GB2503880A

GB2503880A - Insert for Pipes

Info

Publication number: GB2503880A
Application number: GB1212166.1A
Authority: GB
Inventors: Keith Millward; John Lang
Original assignee: Polypipe Ltd
Current assignee: Polypipe Ltd
Priority date: 2012-07-09
Filing date: 2012-07-09
Publication date: 2014-01-15
Anticipated expiration: 2032-07-09
Also published as: GB2503880B; GB201212166D0

Abstract

An insert for the free end of a pipe. The insert comprises a body having first and second ends, and defining a fluid flow path between the first and second ends. The first end of the insert is configured for insertion into the free end of a pipe, and is further configured for providing a seal between the insert and the inside of the pipe in the absence of fluid flowing through the pipe. The second end of the insert is configured to project from the free end of the pipe when the first end of the insert is in sealing communication with the inside of the pipe, and is further configured for providing a seal against part of a pipe connector in the absence of fluid flowing through the pipe. The insert is configured for modifying the effective sealing action of the second end under activation from fluid flowing through the insert under pressure.

Description

Insert for pipes

Field of Invention

The present invention relates to an insert for use with pipes, e.g. an insert of the kind intended to be positioned in the free end of a pipe, for use in stiffening the free end of the pipe and/or for providing a seal when the free end of the pipe is located inside a socket on a pipe connector or the like.

Background

Inserts for use in stiffening the free end of a pipe are known. Such known inserts typically define an elongate body, wherein one end of the body is configured to be positioned in the free end of a pipe and the other end of the body has a lip, flange or other formation intended to limit the extent of insertion of the body into the pipe.

Figure 1 shows a known arrangement of pipe connector 1010, plastics pipe 1012 and plastics pipe insert 1014. The arrangement is shown in exploded form to the left as viewed in Figure 1 and in assembled form to the right as viewed in Figure 1.

In this instance, the pipe connector 1010 defines an elongate body 1016 having opposing sockets 1018, 1020. Each socket 1018, 1020 is configured for receiving the free end of a pipe 1012 and includes a collet 1024 (mounted on the fitting by means of a cap 1022) for gripping the pipe 1012 in a manner known in the art. The pipe insert 1014 is located in the free end of the pipe 1012 prior to insertion into one of the sockets 1018, 1020, and serves to stiffen the free end of the pipe 1012. In order to provide a seal between the pipe 1012 and the connector 1010, an 0-ring 1026 is positioned between two washers 1028 inside each socket 1018, 1020. The 0-ring 1026 acts between an external surface of the pipe 1012 and an internal surface 1019 of the respective socket 1018, 1020, to prevent leakage from the connector 1010.

Figure 2 illustrates another known arrangement, which uses a grab ring 2032 instead of a collet 1024. Other features are similar, and so will not be described further here.

I

Similar features are given similar reference numerals as the features of Figure 1, but with a prefix of 2 instead of 1.

The grab ring 2032 is arranged between two washers 2030, 2031 and includes a plurality of teeth (not shown) for gripping the pipe 2012 in a manner known in the art.

Again, the pipe insert 2014 is of plastics construction, but in alternative examples may be of stainless steel construction, and serves to stiffen the free end of the pipe 2012.

and an 0-ring 2026 within the connector 2010 provides a seal between an external surface of the pipe 2012 and an internal surface 2019 of the respective socket 2018, 2020.

A further known arrangement is described in GB2469640A (as shown in Figure 3 herein), wherein the pipe insert 3014 is of stainless steel construction. In this instance, 0-rings 3034, 3036 are mounted on the insert 3014. In particular, a first 0-nng 3034 provides a seal between the insert 3014 and the inside of the pipe 3012, and a second 0-ring 3036 provides a seal between the insert 3014 and an internal surface 3021 within the connector 3010. As such, the insert 3014 provides a sealing function in addition to a conventional stiffening function, and so is sometimes referred to as a sealed stiffener. Alternative sealed stiffeners similar to the type described in 0B2469640A may be of plastics construction.

Advantageously, even if the outside of the pipe is scored prior to installation (e.g. as a result of being dragging along a floor) resulting in leakage between the pipe and the socket, the insert maintains a seal between the insert and the pipe (since the inside of the pipe is unlikely to be affected by the scoring on the outside of the pipe).

