A pipe connector for connecting pipes of different materials

Abstract

A pipe connector for mechanically connecting two pipes made of different materials is disclosed. The connector may comprise an inner member made of a first material that comprises a conduit section having a shoulder extending radially outward therefrom, and a surround member made of a second material that is different to the first material. The surround member may comprise a further conduit section and a locking section extending axially away from the conduit section. The locking section may be configured to extend behind at least part of the shoulder and resist movement of the surround member in an axial direction away from the inner member. This mechanically connects or attaches the inner member and surround member to each other. A pipeline installation including the connector is also disclosed.

Description

[0001] A PIPE CONNECTOR FOR CONNECTING PIPES

[0002] OF DIFFERENT MATERIALS

[0003] FIELD

[0004] This invention relates to a pipe connector for connecting pipes or pipe fittings. The invention also extends to a pipeline installation including the pipe connector, and a method for connecting pipes and / or pipe fittings using the pipe connector.

[0005] This invention relates particularly, but not exclusively to a pipe connector for connecting a pipe or fitting made of one material, e.g. HDPE, to another pipe or fitting made of an incompatible or dissimilar material, e.g. PVC. It will be convenient to hereinafter describe the invention with reference to this example application. However, it is to be clearly understood that the invention is not to be limited to incompatible or dissimilar materials and is capable of broader application than this example application.

[0006] BACKGROUND

[0007] It is common to use HDPE pipes (high density polyethylene) for pipelines conveying gas or liquid fluids from one location to another. For example, HDPE pipes are often used in gas distribution, in oil and gas gathering, and in mining applications. Further, HDPE pipes can also be used for wastewater lines and mains water supply lines. One advantage of using HDPE is that it has a high strength and flexibility. It also has a high resistance to chemicals, and therefore it does not easily degrade when exposed to chemicals. However, HDPE is more difficult to join to other types of materials because no glue can be used to effectively join the HDPE to another material.

[0008] PVC pipe fittings are widely available in a range of sizes and types. One advantage of PVC fittings is that they are easy to fit and connect to an adjacent PVC pipe by solvent welding which can be done in the field with minimal equipment. PVC pipe fittings are often used on pipes because they are quick and easy to install on PVC pipes which in turn saves time and labour costs.

[0009] Consequently, a PVC pipe or pipe fitting is sometimes required to be connected in series to a HDPE pipe. It may be challenging to couple a PVC pipe fitting to a HDPE pipe because PVC and HDPE have different physical properties which affects their compatibility and their ability to be reliably joined together.

[0010] This has been a challenge for the pipeline industry for a long time and no satisfactory resolution has yet been found to this problem. One prior art approach has been to use flange connectors on the ends of PVC and HDPE pipes respectively. The radial flanges are brought into a face-to-face abutment and then a series of mechanical fasteners are passed through the abutting flanges to bolt them to each other. While this achieves an effective connection of a PVC fitting to a HDPE pipe it has its disadvantages.

[0011] Figure 1 A illustrates a prior art arrangement utilising this basic principle of providing face to face flanges that are mechanically attached to each other. In Figure 1A an axial end of a HDPE pipe is butt welded to an axial end of a HDPE adapter. The adapter has a radial flange for facilitating a mechanical attachment to an adjacent radial flange. Figure 1 B illustrates an adapter for mounting on an end of a HDPE pipe that can then be mechanically bolted to a corresponding radial flange on a PVC fitting.

[0012] As shown in Figure 1Athe radial flanges on respectively the HDPE adapter and the PVC adapter are mechanically attached to each other by means of bolts passing through both flanges at spaced intervals around their circumferences. The bolts clamp the radial flanges to each other and the flanges may be effectively sealed to each other by one or more O-rings sandwiched between the faces of the two flanges to avoid leakage from the pipe joint. In the illustrated embodiment, each flange has about eight bolts passed therethrough to mechanically connect the two components to each other.

[0013] A PVC pipe has a pipe end with a spigot that is received within a complementary socket on a PVC adapter. The PVC adaptor has a pipe section and a radial flange extending radially out therefrom. The spigot is inserted into the socket and glued to the socket and thereby the adaptor. The PVC adapter can then be joined to the HDPE adapter by a face-to-face attachment of the opposed radial flanges on respectively the HDPE and PVC adapters.

[0014] However, the mechanical connectors are complex and it will be appreciated that this is a costly solution because it involves the use of two additional fittings. Further, it is very time consuming to install this on a pipeline installation as it involves fastening eight different bolts on each connection. Another prior art arrangement for joining these pipes together is known as a rubber ring joint (RRJ) which is shown in Figure 1 C. The rubber ring joint involves a push fit fitting with a rubber ring joint. However, these rubber ring joints typically do not have strong axial retention and in some instances, have no axial retention at all. With these joints there is therefore a possibility or risk of HDPE and PVC pipes being pulled apart from each other due to movement of the surrounding soil, or thermal expansion of the associated pipes and pipe fittings. If a push fit sealing arrangement of PVC and HDPE pipes is pulled apart then liquid within the pipe can leak out of the pipe into the surrounding environment, e.g. the soil, which is undesirable. Therefore, a shortcoming of rubber ring joints is that they don’t create a permanent join that resists the HDPE and PVC components being pulled apart from each other in an axial direction.

[0015] The reference to prior art in the background above is not and should not be taken as an acknowledgment or any form of suggestion that the referenced prior art forms part of the common general knowledge in Australia or in any other country.

[0016] SUMMARY OF DISCLOSURE

[0017] It would be advantageous if a more efficient and cost-effective solution could be devised for operatively connecting pipes and / or pipe fittings, and in particular pipes and pipe fittings that are made of different or incompatible materials.

