WO2016139480A2

WO2016139480A2 - Coupling assembly

Info

Publication number: WO2016139480A2
Application number: PCT/GB2016/050559
Authority: WO
Inventors: Paul Nicholas WHITELEY
Original assignee: Pegler Yorkshire Group Limited
Priority date: 2015-03-04
Filing date: 2016-03-03
Publication date: 2016-09-09
Also published as: GB201503673D0; WO2016139480A3; GB201713796D0; GB2551457A

Abstract

The invention relates to a push fit coupling assembly comprising a coupling and a pipe liner, the pipe liner having a head portion and a body, wherein the outer surface of the body comprises at least one formation for securing the pipe liner to the interior surface of a pipe and the assembly comprises a retaining element, which in use secures the liner to the coupling as a lined pipe is pushed into the coupling.

Description

Coupling Assembly

Technical Field of the Invention

The present invention relates to a coupling assembly for coupling a lined pipe. The invention further relates to a method for assembling said coupling assembly. Background to the Invention

Push fit couplings such as those used in plumbing applications are typically designed to couple plastic pipes (also known as tubes). Before inserting the pipe into the coupling, it is typical to line the inside surface of the pipe with a liner, The liner supports the pipe and prevents it from collapsing when the pipe is exposed to high temperatures which could lead to failure of the joint. The lined plastic pipe is then inserted into the coupling and is secured to the coupling by a metal or plastic grab ring or wedge that grips the external surface of the pipe.

Such coupling arrangements suffer from the disadvantage that the grab ring only secures the coupling to the pipe and therefore, if the grab ring fails, it may be possible to push or pull the pipe and the liner from the coupling. The means for holding the grab ring in place can also be complicated

The present invention seeks to provide an improved coupling assembly for securing pipes.

Summary of the Invention

According to a first aspect of the invention there is provided a coupling assembly which comprises a coupling for coupling a pipe and a liner for lining an inside wall of the pipe, wherein the liner comprises a connecting element, wherein in use the pipe and the liner are secured to the coupling via the liner. Securing the pipe to the coupling via the liner can reduce the number of components required and improve the strength of the connection.

The connecting element may connect to an outside surface of the pipe in order to secure the pipe to the liner. This has the benefit that movement of the liner within the pipe may be prevented or at least reduced, which ensures the pipe is sufficiently supported during use.

The connecting element may comprise one or more gripping arms and each gripping arm preferably comprises a lip that is adapted for connecting the liner to the coupling.

The gripping arm may also comprise one or more projections for connecting the liner to the pipe. It has been found that projections comprising v-shaped formations, x- shaped formations or formations in the form of spikes, barbs, ridges, teats, pyramids or arcs are very suitable for connecting and securing the pipe to the liner.

The one or more gripping arms may extend radially outwards from the liner. Preferably the one or more gripping arms extend axially along the length of the pipe. When the lined pipe is inserted into the coupling the walls of the coupling force the gripping arms towards and into contact with the outside surface of the pipe to secure the pipe to the liner.

Each gripping arm may be made of a metal or a metal alloy such as steel. The metal or metal alloy should be flexible enough to allow the gripping arms to be forced towards the outside surface of the pipe as the liner and the pipe are inserted into the coupling. The liner may also be made of a metal or metal alloy such as steel, in which case the gripping arms may be integral to and extend radially outwards from the liner. Alternatively, the connecting element may be in the form of a gripping arm attachment that comprises one or more gripping arms that extend radially outward from a ring member. The gripping arm attachment may be slidably mountable onto the liner and may be secured by suitable securing means. A snap fit thread is particularly suitable for securing the gripping arm attachment to the liner.

The gripping arm attachment may be made of plastics. When the gripping arm attachment comprises plastics, it is preferred that the liner is also made of plastics since this promotes a better connection between the pipe and the liner, Preferably the liner comprises a plastic material that is softer than plastic material of the gripping arm or at least the protrusions of the gripping arm. Again, this promotes the connection between the pipe and the liner.