Problems may occur if sealed stiffeners are used with pipe connectors of plastics construction. In particular, the sealing effect of the 0-ring 3036 with the internal surface 3021 of the socket 3020 may be affected by the temperature or pressure of fluid passing through the connector. For example, if a plastics socket is subjected to high temperatures and/or pressures for long periods of time, the socket material may experience creep effects, which can lead to changes in the internal configuration of the socket, thereby reducing the sealing performance between the stiffener and the internal surface of the socket against which the 0-ring is intended to act. This can result in leakage from the connector.

The problems may be exacerbated if the stiffener is used with a metal composite pipe MCP), e.g. of the kind having outer and inner layers of plastics material and a metal central layer (generally Aluminium), since loss of sealing performance may lead to the end of the pipe becoming exposed to fluid flow. This is problematic because contact with the fluid can cause corrosion of the metal layer. Moreover, the fluid may cause delamination of the inner and outer plastics layer away from the central metal layer.

Delamination can result in blistering of the inner and outer layers. In some cases pressure failure of the pipe can occur because the relatively thin outer plastics ayer is subject to the full or near full pressure of the fluid flow within the pipe without the reinforcing effect of the central metal layer and the inner plastics layer.

Attempts have been made to overcome this problem by using a connector of a different configuration to that shown in Figures I to 3. Such a connector is illustrated generally at 4010 in Figure 4. The connector 4010 has at least one spigot 4034 with a plurality of barbs 4036 formed on the outer surface thereof. Two 0-ring seals 4026 are positioned on the spigot 4034 and a stainless steel sleeve 4038 is arranged about the spigot 4034 -initially spaced from the spigot 4034. To attach a pipe to the connector 4010, the pipe is fitted onto the spigot 4034 and the sleeve 4038 is then deformed into an interference fit with the outside of the pipe using a pressing tool.

This forces the inside of the pipe into close contact with the 0-ring seal 4026 on the spigot 4034 to create a seal, and the barbs 4036 on the spigot 4034 provide axial restraint against the pull-out forces generated by internal hydraulic pressure when the connector 4010 is in use. It can be seen that the connector 4010 seals against the inside of the pipe. and so fluid cannot come into contact with the end of the pipe (overcoming the potential for corrosion or delamination at the exposed end of an MCP).

1-lowever, a problem with this design of connector is that it requires additional equipment to attach a pipe to the connector, instead of a simple push-fit operation that is possible using the connectors shown in Figures 1 and 2.

Summary of the invention

There is a need to address one or more of the above-mentioned problems.

According to a first aspect the present invention there is provided an insert as set forth in claim 1.

The pressure activation at the second end of the insert improves the sealing effect between the insert and the connector. Advantageously, this may limit the nsk of fluid contact with an end of a pipe into which the insert is fitted. This is particularly impor ant when the pipe is a metal composite pipe (N'ICP), since this can alleviate problems of corrosion of the metal layer and delamination of the other layers of the pipe.

In exemplary embodiments, the second end is configured for increasing its effective sealing diameter (e.g. by increasing the radial extent of a sealing part of the second end) under pressure activation of fluid flowing to or through the connector via the insert. This enables the insert to maintain sealing contact between the insert and the pipe connector if the connector expands due to temperature increase, pressure increase andlor creep effects. For MCP applications, this further helps to protect the end of the pipe against fluid contact.

Description of drawings

Other aspects and features of the invention will be apparent from the appended claims and the following description of embodiments, made by way of example, with reference to the accompanying drawings, in which: Figure i shows a sectional exploded and assembled view of a pipe connector assembly of the prior art incorporating a collet for gripping a pipe received in the connector; Figure 2 shows a sectional exploded and assembled view of another pipe connector assembly of the prior art incorporating a grab ring for gripping a pipe received in the connector; Figure 3 is a sectional assembled view of another pipe connector assembly of the prior art, incorporating a seakd pipe stiffener; Figure 4 is a sectional view of a further pipe connector assembly of the prior art, wherein the connector is a press fitting having a deformable sleeve for retaining the pipe on a spigot of the fitting; Figure 5 is a sectional view of a connector and pipe insert according to an embodiment of the invention; Figure 6 is a sectional view of a connector and pipe insert according to another embodiment of the invention; Figure 7 shows a sectional and plan view of a pipe insert according to an embodiment of the invention; Figure 8 shows a sectional and plan view of a pipe insert according to another embodiment of the invention; Figure 9 is a schematic sectional view of a portion of a pipe connector assembly incorporating a pipe insert according to a further embodiment of the invention; figure 10 shows schematically a sectional and plan view of a portion of a pipe insert according to another embodiment of the invention; Figure 11 shows schematically a sectional view of a portion of three pipe inserts according to further embodiments of the invention; Figure 12 is a sectional view of pipe connector assembly incorporating a pipe insert according to another embodiment of the invention; Figure 13 is a sectiona' view of a pipe connector assembly incorporating a pipe insert according to a further embodiment of the invention; and Figure 14 is a sectional view of a pipe insert according to a modified embodiment of the invention.

