GB2569277A

GB2569277A - Pipe joint seal fitting

Info

Publication number: GB2569277A
Application number: GB1717374.1A
Authority: GB
Inventors: Carrington Paul; Talbot Christopher Richard
Original assignee: Aquacheck Engineering H Ltd
Current assignee: Aquacheck Engineering H Ltd
Priority date: 2017-10-23
Filing date: 2017-10-23
Publication date: 2019-06-19
Anticipated expiration: 2037-10-23
Also published as: GB201717374D0; GB2569277B

Abstract

A pipe joint seal fitting 1 for connecting a first pipe 2 (e.g. lined pipe with lining 3) to a second pipe or to a pipe connector comprising: a body part 4 defining a passageway 5 therethrough and an internal shoulder 6, a first part 7 of the body is adapted to fit externally around an end of the first pipe and on the other side of the shoulder a second part 8 of the body is adapted to be connected to the second pipe; an insert 12 adapted to locate, in use, between the first part of the body 7 and the exterior of the first pipe 2 and defining an annular channel (14) in which the end of the first pipe locates; a first gasket 16 located between the internal shoulder 6 and the insert; a second gasket 17 located between the insert and the exterior of the first pipe; and a clamp 19, 20 adapted to secure the first part of the body to the first pipe and thereby compress the first and second gaskets to form seals respectively over the end of the first pipe and around the outside of the first pipe.

Description

The present invention relates to a pipe fitting for sealing a joint between first and second pipes or between a first pipe and a pipe connector. The pipe fitting is primarily intended for use to prevent gas tracking between the first pipe and a material lining the first pipe.

Utility pipelines such as those used to carry gas supplies are usually buried underground and therefore difficult to access for repair and maintenance work. They are also susceptible to corrosion over time. It is therefore usual to cover the interior surface of the pipeline with an impermeable lining material in order to extend the life of the pipeline. Such lining material may be a resin that is sprayed over the interior surface of the pipeline in a liquid form and that then cures to form the impermeable lining or it may be a length of plastics piping that is inserted into the existing pipeline to form a lining. In either case, the end result is effectively a pipeline that consists of a pipe within a pipe. However, where a lined pipeline enters a user’s premises, the lined pipe at the end of the pipeline is usually connected to a meter or to internal pipework and a seal has to be created between them. The problem with conventional seal fittings used for this purpose is that while they may seal the joint between the lined pipe and a pipe connector or other internal pipework, they do not seal the joint between the lining and the outer pipe. This makes it possible for fluid, typically gas, to seep back along the external pipe between the lining and the outer pipe. This is called “gas tracking” in the gas industry and if the outer pipe is breached at any point, for example owing to corrosion, the gas or other fluid can then leak out into the environment. This is particularly dangerous if the gas is a natural gas, which primarily comprises methane. In addition, if work has to be carried out on the internal pipework or gas meter, disconnection of the internal pipework or meter from the seal fitting can cause damage to the integrity of the pipe lining and the seal between it and the seal fitting.

An object of the present invention is to overcome or substantially mitigate the aforementioned problems

According to the present invention there is provided a pipe joint seal fitting for connecting a first pipe to a second pipe or to a pipe connector comprising a body part defining a passageway therethrough and an internal shoulder such that on one side of the shoulder a first part of the body is adapted to fit externally around an end of the first pipe and on the other side of the shoulder a second part of the body is adapted to be connected to the second pipe;

an insert adapted to locate, in use, between the first part of the body and the exterior of the first pipe and defining an annular channel in which the end of the first pipe locates;

a first gasket located between the internal shoulder and the insert;

a second gasket adapted to locate, in use, between the insert and the exterior of the first pipe; and a clamp adapted to secure the first part of the body to the first pipe and thereby compress the first and second gaskets to form seals to form seals respectively over the end of the first pipe and around the outside of the first pipe.

It will be appreciated that if the first pipe is lined, the first gasket prevents the passage of fluid between the pipe and its lining. Also, the insert protects the integrity of the lining so that if, in use, the fitting is unfastened and the body removed the insert can be left in position to protect the end of the lined pipe and maintain a seal.

Other preferred but non-essential features of the various aspects of the present invention are described in the dependent claims appended hereto.

The present invention will now be described by way of example with reference to the accompanying drawings, in which:Fig. 1 is a side view of a pipe joint seal fitting in accordance with the invention when fitted to a first pipe;

Fig. 2 is a longitudinal section along the line II-II in Fig. 1;

Fig. 3 is a longitudinal sectional of a main body part of the fitting shown in Figs. 1 and 2; and

Fig. 4 is a longitudinal section of an insert forming part of the fitting shown in Figs. 1 and 2.

The drawings show an example of a pipe joint seal fitting 1 for connecting a first pipe 2 to a second pipe or pipe connector (not shown). It is expected that in most instances the fitting 1 will be used to couple a gas supply pipe 2 to a pipe connector forming part of a gas meter at a gas customer’s premises. It will be appreciated that gas meters are fitted at the point where an external supply pipe enters the customer’s premises. Hence the supply pipe 2 will typically be either a lined pipe or a pipe that will subsequently be lined whereas the pipe connector of the gas meter or an internal gas pipe within the premises will be unlined. The fitting 1 has therefore been designed not only to provide a fluid-tight seal between the exterior and interior pipework but also to prevent gas tracking back along the exterior pipe between its lining and the outer pipe.