The coupling may comprise a recess in an inside wall of the coupling and the recess is preferably adapted to receive the lip of the one or more gripping arms. As the liner and the pipe are inserted into the coupling the lip of the gripping arm will snap into the coupling recess to secure the line to the coupling.

The cross-sectional area of the coupling may reduce inwardly from a coupling end adapted to receive the pipe, As the pipe and the liner with the radially outwardly extending gripping arms are inserted into the socket the reduction in cross-sectional area forces the gripping arms towards outer surface of the pipe. As the pipe and the liner are inserted further into the pipe, the walls of the coupling force the protrusions on the gripping arms into contact with the outer surface of the pipe.

The connecting element may alternatively be in the form of a thread formed on an outside surface of the liner. This enables the liner to be screwed into and connect securely to the pipe, The liner may comprise a head section that is adapted to receive a tool so that the liner may be screwed into the pipe. The head section may also have a circumferential area that is greater than the body of the liner. A shoulder may be provided between the thread and the head section. The shoulder prevents the liner being inserted too deeply into the pipe. It also ensures that a recess is formed between the head section and a mouth of the pipe once the liner is inserted into the pipe. The recess thus formed may comprise a connection element and is particularly suitable for receiving a retaining element that may secure the coupling to the liner. The retaining element may be in the form of a snap ring.

According to a second aspect of the invention there is provided a method for coupling a pipe, which comprises the steps of:

- providing a pipe;

- providing a liner comprising a connecting element for connecting the pipe to the liner and for connecting the liner to a coupling;

- connecting the pipe to the liner, and

- connecting the liner to the coupling.

The method according to the second aspect of the invention may be used to assemble the coupling assembly of the first aspect of the invention. The method according to the second aspect of the invention may, as appropriate, incorporate any or all of the features described in relation to the coupling assembly according to the first aspect of the invention.

In a preferred embodiment the method may comprise the steps of:

- providing the coupling, said coupling having a retaining recess for connecting the liner to the coupling; 16 050559

5

- connecting the liner to the coupling;

- sliding the pipe along the liner into a first position within the coupling so that a wall of the coupling forces the connecting element into contact with an outside surface of the pipe, and

- sliding the pipe along the liner into a second position within the coupling so that a connection is formed between the connecting element and the retaining recess to secure the liner to the coupling.

A first seal may be provided between the pipe and the liner. The seal may comprise an O-ring.

In a preferred embodiment the method may comprise the steps of:

- providing the coupling, said coupling having a retaining recess for securing the lined pipe within the coupling;

- inserting the liner into the pipe;

- inserting the lined pipe into a first position within the coupling, thereby forcing the connection element into contact with an outside surface of the pipe, and

- inserting the lined pipe into a second position within the coupling so that a connection is formed between the connecting element and the retaining recess to secure the lined pipe within the coupling.

A first seal may be provided on the liner to form a water tight seal between the liner and the pipe. A second seal may also be provided on the liner to form a water tight seal between the liner and the coupling. Preferably each seal is in the form of an O-ring.

In a preferred embodiment the method may comprise the steps of - providing a liner, wherein the connecting element is in the form of a thread provided on the outside surface of the liner;

- screwing the liner into the pipe such that the outside surface of the liner is connected an inside surface of the pipe;

- inserting the lined pipe into the coupling, and

- securing the lined pipe to the socket of the coupling.

When the liner is inserted into the pipe a recess may be formed between the head section of the liner and the pipe. This recess is particularly suitable for receiving a retaining element such as a snap ring. In use the snap ring snaps into the recess formed between the liner head section and the pipe to secure the coupling to the liner.

According to a third aspect of the invention there is provided a push fit coupling assembly comprising a coupling and a pipe liner, the pipe liner having a head portion and a body, wherein the outer surface of the body comprises at least one formation for securing the pipe liner to the interior surface of a pipe and the assembly comprises a retaining element, which in use secures the liner to the coupling as a lined pipe is pushed into the coupling. The push fit coupling of the third aspect of the invention may, as appropriate, incorporate any or all of the features described in relation to the coupling assembly according to the first aspect of the invention.