Detailed description

Referring to Figure 5, a pipe connector is indicated generally at lOa, The pipe connector iOa is similar to the kind shown in Figure 1. As such, it defines a body 16a having first and second sockets 18a. 20a. each configured for receiving the free end of a pipe 12a. A channel ha extends between the first and second sockets 18a, 20a, e.g. for permitting fluid to pass through the body 16a from one pipe 12a to another. k this embodiment the connector body 16a is made from polybutylene. However, in alternative embodiments the connector body may be made from other suitable plastics (such as acetal or polysulphone) or metals such as brass, DZR brass or stainless steel.

In this embodiment, the sockets 18a, 20a are of identical configuration. However, for ease of illustration, only the internal structure of the socket 18a as defined by body 16a of the connector lOa is shown to the right as viewed in FigureS. whereas the full detail of socket 20a is shown to the left as viewed in Figure 5.

Socket 20a includes a cap 22a which serves to locate a conventional collet 24a on the connector lOa. The collet 24a is used for gripping the outer surface of a pipe 12a in a manner known in the art. The cap 22a is mounted on an annular end part 40a of the body 16a (e.g. by snap-fit or threaded engagement). The end part 40a defines a first chamber 42a within the respective socket I 8a, 20a. The first chamber 42a includes an IS annular internal surface 44a. Axially inwardly of the first chamber 42a (e.g. to the left when viewing socket ISa in figure 5), the body 16a defines a second chamber 46a within the respective socket 18a, 20a. The second chamber 46a includes an annular internal surface 48a. which terminates at a stop surface 49a adjacent the channel i la.

In use, a free end of the pipe 12a is inserted into the socket 20a. The free end of the pipe i2a passes through the collet 24a, through the first chamber 42a and into the second chamber 46a, as illustrated to the left as viewed in Figure 5.

An 0-ring 26a is alTanged between two washers 28a within the first chamber 42a of the socket 20a. for providing a seal between the pipe l2a and the internal surface 44a of the socket 20a, for preventing fluid leakage between the pipe 12a and the connector lOa. As can be seen, the 0-ring 26a is axially spaced from the free end of the pipe 12a, when the pipe 12a is inserted in the manner illustrated in figure 5.

A pipe insert 14a is fitted into the free end of the pipe i2a before the pipe i2a is inserted into one of the sockets ISa, 20a on the connector IOa. The insert 14a has a body 50a which defines a bore for the flow of fluid axially through the insert. The body SOa is configured such that, when assembled with a pipe 12a (e.g. as shown in Figure 5), a first end of the insert SOa is positioned within the pipe 12a, and a second end of the insert 14a is arranged outside of the pipe 12a. When the pipe 12a and insert 14a are correctly fitted into the connector lOa, the second end of the insert 14a is located inside the second chamber 46a and abuts the stop surface 49a within the connector body I 6a.

In the embodiment of Figure 5. an 0-ring 64a is provided adjacent the first end of the insert 14a, within a circumferential recess 62a on the balTel of the body SOa. k use, the 0-ring 64a is intended to engage an inner surface of the pipe 12a into which the insert has been fitted, for providing a seal between the insert 14a and the pipe 12a prior to the appfication of fluid through the pipe 12a.

The first end of the body SOa includes a taper 66a at its tip, for easing insertion of the insert 14a into the free end of a pipe 12a.

It may be necessary to provide an internal chamfer at the free end of the pipe I 2a, to provide a lead-in for the 0-ring 64a, to prevent it becoming dislodged during insertion into the pipe 12a.

In the embodiment of Figure 5, the second end of the insert 14a is defined by an enlarged head 52a having a greater outer diameter than the first end of the insert l4a.

The head 52a defines a step 54a. which serves to limit the extent of insertion of the insert 14a into the pipe 12a. e.g. by abutment with a free end of the pipe 12a. An end surface 56a of the head 52a is orthogonal to the axis of the insert bore and is intended for abutting the stop 49a within the connector iDa.