However, it will be appreciated that the fitting 1 could be used in many other situations where it is necessary to connect a first pipe 2 to a second pipe or pipe connector with a fluid-tight fitting. The first pipe 2 may or may not be lined but typically the second pipe will be unlined. Usually, the first pipe will have a larger diameter than the second pipe. In the drawings, a lining 3 in the first pipe 2 is shown by the dashed lines in Fig. 1. Such a lining will typically be a sprayed-on resinous lining that after curing effectively forms a plastics pipe within the outer pipe 2, which may be a metal pipe. In most cases the lining 3 will be applied to the pipe 2 after the fitting 1 has been fitted but the fitting 1 could be used where the pipe 2 has already been provided with a lining.

The fitting 1 comprises several parts including a main body 4 that defines a passageway 5 and an internal shoulder 6. On opposite sides of the shoulder 6 are first and second parts 7 and 8 of the body 4 respectively. The first part 7 is adapted to fit externally around the first pipe 2 whereas the second part 8 is adapted to be connected to the second pipe or pipe connector. This latter connection will typically be by screwing to a complementary screw thread on the connector or second pipe and usually the second part 8 will be provided with an external screw thread 9 for screwing into the second pipe or connector. Preferably, the exterior of the body 4 comprises an annular radial projection 10 with opposing flats 11 that is situated and projects outwards adjacent the shoulder 6. In the illustrated example, the projection 10 defines a hexagon. In use, after screwing the second part 8 of the body 4 to a second pipe or connector, the screw connection can be tightened by a wrench or similar tool that can grip opposing flats 11 until the end of the second pipe or connector is close to or abuts the radial projection 10.

An insert 12, as shown in Fig. 3, is provided that in use locates between the first part 7 of the body 4 and the exterior of the first pipe 2. The insert 12 is substantially cylindrical but with a flared rim 13 at one end and an internal, annular channel 14 at its other end. In use, as shown in Fig, 2, the end of the first pipe 2 is located within the channel 14 and the annular base 15 of the channel 14 is located adjacent the shoulder 6. The base 15 of the channel thereby protects the edges of the pipe 2 and the lining 3 from damage during fitment, tightening and unfastening of the fitting 1.

In order to provide a fluid-tight seal between the fitting 1 and the pipe 2, a first gasket 16 is located between the shoulder 6 and the insert n and in particular is sandwiched between the shoulder 6 and the base 15 of the channel 14. This gasket 16 is preferably a face seal and is provided to seal the interface between the pipe 2 and its lining 3 at the end of the pipe 2. A second gasket 17 is also provided that is accommodated within the flared rim 16 of the insert 12 that in use is located a short distance along the pipe 2 from its end. The gasket 17 is preferably and O-ring that fits tightly around the pipe 2 and is held in place abutting the flared rim 13. The O-ring 17 forms a seal preventing the leakage of fluid from around the outside of the pipe 2.

The first part 7 of the body 2 defines and exterior screw thread 18 is secured to the first pipe 2 by means of a clamp, preferably in the form of a collet 19 and a nut 20, which screws to the screw thread 18 over the insert 12 and the O-ring 17.

Hence, in use, the fitting 1 is firstly secured to the second pipe or pipe connector as indicated above, the face seal 16 located against the shoulder and then the insert 12 is carefully fitted to the first pipe 2 along with the Oring 17. The fitting 1 is then tightened into position by screwing down the nut 20 over the collet 19. If the pipe 2 is not lined it may be lined thereafter in a conventional fashion, the lining 3 abutting the insert 12. The advantage of the fitting 1 is that if work needs to be carried out and the fitting 1 needs to be slackened or even disconnected from the first 2 and second pipes, the insert 12 can be left in place so that the lining 3 and either or both the gaskets 16, 17 are not disturbed. Alternatively, if the fitting 1 is fitted after the pipe 2 is lined then it protects the edge of the lining 3 at the end of the pipe 2 and, again, if it needs to be disconnected or slackened for subsequent work to be carried out then the insert 12 can be left in position to protect the end of the pipe 2 and its lining 3. It will be appreciated, however, that the fitting 1 is can still be used to sealing a joint between two pipes or between a pipe and a component secured to the pipe regardless of whether either of these pipes is lined.

Claims

1. A pipe joint seal fitting for connecting a first pipe to a second pipe or to a pipe connector comprising a body part defining a passageway therethrough and an internal shoulder such that on one side of the shoulder a first part of the body is adapted to fit externally around an end of the first pipe and on the other side of the shoulder a second part of the body is adapted to be connected to the second pipe;

a first gasket located between the internal shoulder and the insert;

2. A fitting as claimed in Claim 1, wherein the first part of the body defines an external screw thread and the clamp comprises a collet and nut, which screws to said screw thread over the first part of the body.

3. A fitting as claimed in Claim 1 or Claim 2, wherein the first gasket comprises a face seal.

4. A fitting as claimed in any of Claims 1 to 3, wherein the second gasket comprises an O-ring.

5. A fitting as claimed in Claim 4, wherein the insert defines a flared rim that, in use, abuts and accommodates the O-ring.

6. A fitting as claimed in any of Claims 1 to 5, wherein the second part of the body part comprises an external or an internal screw thread that is adapted to be secured to a complementary screw thread defined by

5 the interior or external surface of the second pipe.

7. A fitting as claimed in Claim 6, wherein the second part of the body part comprises an external screw thread.

10

8. A fitting as claimed in any of Claims 1 to 6, wherein the exterior of the body adjacent the shoulder comprises an annular, radial projection defining opposing flats