According to a fourth aspect of the invention there is provided a push fit coupling assembly comprising a coupling and a pipe liner, the pipe liner having a body and gripping arms depending from the body, wherein the gripping arms comprise formations that face the body, such that in use, the formations are brought into engagement with an outer surface of the pipe as a lined pipe is pushed into the coupling. The push fit coupling of the fourth aspect of the invention may, as appropriate, incorporate any or all of the features described in relation to the coupling assembly according to the first aspect of the invention.

Detailed Description of the Invention In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figures 1A-1B show a lateral cross section view through a coupling assembly according to a first embodiment of the present invention.

Figure 1C is an exploded perspective view of a liner according to the first aspect of the invention.

Figures 2A-2E show lateral cross-section views of the coupling assembly according to a second embodiment of the invention being assembled. Figure 3 is an exploded perspective view of the coupling assembly according to the second embodiment of the invention.

Figure 4 is an exploded perspective of a liner according to the second aspect of the invention.

Figures 5A-I are perspective views of multiple gripping arms that may be used in accordance with the second embodiment of the invention.

Figure 6 shows a perspective view of a liner according to a third embodiment of the invention and a pipe. Figures 7A-7E show lateral cross-section views of the coupling assembly according to a third embodiment of the invention being assembled.

Figure 1 A shows a coupling assembly 1 according to a first embodiment of the invention, A coupling 2 is provided to couple a pipe 3. The coupling 2 in this embodiment is in the form of an annular body having a first mouth 4 and a second mouth 5 provided at opposite ends of the annular body defining a through passage therebetween.

The coupling assembly comprises a liner 6 in the form of a substantially cylindrical body 6a (Figure 1 C). A frustoconical section 7 is provided at one end of the cylindrical body 6a and a plurality of gripping arms 8 are provided circumferentially at an end of the cylindrical body 6a opposite the frustoconical section 7. The gripping arms 8 are integral to the cylindrical body 6a and extend radially outwards and axially in the direction of the frustoconical section 7. The cylindrical body 6a and each gripping arm 8 are made from a metal alloy such as steel, so as to be resilient.

Each gripping arm 8 comprises a substantially rectangular portion 9 and a lip 10 at an end of the gripping arm, The lip 10 is provided at the free end of the rectangular portion 9 away from the liner 6 and is adapted for cooperating with a first recess 11 located in the inside wall of the coupling 2 for securing the liner 6 to the coupling 2. A plurality of projections 12, e.g. spikes, are provided on a surface of the rectangular portion 9 facing the outer surface of the liner 6, to grip the pipe 3,

In addition to the first recess 1 1 located in the inside wall of the coupling 2, which secures the liner to the coupling, a second recess 15 is located axially outwardly of the first recess 1 1. The second recess 15 extends deeper into the coupling. Axially outwardly of the second recess, a seal 13 is located in a groove.

To assemble the coupling assembly 1 the liner 6 is first oriented such that the frustoconical section 7 faces away from the coupling 2. The end of the liner 6 having the gripping arms 8 is then inserted into mouth 4, past the seal 13 and is retained in the coupling 2 via the gripping arms 8 engaging with the second recess 15. As shown in Figure IB (right hand side), a pipe 3 is then pushed over the liner 6, past a seal 13 and into the space between the radially extending gripping arms 8 and the liner. When in the second recess 15, the gripping arms 8 are angled away from the pipe 3 to allow the pipe 3 to reach the end of the liner 6. The wall 14 of the coupling 2 axially inwardly of the recess 15 is angled so that it narrows as the pipe 3 and liner 6 are pushed further into the coupling 2. This causes the gripping arms 8 to fold inwards and the spikes 12 to penetrate the outside surface of the pipe 3, thereby securing the pipe 3 to the liner 6. As the pipe 3 and the liner 6 are pushed further into the coupling 2, the lip 10 snaps into the tapered retaining recess 1 1 provided in the inside wall of the coupling 2 to cooperatively secure the liner 6 to the coupling 2.