[0018] According to one aspect of the invention there is provided a pipe connector for mechanically connecting two pipes made of different materials while providing fluid communication between the pipes, comprising: an inner member made of a first material that comprises a conduit section having a shoulder extending radially outward therefrom; and a surround member made of a second material that is different to the first material, the surround member comprising a further conduit section and a locking section extending axially away from the conduit section, wherein the locking section is configured to extend behind at least part of the shoulder and resist movement of the surround member in an axial direction away from the inner member whereby to mechanically connect the inner member and surround member to each other.

[0019] The locking section may be configured to extend behind an axial end of the shoulder proximate to said conduit section to resist the surround member being pulled off the inner member, e.g. in an axial direction. At least a part of the locking section may be continuous with the further conduit section.

[0020] The locking section may comprise a sleeve continuous with the further conduit section that circumferentially surrounds the inner member.

[0021] The locking section may further comprise at least one axial locking formation that extends behind at least part of the shoulder and resists movement of the surround member in an axial direction away from the inner member.

[0022] The sleeve may comprise inner and outer surfaces extending between a proximate end adjacent to the further conduit section and a terminal end remote from the further conduit section.

[0023] The locking section may further comprise a ring, mounted over the shoulder, that is separately formed from the sleeve. The ring may have an axial length which is at least 50% of, substantially equal to, or slightly greater than, the axial length of the shoulder. The ring may have an axial length which is at least twice, at least three times, or at least four times a transverse thickness of the ring. The ring may have a main ring part (excluding any ring retainer part) which is substantially cylindrical, and / or which is substantially rectangular in in cross sectional shape.

[0024] The ring may circumferentially surround the shoulder. The ring may be positioned radially inward of the sleeve.

[0025] The shoulder may comprise an annularshoulderthat extends around the conduit section, e.g. fully circumferentially around the conduit section.

[0026] The ring may be formed of a material that is compatible with the sleeve and can be chemically joined to the sleeve. For example, the ring may be adhered or solvent welded to the sleeve. Further, the ring may be formed of the same material as the sleeve.

[0027] The pipe connector may further comprise a circumferential seal sandwiched between the shoulder and the ring for sealing the locking section to the shoulder.

[0028] The shoulder may define a circumferential groove for receiving the seal therein.

[0029] Said at least one axial locking formation may comprise a ring retainer projecting transversely away from the ring that extends behind the shoulder. For example, the ring retainer may extend transversely away from a terminal end of the ring and the ring retainer may be integrally formed with the ring.

[0030] Said at least one axial locking formation may further comprise a sleeve retainer, e.g. in addition to the ring retainer, extending transversely away from the sleeve that extends behind the shoulder.

[0031] The sleeve retainer may be integrally formed with the sleeve.

[0032] In this embodiment the sleeve retainer may be positioned axially outward of the ring retainer so that the ring retainer is sandwiched between the sleeve retainer and the shoulder.

[0033] In this embodiment the sleeve may extend along the full length of the shoulder. Further, in this embodiment the sleeve retainer may extend along part of the conduit section beyond the shoulder.

[0034] In accordance with one form of the invention during manufacture of the pipe connector, the ring may be fitted in position on the shoulder before the sleeve is formed on the fitted ring.

[0035] Further, the sleeve may be moulded on top of and extending across the fitted ring.

[0036] The sleeve retainer may also be moulded over and onto the conduit section of the inner member.

[0037] Yet further, the further conduit section of the surround member may be moulded together with the sleeve and the sleeve retainer over and onto the conduit section in the moulding operation.

[0038] Thus, both the further conduit section and the circumferential sleeve (of the surround member) may be moulded over and onto the inner member and the fitted ring section in a single moulding operation. The further conduit section and the circumferential sleeve may be moulded as an integral article by injection moulding.

[0039] In accordance with another form of the invention during manufacture of the pipe connector, the sleeve may extend along a part of the ring in an axial direction. The sleeve may be joined to the ring to resist movement of the sleeve relative to the ring, and the ring retainer may project transversely away from an end of the ring and extend behind the shoulder, e.g. to retain the surround member connected to the inner member.

[0040] The sleeve may be joined to the ring by adhesive or solvent welding.

[0041] In this further form the ring retainer extends behind the shoulder to connect the inner and surround members to each other. However, the circumferential sleeve does not have a sleeve retainer extending behind the shoulder.

[0042] In accordance with yet another form of the invention during manufacture of the pipe connector, a terminal end of the sleeve may be joined to a proximate end of the ring to resist movement of the sleeve relative to the ring, and the ring retainer may project transversely away from an opposite end of the ring and extend behind the shoulder, e.g. to retain the surround member connected to the inner member.

[0043] The terminal end of the sleeve may terminate short of the proximate end of the ring, and the terminal end of the sleeve may be joined to the proximate end of the ring.

[0044] The terminal end of the sleeve may be joined to the ring by welding including induction welding, spin welding, or ultrasonic welding.

[0045] The terminal end of the sleeve may be positioned adjacent to an end of the shoulder.

[0046] In this yet further form of the invention the ring retainer extends behind the shoulder to connect the inner and surround members to each other. However, the circumferential sleeve does not have a sleeve retainer extending behind the shoulder.

[0047] Thus, in these other forms of the invention the sleeve may extend along a part of the length of the shoulder. In this other embodiment the axial locking formation is provided by the ring retainer, and it does not have a sleeve retainer. In yet another embodiment the sleeve may terminate short of the ring, and optionally also short of the shoulder and it does not have a sleeve retainer.

[0048] The conduit section of the inner member may comprise a pipe coupling formation at an axial end thereof remote from the surround member for coupling to an adjacent pipe of the same material as the inner member.