Two projections 58a (orthogonal to the axis of the insert bore) define a recess 59a for locating an 0-ring 60a on the head 52a. One of the projections 58a is immediately adjacent the end surface 56a of the head portion 52a and defines part of the end surface 56a. The other projection 58a is axially spaced from the step 54a. As illustrated in Figure 5. the projections have generally the same external diameter as the external diameter of the pipe 12a into which the insert 14a is to be fitted, whereas the 0-ring 60a (considering the dimensions in a non-assembled state) extends radially beyond the projections 58a.

The 0-ring 60a is intended to engage the internal surface 48a in the second chamber 46a of the socket 20a, for providing a seal between the insert 14a and the connector 1 6a when the free end of the pipe I 2a has been correctly located inside the socket 20a.

prior to the application of fluid through the connector lOa or pipe 12a.

In this embodiment, the insert 14a is specifically configured so that, in use, as fluid flows along the pipe 12a, through the insert l4a and into the connector body 16a (or vice versa) under normal working pressure, the first end of the insert i4a will expand radially, such that the 0-ring 64a is urged into greater engagement with the internal wall of the pipe l2a. Moreover, the second end of the insert l4a is configured to expand radially, such that the 0-ring 60a is urged into greater engagement with the internal surface 48a of the connector body 16a.

Hence, this embodiment of insert is specifically configured for providing a seal with the pipe and the connector in the absence of fluid flowing through the pipe/insert/connector, and for modifying the effective sealing action of the sealing parts (i.e. the 0-ring seals 60a, 64a) when fluid is flowing through the insert under normal working pressure. This may be achieved as a function of the relative flexibility of insert and/or the dimensions/configuration of the insert, and represents a significant improvement on known sealed stiffeners, e.g. of the kind described in GB2469640A (which provide substantially the same sealing action against the pipe and connector under zero flow and normal working pressure conditions). For example, the stiffener (or the part of the stiffener intended to provide a seas with the internal wall of the connector) may be made from a material which is more flexible than the material used to produce the internal wall of the connector, so that the stiffener will deform to a greater extent than the connector body under working pressure, in order to maintain a seal with the connector. In another embodiment, the stiffener (or the part of the stiffener intended to provide a seal with the internal wall of the connector) may be produced from a material which has the same or greater stiffness than the matenal used to produce the internal wall of the connector, but wherein the configuration of the insert means that it will deform to a greater extent than the connector body under working pressure, in order to maintain a seal with the connector (e.g. by reducing the wall thickness of the insert).

The increased sealing action of the sealing parts of the insert 14a (i.e. the 0-ring seals 60a, 64a) against the pipe I 2a and the connector body I 6a serves to prevent fluid from contacting the end of the pipe 12a (which will be a site-cut end in most cases). Hence, when an MCP is used, the risk of corrosion and/or delamination at the free end of the pipe is significantly reduced.

The insert 14a is specifically configured for maintaining a seal between the second end of the insert 14a and the annular internal surface 48a of the second chamber 46a of the connector body 16a in the event that the socket expands as a result of high pressure and/or high temperature effects during use.

This may be achieved by producing the insert (or at least the second end of the insert) from a material that is of greater flexibility under high pressure and/or temperature effects than the material used to produce the connector, for example. Put another way, at least the second end of the insert is preferably of more deformable construction than the second chamber 46a within which the second end of the insert is intended to provide a seal, so that if the second chamber of the connector body expands under the effects of high pressure and/or high temperature during use (i.e. causing the diameter of the annular internal surface 48a to increase), the second end of the insert will deform by a greater extent in order to maintain its seal with the socket (e.g. by increasing the effective external diameter of the second end, and thereby maintaining the 0-ring 60a in sealing contact with the surface 48a). This may also be achieved as function of the dimensions and/or configuration of the second end of the insert 14a.

In exemplary embodiments, the insert 14a is made from plastics material. The insert may be manufactured from polybutylene or PEX for hot water applications, or polyethylene or polypropylene for cold water applications, for example.

In alternative embodiments, the insert may be manufactured from a thermoplastic elastomer, rubber or soft plastics material, for example. In such embodiments, a seal may be formed on an outer surface of the main body andlor the head to seal the insert against an inner surface of the pipe and/or connector. The seal may be a semi-circular or otherwise arcuate radial projection from the surface of the insert.