Figures 2A-2E show a method for assembling a coupling assembly according to a second embodiment of the invention. As shown in Figure 2A, the liner 106 of the second embodiment has a substantially cylindrical body 106a and is provided with a plurality of radially extending gripping arms 108 at one end of the body 106a. As best shown in Figure 3 and Figure 4, the liner 106 is provided with a gripping arm attachment 1 16 that may be mounted onto the outside surface of the liner 106. The gripping arm attachment 116 is composed of a ring member 117 provided with a plurality of radially extending gripping arms 108 that are spaced around the periphery of the ring member 1 17. As with the gripping arms of the first embodiment, each gripping arm 108 has a substantially rectangular portion 109, a lip 110 and inwardly facing projections 1 12 provided on the rectangular portion. The ring member 1 17 of the gripping arm attachment 116 is held in a first circumferential groove 118 adapted for retaining the gripping arm attachment 116, e.g. by using snap-fit means or adhesives. A first seal 119 in the form of an O-ring is thereafter provided in a second circumferential groove 120 for forming a water tight seal between the liner 106 and the coupling 102. The second circumferential groove 120 is located at an end of the liner 106 away from lips 110 of griping arms 108. Then, a second seal 121 , also in the form of an O-ring, is provided in a third circumferential groove 122 located at end of the liner closest the lips 110 of gripping arms 108 in order to form a water tight seal between the liner 106 and the pipe 103.

As shown in Figure 5A-I, many projection geometries may be used in accordance with the present invention. For example, the projections may comprise V- shaped formations 112a or X-shaped formations 1 12g, The projections may alternatively comprise a plurality of ridges that extend partially 1 12d or fully 1 12b across the width of the rectangular portion 109. Other suitable projection geometries include arc-shaped formations 122e, pyramid-shaped formations 112i, diamond-shaped formations 112f and teat-shaped formations 112h. In use, to couple a pipe, the liner 106 is oriented such that the end of the liner

106 comprising the radially extending gripping arms 108 is facing away from the pipe 103 into which the liner 106 is to be inserted. Then, as shown in Figure 2B, the end of the liner 106 remote from the radially extending gripping arms 108 is inserted into the pipe 103 until the mouth 104 of the pipe abuts the gripping arms 108 of the gripping arm attachment 1 16. Then, as shown in Figure 2C, the end of the lined pipe 103 with the gripping arms 108 is inserted into a coupling 102 having a cross-sectional area greater than the pipe. As the lined pipe 103 is inserted further into the coupling 102 (Figure 2D), the coupling 102 having an inwardly reducing cross-sectional area forces the gripping arms 108 to fold inwards towards the pipe 103 until the gripping arms 108 are parallel to the pipe 103 and the spikes 112c have penetrated the outer surface of the pipe 103 to secure the pipe 103 to the liner 106. Finally, as shown in Figure 2E, the pipe 103 is inserted further into the coupling 102 until the lip 110 of the gripping arm 108 snaps into a retaining recess 1 1 1 present in the inside wall of the coupling 102 to secure the liner 106 to the coupling 102, In this way the liner 106 is secured both to the pipe 103 and to the coupling 102.