[0049] The inner member may be formed of HDPE and the pipe coupling formation may comprise an axial end face for butt welding to an adjacent HDPE pipe. The further conduit section of the surround member may comprise a further pipe coupling formation at an axial end thereof remote from the inner member for coupling to a further adjacent pipe of the same material as the surround member.

[0050] The surround member may be formed of PVC, and the further adjacent pipe may also be formed of PVC.

[0051] The further pipe coupling formation may comprise a spigot or socket for receiving a complementary socket or spigot on said further adjacent pipe.

[0052] The pipe connector may further comprise any one or more of the features, or combination of features, of the pipe connector defined in any other aspect of the invention.

[0053] According to another aspect of the invention there is provided a pipe connector for mechanically connecting two pipes together while providing fluid communication between the pipes, comprising: an inner member that comprises a conduit section having a shoulder extending radially outward therefrom; and a surround member comprising a further conduit section and a locking section extending axially away from the conduit section, wherein the locking section is configured to extend behind at least part of the shoulder and resist movement of the surround member in an axial direction away from the inner member whereby to mechanically connect the inner member and surround member.

[0054] Thus, in this aspect of the invention the inner member and the surround member may conceivably be made of the same material.

[0055] The pipe connector may include any one or more of the features, or combination of features, of a pipe connector in accordance with any other aspect of the invention.

[0056] According to yet another aspect of the invention there is provided a pipe connector for mechanically connecting two pipes made of different materials while providing fluid communication between the pipes, comprising: an inner member made of a first material that comprises a conduit section having a shoulder extending radially outward therefrom; and a surround member made of a second material that is different to the first material, the surround member comprising a further conduit section and a locking section extending axially away from the conduit section, wherein the locking section comprises a circumferential sleeve continuous with the surround member that circumferentially surrounds the inner member and a sleeve retainer extending transversely away from the sleeve body that extends behind the shoulder, and a separately formed ring that circumferentially surrounds the shoulder and a ring retainer projecting transversely away from the ring that extends behind the shoulder, wherein the locking section is configured to extend behind at least part of the shoulder and resist movement of the surround member in an axial direction away from the inner member whereby to mechanically connect the inner member and surround member to each other.

[0057] The circumferential sleeve may be moulded over and onto the fitted ring.

[0058] The further conduit and locking sections may be over moulded onto the ring and inner member as an integral article in an injection moulding operation.

[0059] The shoulder may comprise a circumferential groove, and the circumferential seal may comprise a sealing O-ring received in the circumferential groove.

[0060] The circumferential seal may be sandwiched between the shoulder and the ring.

[0061] The circumferential sleeve may be moulded over and onto the fitted ring and the sleeve retainer may be moulded over and onto the conduit section of the inner member integral with the sleeve.

[0062] The pipe connector may further comprise any one or more features, or combination of features, of the pipe connector defined in any other aspect of the invention.

[0063] According to another aspect of the invention there is provided a method of manufacturing a pipe connector, comprising: providing an inner member formed of a first material comprising a shoulder extending radially outward therefrom; and providing a surround member formed of a second material (e.g. that is different to the first material) and locating the surround member over the inner member, wherein the surround member comprises a locking section that extends behind an axial surface of the shoulder to lock the surround member to the inner member.

[0064] Providing an inner member may comprise providing a conduit section on which the shoulder is formed towards one end of the inner member. Providing a surround member may comprise providing a further conduit section and a locking section.

[0065] Providing the locking section may further comprise providing a pre-moulded ring made from the second material and fitting the ring over the shoulder so that it extends circumferentially around the shoulder.

[0066] The locking section may further comprise a ring retainer extending from the ring forming an axial locking formation and said fitting the ring may comprise positioning the ring retainer behind the shoulder on the inner member.

[0067] The locking section may further comprise a sleeve retainer forming a further axial locking formation and said mounting the locking section onto the inner member may comprise positioning the sleeve retainer behind the shoulder on the inner member.

[0068] The sleeve retainer may be positioned axially outward of the ring retainer, and the method may comprise sandwiching the ring retainer between the sleeve retainer and the second axial end of the shoulder.

[0069] Providing a further conduit section and a locking section may comprise forming the further conduit section and at least part of the locking section on the inner member.

[0070] Providing a further conduit section and a locking section may comprise over moulding the further conduit and locking sections onto the inner member which is already premoulded. This may be done in accordance with over moulding techniques practised in the injection moulding arts.

[0071] Instead mounting the further conduit and locking sections on the inner member may comprise solvent welding an inner surface of the sleeve to an outer surface of the ring.

[0072] Further, instead mounting the further conduit and locking sections on the inner member may comprise welding an axial end of the sleeve to an axial end of the ring.

[0073] The pipe connector may include any one or more of the features, or combination of features, of a pipe connector in accordance with any other aspect of the invention.

[0074] According to another aspect of the invention there is provided a pipeline installation comprising: a pipe connector comprising: an inner member made of a first material that comprises a conduit section having a shoulder extending radially outward therefrom, and a surround member made of a second material that is different to the first material, the surround member comprising a further conduit section and a locking section extending axially away from the conduit section, wherein the locking section is configured to extend behind at least part of the shoulder and resist movement of the surround member in an axial direction away from the inner member; a first pipe coupled to the conduit section on the inner member; and a second pipe or pipe fitting coupled to the further conduit section on the surround member, wherein the connector provides fluid communication between the first and second pipes.

[0075] The pipe connector is suitable for mechanically connecting two pipes made of different materials to each other while providing fluid communication between the pipes.

[0076] The first pipe may be made of HDPE and the second pipe or pipe fitting may be made of PVC.