In further alternative embodiments, the insert may be of composite structure, e.g. one or more sections of the insert are made from a material that is more flexible than the material of one or more other sections of the insert. In such embodiments, the head will typically be made from the more flexible material than the first end of the insert.

The composite insert may be manufactured using methods such as twin shot moulding (or co-moulding/over-moulding), welding, bonding or any other suitable process.

Referring to Figure 6 a further embodiment of the invention is shown. Similar features to those shown in Figure 5 are given a similar reference numeral but with a suffix "b" instead of "a". Similar features operate in a similar way, so mostly only the IS differences between the embodiment shown in Figure 5 and the embodiment shown in figure 6 will be described here.

The head 52b has a step 54b and a side wall 68b or tapered section which extends between the step 54b and the end surface 56b of the head 52b. wherein the outer diameter of the head 52b increases and the wall thickness decreases between the step 54b and the end surface 56b. In a relaxed state, the outer diameter of the head 52b at the end surface 56b is greater than the diameter of the annular surface 48b within the connector body I 6b and greater than the diameter of the pipe I 2b. The outer diameter of the head 52b immediately adjacent the step 54b is in fact less than the diameter of the pipe 12b.

In use, the head 52b is configured to provide an interference fit with the annular surface 48b before pressure is applied (i.e. before fluid is allowed to flow through the pipe); during use, the pressure of the flow within the pipe serves to enhance the sealing effect by deforming the thin taper at the end of the head. The tapered side wall eliminates the need for an 0-ring around the head.

A tool may be required fit the insert in the connector, or the insert can be fitted into the socket before the other components are assembled. hi this case, the pipe would be pushed into the socket to engage onto the first end of the insert as the pipe is fully inserted into the socket.

In this embodiment, at least the head of the insert may be made from polybutylene, PEX, PERT, thermoplastic dastomer or rubber, for example.

Further embodiments of a pipe insert that may be used in a connector of the type previously described are shown in Figures 7 and 8. Again, only differences between the inserts are described again here, and a suffix "c" and "d" is used to distinguish between the different embodiments.

The insert 14c shown in Figure 7 is similar to the insert of Figure 5, but there is only one radial projection 58c around the head. Adding radia' projections stiffens the head, so having only a single projection provides a more flexible head portion compared to the insert of Figure 5. The disadvantage of this arrangement is that the seal on the head could be displaced if the pipe and insert are pulled out of the socket.

The insert l4d shown in Figure 8 is similar to the insert of Figure 5 but the end radial projection 58d is castellated, i.e. the radial projection 58d around the head portion 52d and positioned adjacent the end surface 56d has a series of cut-out' sections 70d (only one cut-out' section is labefled for clarity). In this embodiment there are 8 cut-out sections. This configuration of castellated insert 14d has a more flexible head portion 52d than the insert 14a of Figure 5. but still has a channel to retain an 0-ring seal in substantially the same lateral position when the insert 14d is fitted in or removed from the connector lOd.

Figure 9 shows a modification to a conventional sealed pipe stiffener of the kind described with reference to Figure 3. Again, only differences between the insert of Figure 9 and previously described inserts will be described here, and a suffix "e" is used to distinguish between the embodiments.

In this embodiment, the diameter of the head 52e is substantially constant along its length. However, a curved transition 74e is provided between the side wall 68e and the end surface 66e, to ease insertion of the insert into the connector. The outer diameter of the side wall (except when part of the transition 74e) is substantially equal to the outer diameter of the pipe I 2e into which the insert is to befitted.

A channel 59e is formed around the head 52e into which an 0-ring 60e is positioned.

The channel depth is selected so that the 0-ring 60e projects radially from the channel 59e, for compressive, sealing engagement with the annular surface 48e of the second chamber of the connector body 16e. Importantly, the channel width is selected to axially compress the 0-ring 60e and create a seal with the channel 59e.

The insert may be manufactured from the materials explained with respect to previously described embodiments, or the insert 14e may be manufactured from polysulphone, staiffless sted (pressed) or brass (machined).

A series of radial holes 72e extend from the bore of the insert to the channel 59e. In this embodiment there are four holes, but in alternative embodiments there may be one, two or any suitable number of radial holes.

I

In use, an initial seal is provided between the 0-ring 60e and the second chamber 46e of the connector body 16e, as described above. lii addition, some of the fluid flowing through the pipe 12e will enter the radial h&es 72e and push against the 0-ring 60e.

