped hole by a self-tapping type of process whereby the position shown in the drawings is attained. The plunger 12 is then gently depressed to discharge the contents of the chamber 10 into the joint 8. As anaerobic sealant is a relatively quick setting sealant the leak should be stopped relatively quickly. Once the leak has been scaled a suitable grub screw (not shown) can be screwed into the hole to complete the job. Sealant remaining in the tapping will seal the grub screw and prevent leakage.

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Claims

1. A method for sealing a pipe joint formed between an externally threaded spigot and an internally threaded socket in which the spigot is screw fitted, the method comprising forming a hole in the wall of the socket to a depth permitting the hole to communicate with the threads of the spigot and injecting a settable liquid sealant into the hole and into the threads of the spigot.

2. A method as claimed in claiml in which the hole is formed by drilling through the wall of the socket.

3. A method as claimed in claim 1 or claini2 in which after the sealant has been injected the hole is closed.

4. A method as claimed in either claim 2 or claim 3 in which after the hole has been drilled it is tapped and after the sealant has been injected the hole is closed by a grub screw.

5. A method as claimed in any of claims 1 to 4 in which the sealant is injected by means of a syringe.

6. A method as claimed in any of the preceding claims in which the sealant is an anaerobic sealant.

7. A method substantially as hereinbefore described with reference to the accompanying drawings.

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