[0077] The pipe connector may include any one or more of the features, or combination of features, of a pipe connector in accordance with any other aspect of the invention.

[0078] According to yet another aspect of the invention there is provided a method of connecting two pipes or pipe fittings made of different materials, comprising: providing a pipe connector in accordance with any one of the other aspects of the invention; connecting the conduit section of the pipe connector to a first pipe formed of a first material; connecting the further conduit section of the pipe connector to a second pipe formed of a second material, whereby to form a connected pipeline comprising pipes formed of two different materials.

[0079] The pipe connector may include any one or more of the features, or combination of features, of a pipe connector in accordance with any other aspect of the invention.

[0080] According to yet another aspect of the invention there is provided a pipe connector for connecting two pipes made of different materials, comprising: an inner member or base member made of a first material comprising a conduit section, and a shoulder extending radially outward from the conduit section; and a surround member made of a second material that is different to the first material, the surround member comprising a further conduit section, and a locking section extending axially away from the further conduit section, wherein the locking section resists movement of the surround member in an axial direction away from the inner member whereby to connect the inner member and surround member to each other.

[0081] The locking section may comprise at least one axial locking formation that extends behind at least part of the shoulder.

[0082] The shoulder may comprise a first axial end remote from the conduit section and a second axial end proximate to the conduit section, and a shoulder surface extending between its first and second axial ends.

[0083] The axial locking formation may extend behind at least part of the second axial end of the shoulder to physically resist movement of the surround member in an axial direction away from the inner member.

[0084] The locking section may further comprise a ring section circumferentially surrounding at least part of the shoulder on the inner member.

[0085] The ring section may comprise a first axial end, and an opposed second axial end remote from the further conduit section of the surround member, and an inner surface and an outer surface extending between its first and second axial ends.

[0086] The locking section may further comprise a ring retainer that forms a said axial locking formation extending behind the shoulder.

[0087] The ring retainer may be positioned at ortowards the second axial end of the ring section.

[0088] In one form the ring retainer may comprise a wall extending radially inward from the ring section, e.g. that extends substantially around the full circumference of the ring section.

[0089] The pipe connector may further comprise a circumferential seal sandwiched between the shoulder surface and the surround member for sealing the surround memberto the inner member. The shoulder may comprise a circumferential groove formed in the shoulder surface, and the circumferential seal may comprise a sealing O-ring received in the circumferential groove.

[0090] The circumferential seal may bear against the inner surface of the ring section.

[0091] The locking section may further comprise a sleeve circumferentially surrounding at least part of the shoulder on the inner member. In at least some embodiments, the sleeve indirectly circumferentially surrounds the shoulder because the ring section is interposed between the sleeve and the shoulder. Thus, the sleeve is not in direct contact with the shoulder.

[0092] The sleeve may comprise a first axial end and an opposite second axial end remote from the conduit section of the surround member. The sleeve may further comprise an inner surface and an outer surface extending between the first and second axial ends.

[0093] The inner surface of the sleeve may be fixed to the outer surface of the ring section to resist movement of the sleeve relative to the ring section.

[0094] The locking section may further comprise a sleeve retainer forming another axial locking formation extending radially inward from the sleeve and sitting behind the shoulder.

[0095] The sleeve retainer may comprise a wall or flange extending radially inward from the sleeve substantially around the full circumference of the ring section.

[0096] The sleeve retainer may extend across at least part of the ring retainer in a position that is axially outward of the ring retainer, so that the ring retainer is sandwiched between the sleeve retainer and the second axial end of the shoulder.

[0097] The ring section which is pre-moulded, may be fitted in position on the shoulder of the inner member which is also pre-moulded, with the circumferential seal sandwiched between the ring section and the shoulder.

[0098] In one embodiment of the invention the inner surface of the sleeve (of the locking section) may be fused with the outer surface of the ring section during manufacture of the pipe connector.

[0099] This may be done by over moulding the further conduit, sleeve, and sleeve retainer of the locking section onto the inner member and ring section, which are each pre-moulded. The over moulding may be performed in accordance with known injection moulding techniques.

[0100] In another embodiment of the invention which does not comprise over moulding, the sleeve may extend across at least part of the outer surface of the ring section, and the inner surface of the sleeve may be joined to the outer surface of the ring section by a chemical joining process or technique.

[0101] Optionally, the sleeve may extend across most of the outer surface of the ring section and the inner surface of the sleeve may be solvent welded to the outer surface of the ring section.

[0102] In this embodiment the sleeve may terminate short of the ring retainer and does not have a sleeve retainer extending behind the shoulder for additional retention like the previous embodiment.

[0103] In yet another embodiment of the invention which does not comprise over moulding, the sleeve may have an axial end, e.g. that is remote from the further conduit section, that terminates short of the ring section in an axial direction, and the axial end of the sleeve may be joined to the first axial end of the ring section to connect the sleeve and ring sections together and resist their separation.

[0104] The first axial end of the sleeve may be joined to the first axial end of the ring section by welding. In some example embodiments the sleeve is welded to the ring section by induction welding, spin welding, or ultrasonic welding.

[0105] Once again in this embodiment there is no sleeve retainer extending behind the shoulder to assist with retention in this embodiment.

[0106] The conduit section may be positioned towards one end of the inner member, and the shoulder may be positioned towards the other end of the inner member.

[0107] The pipe connector may include any one or more of the features, or combination of features, of a pipe connector in accordance with any other aspect of the invention.