This serves to increase the sealing action between the 0-nng 60e and the connector Iôe and can account for radial expansion of the annular surface 48e of the connector.

Referring to Figure 10, the insert shown in Figure 9 can be modified to include one or more axial grooves 74f extending from the end surface 56f of the insert 14f to intersect the seal channel 59f, and thereby define a passageway for fluid to act against the 0-ring. The grooves are easier to manufacture than the radial holes 72e from Figure 9. For example, if the insert is moulded. the grooves mean there is no need to use core pins to form the radial holes.

Figure 11 is a partial section of a plurality of different inserts 14g, 14h, 14i, similar to those of Figures 9 and 10, but wherein the 0-ring channel is profiled to improve the pressure activation effects on the 0-ring 60g, 60h, 60i. The proffles shown reduce the risk of the 0-ring sealing off the fluid passageway, so that the pressure transferred by the fluid can be transmitted circumferentially around the 0-ring. For example, the channel 59g may have a trapezoidal base, the channel 59h may be V-shaped, or the channel 59i maybe stepped.

Figure 12 shows a further embodiment of an insert. Again, only the differences will be described here, and a suffix "k" is used to identify features of the embodiment shown in Eiure 12.

The head 52k has an outer diameter slightly larger than the outer diameter of the pipe 12k into which it is fitted, such that the head compresses to create a seal with the inner surface 48k of the second chamber 46k of the connector body I 6k in the absence of fluid flow. In alternative embodiments, the head may have an outer diameter equal to that of a pipe into which the insert is fitted.

Circumferential ribs 78k are positioned around the barrel of the insert 14k. These are dimensioned to provide an interference fit with the inner surface of the pipe 12k, and so form a seal between the insert and the inside of the pipe in the absence of fluid flow. In this embodiment there are three circumferential ribs but in alternative embodiments there may be any appropriate number of ribs.

In this embodiment the insert 14k is made from rubber, but it may also be made from a suitable thermoplastic elastomer or soft plastics material. As such, the integral head 52k forms a seal with the end face of the MCP 12k, providing a watertight seal to prevent fluid within the pipeline from contacting the metal layer within the pipe wall.

In use, the pressure of fluid flowing through the pipe 12k and connector 10k causes the insert to expand radially, mairfly as a resuli of the material it is manufactured from.

The expansion of the insert 14k pushes the main body 50k against the inner surface of the pipe 12k and the head 52k against the inner surface of the connector 10k. The pressure acting on the radial end face of the insert would cause a resultant increase in the radial sealing force acting on the inside diameter of the connector and this sealing force would increase as the pressure increased. Such action improves the seal between the insert and the pipe/connector, which protects the end of the pipe from exposure to fluid flow in the pipe.

Other embodiments are shown in Figures 13 and 14. Only the differences between these embodiments and the embodiment shown in Figure 12 will be described, and a suffix "1" and "m" is used respectively to indicate the features of the embodiments of Figures 13 and 14.

The inserts 141, 14m include a lip 801, 8Dm around the head portion 521, 52m. The lip is formed at an angle to the axis of the bore and so defines an undercut 811, Sim. In Figure 13, the head 521 is shown in a non-compressed state at the lower part of the Figure and in a compressed state, as would be seen in operation, in the upper part of the Figure. An increased seal is created by fluid pressure activation, as described for the embodiment of Figure 12.

In the embodiment of Figure 14, a V-shaped cut-out 82m is provided in the end surface 56m, to permit the lip 80m to be readily displaced inwardly, but also to allow fluid in the pipeline to act inside the cut-out, and thereby cause the outermost limb of the V to move outwards and enhance the sealing effect (e.g. when compared with the embodiment of Figure 13).

The lip 801. 8Dm and V-shaped section 82m permit the inserts 141. 14m to be more easily inserted into the connector 101, lOm compared to the insert 14k of the Figure 12.

In alternative embodiments, inserts similar to the inserts 14k, 141, 14m shown in Figures 12, 13 and 14 may comprise a rigid portion (e.g. of stainless steel) connected to the barrel of the insert, to act as a pipe stiffener. The two parts of dissimilar matenal may be connected by welding, bonding, co-moulding, over-moulding or any other suitable process.

It will be understood that the connectors shown in the accompanying drawings may include a coilet or grab ring arrangement for the gripping the outside of the pipes into which the insets are fitted.