Figures 7A-7E show a method for assembling a coupling assembly according to a third embodiment of the invention. Figure 6 shows a liner 206 in the form of a substantially cylindrical body 206a having on its outside surface a helical structure in the form of thread 223. At one end of the cylindrical body 206a is provided a hexagonal head section 224 that is adapted for receiving a tool so that the liner 206 may be screwed into the pipe 203. As best shown in Figures 7A-7E, the outer diameter of the head section 224 is greater than the outer diameter of the cylindrical body 206a. The liner 206 additionally comprises an outwardly protruding shoulder 225 located between the head section 224 and the end of the thread 223 closest the head section 224. As shown in Figure 7A, the liner 206 is screwed into a pipe 203 using a tool having a complementary shape to that of the head section 224. As shown in Figure 7B, the shoulder 225 abuts the mouth 204 of the pipe 203 which prevents the liner 206 from being screwed too deeply into the pipe 203. This also results in a recess 226 being formed between the head section 224 and the mouth 204 of the pipe 203. Once the pipe 203 has been secured to the liner 206 the lined pipe 203 is oriented such that the head section 224 of the liner 206 is facing the coupling 202. Then, as shown in Figure 7C, the lined pipe is inserted axially into the coupling 202. The lined pipe 203 passes through a seal 227, e.g. an O-ring, provided in a circumferential groove 228 within the coupling 202. As the lined pipe 203 passes through the seal 227, the seal 227 is compressed and is forced against the inside wall of the coupling 202 to create a water tight seal between the outside wall of the pipe 203 and the inside wall of the coupling 202. As the lined pipe 203 is inserted further into the coupling 202, the head section 224 meets a retaining element 229 such as a snap ring that is housed within a further circumferential groove 230 in the coupling 202. The front of the head section 224 is tapered so as to centre the snap ring 229 and to cause expansion of the snap ring 229 as the lined pipe 203 is inserted further into the coupling 202 (Figure 7D). Once the widest part of the head section 224 has passed through the snap ring 229 the snap ring contracts into the recess 226 that was formed between the head section 224 and the mouth 204 of the pipe 203, thereby securing the coupling 202 to the liner 206 (Figure 7E). Since the liner 206 is also secured to the pipe 203, this prevents the pipe 203 from being pushed or pulled out of the coupling 202.

The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention.

Claims

1. A push fit coupling assembly comprising a coupling and a pipe liner, the pipe liner having a head portion and a body, wherein the outer surface of the body comprises at least one formation for securing the pipe liner to the interior surface of a pipe and the assembly comprises a retaining element, which in use, secures the liner to the coupling as a lined pipe is pushed into the coupling.

A coupling assembly according to claim 1 or claim 2, wherein the body comprises a thread formed on the outside surface of the pipe liner.

A coupling assembly according to any preceding claim, wherein the lined pipe comprises a recess formed between the pipe liner and the pipe.

A coupling assembly according to any preceding claim, wherein the retaining element is in the form of a snap ring.

A coupling assembly according to claim 3 or claim 4, wherein the retaining element is provided in the recess formed between the pipe liner and the pipe.

A coupling assembly according to any preceding claim, wherein the assembly comprises at least one seal.

A coupling assembly according to claim 6, wherein the seal is arranged to form a seal between an outside wall of the pipe and an inside wall of the coupling.

A coupling assembly according to claim 6 or claim 7, wherein the seal is an O-ring.

9. A push fit coupling assembly comprising a coupling and a pipe liner, the pipe liner having a body and gripping arms depending from the body, wherein the gripping arms comprise formations that face the body, such that in use, the formations are brought into engagement with an outer surface of the pipe as a lined pipe is pushed into the coupling.

10, A coupling assembly according to claim 9, wherein the one or more gripping arms comprise a lip for connecting the pipe liner to the coupling.

11. A coupling assembly according to claim 9 or claim 10, wherein the formations comprise v-shaped formations, x-shaped formations or formations in the form of spikes, barbs, ridges, teats, pyramids or arcs.

12. A coupling assembly according to any one of claims 9-11, wherein one or more gripping arms extend radially outwards from the pipe liner.

13. A coupling assembly according to any one of claims 9-12, wherein the gripping arms are made of a metal or a metal alloy.

14. A coupling assembly according any one of claims 9-12, wherein the pipe liner comprises a gripping arm attachment, said gripping arm attachment comprising gripping arms that extend radially outward from a ring member.

15. A coupling assembly according to claim 14, wherein the gripping arm attachment is slidably mountable onto the pipe liner.

16. A coupling assembly according to claim 14 or 15, wherein the pipe liner and the gripping arm attachment is made of plastics.

17. A coupling assembly according to any one of claims 9-16, wherein the coupling comprises a recess in an inside wall of the coupling, said recess being adapted to receive the lip of one or more gripping arms.

18. A coupling assembly according to any one of claims 9-17, wherein the cross- sectional area of the coupling reduces inwardly from a coupling end adapted for receiving the pipe.

19. A coupling assembly according to any one of claims 9-18, wherein the assembly comprises an O-ring for forming a seal between the pipe and the coupling.