[0108] BRIEF DESCRIPTION OF DRAWINGS

[0109] A pipe connector for operatively connecting pipes or pipe fittings to each other and a pipeline installation in accordance with the invention may be implemented in several different forms. It will be convenient to hereinafter describe in detail several embodiments of the invention with reference to accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However, it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding summary section. The Detailed Description refers to the accompanying drawings, in which:

[0110] Figure 1 A is a schematic drawing of a prior art arrangement for operatively connecting two pipes of dissimilar materials to each other;

[0111] Figure 1 B illustrates two different examples of prior art adaptors having a radial flange of the type that can be used on the prior art arrangement shown in Figure 1 A;

[0112] Figure 1 C is a schematic drawing of a different prior art arrangement for connecting together two pipes made of dissimilar materials;

[0113] Figure 2 is a schematic cross-sectional view of a pipe connector in accordance with one embodiment of the invention;

[0114] Figure 3 is an exploded perspective view of the pipe connector in Figure 2, together with a cutaway perspective view thereof providing some additional detail;

[0115] Figure 4 is a cross-sectional view of a pipe connector that is a variation on the pipe connector in Figure 2;

[0116] Figure 5 is an exploded perspective view of the pipe connector in Figure 4;

[0117] Figure 6 is a basic schematic cross-sectional view of a pipe connector in accordance with another embodiment of the invention illustrating the basic principles of the invention;

[0118] Figure 7 is a schematic cross-sectional view of a pipe connector in accordance with yet another embodiment of the invention;

[0119] Figure 8 is a schematic cross-sectional view of a pipe connector in accordance with yet another embodiment of the invention; and

[0120] Figure 9 is a schematic plan view showing how the pipe connector in any one of Figures

[0121] 2 to 8 may be used to operatively connect a PVC pipe fitting to a HDPE pipe. DETAILED DESCRIPTION

[0122] Figures 1A to 1 C illustrate example prior art arrangements for operatively connecting a HDPE pipe to a PVC pipe or pipe fitting. As these have already been described in the background section above, they will not be described further in this detailed description.

[0123] Figure 2 illustrates a cross-sectional view of a pipe connector in accordance with a first embodiment of the invention and Figure 3 is an exploded perspective view of the pipe connector in Figure 2.

[0124] In Figures 2 and 3 the pipe connector 10 comprises an inner member or base member 12 made of a first material comprising a conduit section 14 that is substantially cylindrical, and a shoulder 16 extending radially outward from the conduit section 14 towards one end of the inner member 12. The inner member 12 has first and second axial ends 12A and 12B and defines a flow passage therethrough.

[0125] The pipe connector 10 further comprises a surround member 20 made of a second material that circumferentially surrounds the shoulder 16. The surround member 20 comprises a further conduit section 22 and a locking section 26 extending behind the second axial end 18 of the shoulder 16 to hold the base and surround members 12 and 20 together. In Figures 2 and 3 the further conduit section 22 is substantially cylindrical.

[0126] The locking section 26 comprises a sleeve 50 and an axial locking formation in the form of a sleeve retainer 56 extending from the sleeve 50.

[0127] The locking section 26 in addition to the sleeve 50 further comprises a separately formed ring 30 circumferentially surrounding the shoulder 16 on the inner member 12 and sandwiched between the sleeve 50 and the shoulder 16. The ring is 30 made from the second material which is the same as that of the sleeve 50 and the further conduit section 22. The ring 30 comprises a first axial end, and a second opposed axial end remote from the further conduit section 22. The ring 30 further has an inner surface and an outer surface extending between the first and second axial ends.

[0128] The locking section 26 comprises a further axial locking formation in the form of a ring retainer or ring retaining formation 32 extending from the second axial end of the ring 30, that extends behind the second axial end 18 of the shoulder 16. In the illustrated embodiment the ring retainer 32 extends radially inward from the second axial end of the ring 30 around its full circumference. The sleeve 50 circumferentially surrounds the ring 30 and comprises a first sleeve end 52 and an opposite second or terminal sleeve end 54 (remote from the further conduit section 22 of the surround member 20). The sleeve 50 also includes inner and outer surfaces extending between the first and second sleeve ends 52, 54.

[0129] The inner surface of the sleeve 50 is fixed or joined to the outer surface of the ring 30 in the connector 10. By joining the sleeve 50 to the ring section 30, the retention provided by the ring retainer 32 can be transferred to the sleeve 50 and then the further conduit section 22 of the surround member 20.

[0130] In the embodiment illustrated in Figures 2 and 3 the sleeve retainer 56 extends behind the second axial end 18 of the shoulder 16 on the inner member 12 and across the ring retainer 32 in a position that is axially outward thereof. Thus, the ring retainer 32 is sandwiched between the sleeve retainer 56 and the second axial end 18 of the shoulder 16.

[0131] The shoulder 16 has a substantially cylindrical shoulder surface 34 extending between its first and second axial ends 17 and 18 thereof, and a circumferential groove 42 formed in the shoulder surface 34. A circumferential seal 40 is received in the circumferential groove 42 that is sandwiched between the shoulder surface 34, and the inner surface of the ring 30 for sealing the ring 30 and thereby the surround member 20 to the inner member 12.

[0132] In the embodiment in Figures 2 and 3, the further conduit section 22, the sleeve 50 and sleeve retainer 56 of the surround member 20 are integrally formed as a single component by injection moulding. After separately forming the ring 30 and fitting it on the shoulder 16, the further conduit section 22 is moulded onto the ring 30. In this step the further conduit section 22, sleeve 50 and sleeve retainer 56 of the surround member 20, are over moulded onto the pre-moulded inner member 12 and the pre-moulded fitted ring 30. As the ring 30 and the sleeve 50 are formed of the same material, the sleeve 50 fuses with the ring 30 during the over moulding process and effectively joins the sleeve 50 to the ring 30.