The connectors may take the form of any suitable shape of fitting intended to sealingly receive the free end of a pipe. This will include dbow and T-sections, radiator va'ves and socket blank ends. The fitting need not necessarily be of a kind susceptible to changes in socket configuration as a result of high pressure/temperature in use, but may take the form of a conventional brass, copper or stainless steel fitting, such as a radiator valves for example, where the sealing of the insert can be advantageously used to prevent water from contact with the end of an MCP as water flows to or through the fitting. The fitting may be configured with one, two or more sockets.

Typically, the inserts will be used in plumbing systems and the like, of the kind having pipes for conveying a water supply and requiring an insert to assist connection of the pipe to a fitting within the plumbing system and/or to provide protection for a multilayered pipe within the system. In exemplary embodiments, the inserts will be configured for use in central heating systems. In other embodiments, the inserts will be configured for use in other water supply applications, including indoor and outdoor applications (domestic and/or commercial).

Several of the embodiments described herein include a circumferential seal (e.g. an 0-ring) which is urged in a radial direction under activation of fluid flow under normal working pressure through the insert/pipe/connector. e.g. by directing fluid to act directly against the circumferential seal. It will be understood that similar principles may be applied to a seal provided on the first end of the insert, for urging the seal in a radial direction to increase the sealing action with the inside of the pipe into which the inset is fitted, This principle may be included in rigid embodiments (e.g. in which the insert is manufactured from polysulphone. stainless steel or brass) or embodiments of the kind described herein in which one or more of the sealing parts of the insert are of relatively flexible configuration (i.e. for radial deformation to maintain a seal under