20. A coupling assembly according to any one of claims 9-18, wherem the assembly comprises an O-ring for forming a seal between the pipe liner and the coupling.

21 , A coupling assembly according to any one of claims 9-18, wherein the assembly comprises an O-ring for forming a seal between the pipe liner and the pipe.

22. A method for coupling a pipe, which comprises the steps of:

- providing a pipe;

- providing a pipe liner, comprising connecting elements for connecting the pipe to the pipe liner and for connecting the pipe liner to a push fit coupling;

- connecting the pipe to the pipe liner, and then - pushing the lined pipe into the coupling to connect the pipe liner to the coupling.

23. A method for coupling a pipe according to claim 22, which comprises the steps of:

- providing the push fit coupling, said coupling having a retaining recess for connecting the pipe liner to the coupling;

- connecting the pipe liner to the couplmg;

- sliding the pipe along the pipe liner into a first position within the coupling so that a wall of the coupling forces the connecting element into contact with an outside surface of the pipe, and

- sliding the lined pipe further into the coupling to a second position within the coupling so that a connection is formed between the connecting element and the retaining recess to secure the pipe liner to the coupling.

24. A method for coupling a pipe according to claim 22, which comprises the steps of:

- providing the push fit coupling, said coupling having a retaining recess for securing the lined pipe within the coupling;

- inserting the pipe liner into the pipe;

- inserting the lined pipe into a first position within the coupling, thereby forcing the connection element into contact with an outside surface of the pipe; - inserting the lined pipe further into the coupling into a second position so that a connection is formed between the connecting element and the retaining recess to secure the lined pipe within the coupling.

25. A method for coupling a pipe according to claim 22 or claim 23, wherein the connecting element comprises one or more gripping arms.

26. A method for coupling a pipe according to claim 25, wherein the one or more gripping arms comprise a lip for connecting the pipe liner to the coupling.

27. A method for coupling a pipe assembly according to claim 25 or claim 26, wherein the one or more gripping arms comprise projections for connecting the pipe liner to the pipe,

28. A method for coupling a pipe assembly to any one of claims 25-27, wherein the projections comprise v-shaped formations, x-shaped formations or formations in the form of spikes, barbs, ridges, teats, pyramids or arcs.

29. A method for coupling a pipe according to any one of claims 25-28, wherein the one or more gripping arms connect to an outside surface of the pipe.

30. A method for coupling a pipe according to any one of claims 25-29, wherein the one or more gripping arms extend radially outwards from the pipe liner.

31 , A method for coupling a pipe according to any one of claims 25-29, wherein the pipe liner comprises a gripping arm attachment, said gripping arm attachment comprising one or more gripping arms that extend radially outward from a ring member.

32. A method for coupling a pipe according to claim 31, wherein the gripping arm attachment is slidably mountable onto the pipe liner,

33, A method for coupling a pipe according to any one of claims 25-32, wherein the pipe liner and the gripping arms are made of plastics, a metal or a metal alloy.

34. A method for coupling a pipe according to claim 23, wherein a seal is provided between the pipe and the pipe liner.

35. A method for coupling a pipe according to claim 34, wherein a first seal is provided between the pipe and the pipe liner and a second seal is provided between the pipe liner and the coupling.

36. A method for coupling a pipe according to claim 22, which comprises the steps of:

- providing a pipe liner, wherein the connecting element is in the form of a thread provided on the outside surface of the pipe liner;

- screwing the pipe liner into the pipe such that the outside surface of the pipe liner is connected to an inside surface of the pipe;

- inserting the lined pipe into the coupling, and

- securing the lined pipe to the socket of the coupling.

37. A method for coupling a pipe according to claim 36, wherein the pipe liner is inserted into the pipe to define a recess between a head section of the pipe liner and the pipe.

38. A method for coupling a pipe according to claim 37, wherein a snap ring is provided in the recess formed between the pipe liner and the pipe to secure the coupling to the pipe liner,

39. A coupling assembly or a method of coupling pipes substantially as described herein with reference to the accompanying drawings.