[0133] The conduit section 14 of the inner member 12 comprises a pipe coupling formation 60 at an axial end thereof remote from the surround member 20 for coupling to an adjacent pipe that may typically be formed of the same material as the inner member 12. In the illustrated embodiment the inner member 12 is formed of HDPE and the pipe coupling formation 60 comprises an axial end face for butt welding to an adjacent pipe of HDPE. In turn, the further conduit section 22 of the surround member 20 comprises a further pipe coupling formation 62 at an axial end thereof remote from the inner member 12 for coupling to an adjacent pipe or pipe fitting that may typically be formed of the same material such as PVC. In Figures 3 and 4 the further pipe coupling formation 62 comprises a spigot that is received in a complementary socket on said adjacent pipe or pipe fitting.

[0134] The pipe connector 10 shown in Figures 2 and 3 can be manufactured in the following way.

[0135] Firstly, an inner member 12 including the shoulder 16, and the groove 42 formed in the shoulder 16, is pre-moulded as a single discrete article in a first injection moulding operation. An O-ring such as a rubber sealing O-ring 40 is then mounted in the circumferential groove 42 on the shoulder 16.

[0136] A ring 30 with the ring retainer 32 on its second axial end is pre-moulded as a separate article in an injection moulding operation. Thereafterthe ring 30 is fitted circumferentially over the shoulder 16 on the inner member 12 so that it covers the sealing O-ring 40 in the position shown in Figures 2 and 3. The ring retainer 32 extends behind the second axial end 18 of the shoulder 16.

[0137] The further conduit section 22, the sleeve 50, and sleeve retainer 56 are then over moulded onto the inner member 12, having the fitted ring 30 mounted thereon, in a subsequent injection moulding operation. This enables the sleeve retainer 56 to be formed around the second axial end 18 of the shoulder 14 and the ring retainer 32, to provide additional and further resistance to preventing the surround member 20 being pulled off the inner member 12 in an axial direction. This mechanically locks the locking section 26 onto the inner member 12 and provides a single pipe connector 10 ready for use.

[0138] In use, as shown in Figure 9 the pipe connector 10 can be used in a pipeline installation 70 to connect an HDPE pipe 71 which is typically used for long lengths of gas and water pipes to a PVC pipe or pipe fitting 72, e.g. downstream of the HDPE pipe. In the illustrated embodiment the pipeline installation 70 is subterranean and is received in the ground.

[0139] The HDPE pipe 71 has a downstream end 74 that is buttwelded to the coupling formation

[0140] 60 on the inner member 12 which is also made of HDPE. The further coupling formation 62 on the free end of the surround member 20 is operatively coupled to an upstream end 76 of the PVC pipe or fitting 72. The further coupling formation 62 might typically be a spigot or socket coupling and be attached to a complementary socket or spigot, on the pipe or fitting 72.

[0141] It will readily be appreciated by a person skilled in the art that the coupling of these two pipes 71 and 72 through the pipe connector 10 can be accomplished quickly and efficiently with the pipe connector 10. Further, the two pipes 71 and 72 will resist being pulled part from each other. Thus, this connector 10 confers real advantages over prior art techniques of connecting these pipes described in the background above and illustrated in Figures 1A and 1 C.

[0142] Figures 4 and 5 show an exploded perspective view and cross-sectional view of a pipe connector that is a basic variation on the pipe connector in Figures 3 and 4.

[0143] In Figures 4 and 5, the same reference numerals will be used to refer to the same components unless otherwise indicated. Further, the following description will be focused on the differences between this embodiment and the earlier embodiment.

[0144] In Figures 4 and 5 the further coupling formation 62 on the free end of the surround member 20 forms a socket 66 for coupling to a spigot on an adjacent pipe or fitting. This is different to that in Figures 4 and 5 where the corresponding coupling formation on the end of the surround member 20 forms a spigot for receiving in a socket of an adjacent pipe or pipe fitting. The embodiments in Figures 2 and 4 are these basic variations on spigot and socket connections that are well known in the plumbing art. Other than this the structure and function of the pipe connector in Figures 4 and 5 is very similar to that described above with reference to Figures 2 and 3.

[0145] Figure 6 is a schematic illustration of a pipe connector in accordance with another embodiment of the invention that illustrates the broad principles of the invention.

[0146] Once again, the embodiment in Figure 6 has similarities with the embodiments in Figures 2 and 3, and the same reference numerals will be used to refer to the same components unless otherwise indicated. Further, the following description will be focused on the differences between this embodiment and the earlier embodiment.

[0147] In Figure 6 the pipe connector which is indicated generally by numeral 10 comprises an inner member 12 which may be made of a first material such as HDPE comprising a substantially cylindrical conduit section 14, e.g. for coupling to an adjacent upstream pipe made of HDPE. The inner member 12 further comprises a shoulder 16 extending radially outward from the conduit section 14 towards one end of the inner member 12. The shoulder 16 has a first axial end 17 remote from the conduit section 14 and a second axial end 18 proximate to the conduit section 14.

[0148] The pipe connector 10 further comprises a surround member 20 made of a second material, e.g. HDPE, that is different to the first material of the inner member 12. The second material of the surround member 20 may be incompatible with that of the inner member 12 in the sense that it cannot be welded to the first material. The surround member 20 comprises a substantially cylindrical further conduit section 22, e.g. for coupling to an adjacent downstream pipe, and a locking section 26 extending axially away from the further conduit section 22 in a direction towards the inner member 12 for mechanically connecting to the shoulder 16 on the inner member 12.