Claims

Claims 1. An insert for the free end of a pipe, the insert comprising: a body having first and second ends, and defining a fluid flow path between the first and second ends, wherein the first end of the insert is configured for insertion into the free end of a pipe, and is further configured for providing a seal between the insert and the inside of the pipe in the absence of fluid flowing through the pipe, wherein the second end of the insert is configured to project from the free end of the pipe when the first end of the insert is in sealing communication with the inside of the pipe. and is further configured for providing a seal against part of a pipe connector in the absence of fluid flowing through the pipe, and wherein the insert is configured for modifying the effective sealing action of the second end under activation from fluid flowing through the insert under pressure.
2. The insert according to claim I wherein the second end is configured for increasing in effective sealing diameter under pressure activation of fluid flowing to or through the connector via the insert.
3. The insert according to claim 1 or claim 2 wherein the second end comprises a sealing portion intended for providing a seal with an internal surface of a pipe connector, and wherein the sealing portion is less rigid in construction or configuration than a part of the connector comprising said internal surface, to enable the sealing portion of the insert to deform to a greater extent under pressure activation of fluid flowing through the insert than the part of the connector comprising said internal surface.
4. The insert according to any of claims I to 3 wherein the second end is produced from a material that enables a sealing portion of the second end to deform radially outwardly under fluid pressure activation.
5. The insert according to any of claims 1 to 4 wherein the second end has a geometry or shape that enables a sealing portion of the second end to increase in effective sealing diameter under fluid pressure activation.
6. The insert according to claim 4 or claim 5 wherein the first end comprises a rigid portion and the second end comprises a relatively flexible portion configured to expand radia'ly under fluid pressure activation.
7. The insert according to any preceding claim wherein a seal element is mounted on the second end for providing a seal with an internal surface of the connector in the absence of fluid pressure, and wherein the second end is configured to deform under normal working fluid pressure for urging the seal element in a radial direction towards said internal surface.
8. The insert according to claim 7 wherein the seal element is an 0-ring or a circumferential seal element mounted in a channel or recess on the second end of the insert.
9. The inser according to any of claims I to 6 wherein the second end indudes a wall for providing an interference fit with an internal surface of the connector in the absence of fluid pressure, and wherein the wall is of a construction configured to deform in a radial direction towards said internal surface under normal working fluid pressure.
10. The insert according to claim 9 wherein the wall has a radial thickness which tapers away towards a distal end of the insert.
11. The insert according to any preceding claim wherein the second end defines an enlarged head on the insert, and wherein the head defines a step for abutment with the free end of a pipe when the first end of the insert is fitted inside the pipe.
12. The insert according to claim 11 wherein the head includes a wall having a distal end intended for interference engagement with an internal surface of the connector.
13. The insert according to claim 12 wherein the wall has a first diameter at the distal end of the head and a second diameter, less than the first diameter, at an opposite end of the head.
14. The insert according to claim 13 wherein the first diameter is configured to be greater than the diameter of pipe into which the insert is intended to be fitted, and wherein the second diameter is configured to be smaller than the diameter of pipe into which the insert is intended to be fitted.
15. The insert according to any of claims I to 11 wherein the second end comprises projections which define a channel or recess into which a circumferential seal element is located.
16. The insert according to daim 15 wherein at least one of said projections defines at least part of an end surface of the insert.
17. The insert according to claim 16 wherein said at least one projection is castellated or comprises a series of cut out sections.I
18. The insert according to any of claims I to Ii or 15 to 17 wherein a circumferential seal is located on the second end and a flow path is provided for directing fluid against at east a portion of the seal to urge the seal outwardly in a radial direction.
19. The insert according to claim 18 wherein the seal is located in a channel or recess on the second end, and the flow path directs fluid from the fluid passageway into the channel for urging the seal in said radial direction.
20. The insert according to claim 18 wherein the seal is located in a channel or recess on the second end, and the flow path directs fluid through grooves formed in a distal end of the insert into the channel for urging the seal in said radial direction.
21. The insert according to claim 19 or claim 20 wherein the seal is axially compressed within the channel prior to activation of the seal from fluid pressure within the flowpath.
22. The insert according to any of claims 19 to 21 wherein the channel has a cross section which is trapezoidal, V-shaped, or stepped.
23. The insert according to any of c'aims 15 to 22 wherein the seal is an 0-ring.
24. The insert according to any of claims 18 to 23 wherein the second end has a side wall with an outer diameter configured to be less than the outer diameter of a pipe into which the insert is intended to be fitted.
25. The insert according to any preceding claim wherein the first end defines a band of the insert and a circumferential seal is mounted in a channel or recess formed on the barrel, for sealing engagement with the inside of a pipe into which the first end is fitted.
26. The insert according to claim 25 wherein a flow path is provided for directing fluid against the seal to urge the seal in a radial direction.
27. The insert according to any of claims I to 4 wherein the second end comprises a thermoplastic elastomer or rubber material.
28. The insert according to claim 27 wherein the second end defines an enlarged head on the insert, configured to forms a seal with the end face of a pipe into which the first end of the insert is fitted.
29. The insert according to claim 27 or claim 28 wherein the second end comprises different material to the first end.
30. The insert according to claim 29 wherein the first and second ends are co-moulded, over-moulded, welded or bonded together.
31. The insert according to any of claims 27 to 30 wherein the first end comprises one or more protrusions for gripping and adding seal to the inside of a pipe into which the insert is intended to be fitted.
32. The insert according to any of claims 27 to 31 wherein the insert is produced from a thermoplastic elastomer or rubber material, and is configured to expand radially under activation of fluid flowing through the insert under normal working pressure.
33. The insert according to any of claims 27 to 32 wherein the second end includes a lip for providing a seal with a connector into which the insert is fitted in the absence of fluid pressure.
34. The insert according to claim 33 wherein second end of the insert is configured for modifying the sealing action of the lip under activation of normal working fluid pressure.
35. The insert according to claim 34 wherein an end face of the second end comprises a groove, notch or cut-out into which fluid can act to cause the lip to move outwards and enhance the sealing effect under normal working pressure.
36. The insert according to any preceding claim wherein the insert is configured for use as a pipe stiffener.
37. A pipe connector assembly comprising a pipe connector having a socket for receiving a free end of a pipe, and a pipe retainer for holding a pipe inserted into the socket; and an insert according to any preceding claim.
38. The pipe connector assemNy according to daim 37. wherein the pipe retainer is a collet or grab ring.
39. The pipe connector assembly according to claim 37, wherein the connector is a compression fitting and the pipe retainer is a sleeve intended to be deformed for holding the pipe in the fitting.
40. The pipe connector assembly according to claim 37 wherein the insert is provided inside the socket prior to insertion of the pipe into the socket.
41. A kit of parts for a pipe connector assembly compnsing: a pipe connector having a socket for receiving a free end of a pipe, and a pipe retainer for holding a pipe inserted into the socket; and an insert according to any preceding claim.
42. The kit of parts according to claim 41, further comprising an MCP, or a pipe made from polybutylene, PEX or PERT.
43. An insert substantially as hereinbefore described with reference to andlor as shown in any one of Figures 5 to 14.