[0149] The surround member 20 is configured to circumferentially surround at least part of the shoulder 16 and to resist movement of the surround member 20 away from the inner member 12. To achieve this the locking section 26 comprises a sleeve 50 and a first axial locking formation comprising a sleeve retainer 56 that extends behind the second axial end 18 of the shoulder 16 to physically resist movement of the surround member 20 in an axial direction away from the inner member 12. This thereby holds the inner and surround members 12 and 20 together.

[0150] Thus, this embodiment does not have a ring mounted over the shoulder 16 made of the same material as the surround member 20. Instead, the sleeve 50 is mounted directly onto the shoulder 16. Other than this difference the structure and function of the pipe connector in Figure 6 is similar in structure and function to that described above with reference to Figures 2 and 3.

[0151] Figure 7 illustrates a pipe connector in accordance with yet another embodiment of the invention. In Figure 7 the same reference numerals will be used to refer to the same components unless otherwise indicated. Further, the following description will be focused on the differences between this embodiment and the earlier embodiment.

[0152] In the Figure 7 embodiment, the inner surface of the sleeve 50 is joined to the outer surface of the ring 30 by a chemical process that typically comprises solvent welding. In this embodiment the sleeve 50 is joined to the ring 30, after the ring 30 and the sleeve 50 have each been separately moulded prior to being fitted together. To do this the inner surface of the sleeve 50 is solvent welded onto the outer surface of the ring 30. This solvent welding causes the materials of the sleeve 50 and ring 30 to intermix with each other and merge together. This produces a strong weld as would be known to persons skilled in the art of solvent welding.

[0153] In Figure 7 the sleeve 50 of the surround member 20 overlaps with the ring 30 but terminates short of the second axial end of the ring 30 and does not have a sleeve retainer extending behind the shoulder 16 (unlike the embodiment in Figures 2 and 3). However, in common with the embodiment in Figures 2 and 3 the pipe connector 10 has an axial locking formation comprising a ring retainer 32 extending transversely away from the ring 30 that is positioned behind the second axial end 18 of the shoulder 16. This ring retainer 32 resists separation of the base and surround members 12 and 20.

[0154] Thus, the pipe connector 10 in Figure 7 relies on the solvent welding of the sleeve 50 to the ring 30 and the locking retention provided by the ring retainer 32 positioned behind the second axial end 18 of the shoulder 16 to resist separation of the inner and surround members 12 and 20. It may therefore not be as strong as the embodiment in Figures 2 and 3. Other than these differences the structure and function of the pipe connector in Figure 6 is similar in structure and function to that described above with reference to Figures 2 and 3.

[0155] Figure 8 illustrates a pipe connector in accordance with yet another embodiment of the invention. In Figure 8 the same reference numerals will be used to refer to the same components unless otherwise indicated. Further, the following description will be focused on the differences between this embodiment and the earlier embodiment.

[0156] As with the Figure 7 embodiment, the Figure 8 embodiment has an axial locking formation comprising a ring retainer 32 extending from the ring 30 that is positioned behind the second axial end 18 of the shoulder 16 and provides locking retention that resists separation of the inner member 12 and the surround member 20.

[0157] In the Figure 8 embodiment as shown in the drawings the locking section 26 of the surround member 20 comprises a sleeve 50 having a terminal end that terminates short of the ring, e.g. a proximate or near end of the ring 30, in an axial direction. Thus, the sleeve 50 has a first axial end or terminal end 80 that is joined to the adjacent first axial end 82 of the ring 30 to join the sleeve 50 and ring 30 together. This thereby mechanically connects the surround member 20 to the inner member 12 and resists their separation from each other by being pulled apart. In this embodiment which has a reduced area of face contact when compared with the Figure 7 embodiment, the first axial end 80 of the sleeve 50 is joined to the adjacent first axial end 82 of the ring 30 by welding. One or more of induction welding, spin welding, or ultrasonic welding techniques may be used to weld the components to each other.

[0158] In this embodiment as with the previous embodiment illustrated in Figures 7 and 8 mechanical locking or retention is provided by the ring retainer 32 that is positioned behind the second axial end 18 of the shoulder 16 and the strength with which the first axial or terminal end 80 of the sleeve 50 is fixed or joined to the adjacent first axial end of the ring section 30. Once again, this embodiment does not have a sleeve retainer (like that in the first embodiment in Figures 3 to 6) to aid retention of the surround member 20 on the inner member 12.

[0159] In Figure 8 the connector 10 is shown with a taper on the inner member extending from one end to the other. In a variation of this embodiment that is not shown the inner member has a constant circular cross-sectional configuration along its length and does not have a taper from one end to the other. It comprises a cylinder of constant diameter along its length.

[0160] Figure 9 is a schematic plan view showing how the apparatus may be used to operatively connect a PVC pipe fitting to a HDPE pipe.

[0161] As described above the free end of the inner member 12 made of HDPE may be butt welded to an adjacent end of a HDPE pipe 71. Further, the free end of the surround member 20 may be operatively connected to an adjacent PVC pipe or fitting 72 by a spigot socket connection. This way a pipeline installation is provided that securely attaches the pipes and fittings to each other while providing fluid communication through the pipes.

[0162] An advantage of the pipe connector described above in the detailed description with reference to Figures 2 to 9 is that it provides a connector that effectively and efficiently connects HDPE pipes or fittings to PVC pipes or fittings. Further, it provides a secure connection that resists the pipes or fittings from being pulled apart in an axial direction. Yet further, the pipe connector can be manufactured reasonably efficiently and at a reasonable cost. Yet further, the pipe connector can be installed quickly and efficiently in the field when compared with some prior art techniques such as those described in the background section. In the illustrated embodiments the pipe connector is configured such that the base and surround members are effectively held to each other by a mechanical arrangement. More specifically, in each of the illustrated embodiments the surround member has an axial locking formation that is configured to sit behind the shoulder of the inner member and resists separation of the inner member and surround member when a force is applied to them in a direction that would pull them apart.

[0163] A further advantage of the apparatus described above with reference to Figures 2 to 5, is that a part of the surround member can be injection moulded onto the inner member with an integrally formed locking section retainer that extends around the shoulder. This is achieved with an injection moulding step in which the further conduit and locking sections are over moulded onto the pre-moulded inner member and fitted ring section.

[0164] The inner member can be connected to an adjacent pipe of the same material (which it is therefore compatible therewith) in accordance with conventional and known techniques. For example, the inner member made of HDPE can be operatively connected or fixed to an adjacent section of HDPE pipe by means of conventional techniques such as butt welding of the adjacent pipe end and conduit section of the inner member. Similarly, the surround member, which is made of a different material, e.g. PVC can be operatively connected and fixed to a PVC pipe fitting, using known forms of connection of PVC pipes and pipe fittings to each other. These include the use of complementary pipe couplings using spigot socket connections.

[0165] In this specification, the term ‘comprising’ is intended to denote the inclusion of a stated integer or integers, but not necessarily the exclusion of any other integer, depending on the context in which that term is used. This applies also to variants of that term such as ‘comprise’ or ‘comprises’.

[0166] It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. All such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is set forth herein. Changes in detail or structure may be made without departing from the basic elements of the invention as defined in the following claims.

Claims

CLAIMS:1 . A pipe connector for mechanically connecting two pipes made of different materials while providing fluid communication between the pipes, comprising: an inner member made of a first material that comprises a conduit section having a shoulder extending radially outward therefrom; and a surround member made of a second material that is different to the first material, the surround member comprising a further conduit section and a locking section extending axially away from the conduit section, wherein the locking section is configured to extend behind at least part of the shoulder and resist movement of the surround member in an axial direction away from the inner member whereby to mechanically connect the inner member and surround member to each other.

2. A pipe connector according to claim 1 , wherein the locking section comprises at least one axial locking formation that extends behind at least part of the shoulder and resists movement of the surround member in an axial direction away from the inner member.

3. A pipe connector according to claim 2, wherein the locking section further comprises a sleeve continuous with the further conduit section that circumferentially surrounds the inner member.

4. A pipe connector according to any one of claim 3, wherein the locking section further comprises a separately formed ring mounted on the shoulder.

5. A pipe connector according to claim 4, wherein the ring is formed of a material that is compatible with the sleeve and can be chemically joined to the sleeve.

6. A pipe connector according to claim 5, wherein the ring is formed of the same material as the sleeve.

7. A pipe connector according to any one of claims 4 to 6, further comprising a circumferential seal sandwiched between the shoulder and the ring for sealing the locking section to the shoulder.

8. A pipe connector according to any one of claims 4 to 7, wherein the axial locking formation comprises a ring retainer projecting transversely away from the ring that extends behind the shoulder.

9. A pipe connector according to any one of claims 2 to 7, wherein the axial locking formation comprises a sleeve retainer extending transversely away from the sleeve that extends behind the shoulder.

10. A pipe connector according to claim 9, further comprising a ring retainer projecting transversely away from the ring.

11. A pipe connector according to claim 10, wherein the sleeve retainer is positioned axially outward of the ring retainer so that the ring retainer is sandwiched between the sleeve retainer and the shoulder.

12. A pipe connector according to any one of claims 4 to 11 , wherein the ring is fitted in position on the shoulder before the sleeve is formed on the fitted ring.

13. A pipe connector according to claim 12, wherein the sleeve is moulded on top of and extending across the fitted ring.

14. A pipe connector according to claim 13, when dependent on claim 9, wherein the sleeve retainer is moulded over and onto the conduit section of the inner member.

15. A pipe connector according to claim 13 or claim 14, wherein the further conduit section of the surround member is moulded together with the sleeve onto the conduit section.

16. A pipe connector according to claim 8, wherein the sleeve extends along at least a part of the ring in an axial direction.

17. A pipe connector according to claim 16, wherein the sleeve is joined to the ring to resist movement of the sleeve relative to the ring and the ring retainer projects transversely away from an end of the sleeve and extends behind the shoulder.

18. A pipe connector according to claim 17, wherein the sleeve is joined to the ring by adhesive or solvent welding.

19. A pipe connector according to claim 8, wherein an end of the sleeve is joined to an end of the ring to resist movement of the sleeve relative to the ring and the ringretainer projects transversely away from an end of the ring and extends behind the shoulder.

20. A pipe connector according to claim 19, wherein the terminal end of the sleeve terminates short of a proximate end of the ring, and the terminal end of the sleeve is joined to the proximate end of the ring.21 . A pipe connector according to claim 20, wherein the terminal end of the sleeve is joined to the ring by welding, including induction welding, spin welding, or ultrasonic welding.

22. A pipe connector according to any one of claims 1 to 21 , wherein the conduit section of the inner member comprises a pipe coupling formation at an axial end thereof remote from the surround member for coupling to an adjacent pipe of the same material as the inner member.

23. A pipe connector according to claim 22, wherein the inner member is formed of HDPE and the pipe coupling formation comprises an axial end face for butt welding to an end of an adjacent HDPE pipe.

24. A pipe connector according to any one of claims 1 to 23, wherein the further conduit section of the surround member comprises a further pipe coupling formation at an axial end thereof remote from the inner member for coupling to a further adjacent pipe of the same material as the surround member.

25. A pipe connector according to claim 24, wherein the surround member is formed of PVC, and the further adjacent pipe is formed of PVC, and the further pipe coupling formation comprises a spigot or socket for receiving a complementary socket or spigot on said further adjacent pipe.

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