Esslemont, Hamish Ian (North Mains, Auchenhove Lumphanan, Kincardineshire AB31 4QR, GB)
Mclaughlin, Thomas Kilpatrick (30 Eigie Crescent, Balmedie, Aberdeenshire AB23 8WH, GB)
Mudge, Joseph Krist (22 Cults Avenue, Aberdeen AB15 9RS, GB)
Esslemont, Hamish Ian (North Mains, Auchenhove Lumphanan, Kincardineshire AB31 4QR, GB)
Mclaughlin, Thomas Kilpatrick (30 Eigie Crescent, Balmedie, Aberdeenshire AB23 8WH, GB)
| 1. | A pipe connection assembly (100; 300) comprising, for each pipe connection (100; 300), two pipe ends (10A, lOB; 210A, 210B), a sleeve (102), and a resilient seal ring (110); each pipe end (lOA, lOB; 210A, 210B) comprising a torque shoulder (18A, 18B), and a ring entrapment surface (22A, 22B) located radially inwardly of the pipe end (10A, lOB; 210A, 210B) torque shoulder (18A, 18B); where at least a portion of one of the ring entrapment surfaces (22A, 22B) is angled radially inwardly toward the other ring entrapment surface (22A, 22B); the sleeve (102) having two sleeve torque shoulders (106) substantially complementary to the pipe end (10A, lOB; 210A, 210B) torque shoulders (18A, 18B); whereby the configuration of the resilient seal ring (110) and of the ring entrapment surfaces (22A, 22B) cooperate to retain the resilient seal ring (110) within an annular cavity defined between the ring entrapment surfaces (22A, 22B) of the two pipe ends (10A, lOB; 210A, 210B). |
| 2. | A pipe connection assembly (100; 300) according to claim 1, wherein the pipe end (10A, lOB; 210A, 210B) torque shoulder (18A, 18B) tapers inwardly away from the axial extremity (20) of the pipe. |
| 3. | A pipe connection assembly (100; 300) according to either of claims 1 or 2, wherein the sleeve (102) has a substantially complementary form to the pipe ends (10A, lOB; 210A, 210B) at each axial end of the sleeve (102) radially inwards up to as far as, but not including, the ring entrapment surface (22A, 22B). |
| 4. | A pipe connection assembly (100; 300) according to any of the preceding claims, wherein the resilient seal ring (110) is dimensioned to be trapped, in the fully madeup pipe connection (100; 300), within the annular cavity defined between the ring entrapment surfaces (22A, 22B) of the two pipe ends (lOA, lOB; 210A, 210B). |
| 5. | A pipe connection assembly (100; 300) according to claim any of the preceding claims, wherein the sleeve (102) further comprises a ringsupporting surface (108) extending between the two torque shoulders (106) of the sleeve (102). |
| 6. | A pipe connection assembly (100; 300) according to claim 5, wherein the annular cavity is defined by the ring entrapment surfaces (22A, 22B) of the two pipe ends (10A, lOB; 210A, 210B), and the ringsupporting surface (108) of the sleeve (102). |
| 7. | A pipe connection assembly (100; 300) according to any of the preceding claims, wherein each pipe end (10A, lOB; 210A, 210B) further comprises an external screw thread (14). |
| 8. | A pipe connection assembly (100; 300) according to any preceding claim, wherein each pipe end (10A, lOB; 210A, 210B) further comprises a sealing surface (16A, 16B) tapering inwardly towards the axial extremity (20) of the pipe. |
| 9. | A pipe connection assembly (100; 300) according to any preceding claim, wherein each pipe end (10A, lOB; 210A, 210B) further comprises, radially inwards from the radially outermost part of the pipe end (10A, lOB; 210A, 210B), an external screw thread (14) and a sealing surface (16A, 16B) tapering inwardly towards the axial extremity (20) of the pipe. |
| 10. | A pipe connection assembly (100; 300) according to any preceding claim, wherein the sleeve (102) further comprises the torque shoulder (106) tapering outwardly away from the respective axial end of the sleeve (102). |
| 11. | A pipe connection assembly (100; 300) according to any preceding claim, wherein the sleeve (102) further comprises a sealing surface (104) tapering outwardly towards the respective axial end of the sleeve (102). |
| 12. | A pipe connection assembly (100; 300) according to any preceding claim, wherein the sleeve (102) further comprises an internal screw thread. |
| 13. | A pipe connection assembly (100; 300) according to any preceding claim, wherein the sleeve (102) further comprises, radially outwards from the radially innermost part of the sleeve, the torque shoulder (18A, 18B) tapering outwardly away from the respective axial end of the sleeve (102), a sealing surface (104) tapering outwardly towards the respective end of the sleeve (102), and an internal screw thread. |
| 14. | A pipe connection assembly (100; 300) according to any preceding claim, wherein the ring entrapment surface (22A, 22B) of each pipe end (10A, lOB; 210A, 210B) is a ring entrapment shoulder (22A, 22B). |
| 15. | A pipe connection assembly (100; 300) according to claim 14, wherein the ring entrapment shoulder (22A, 22B) tapers inwardly towards the axial extremity (20) of the pipe. |
| 16. | A pipe connection assembly (100; 300) according to any of claims 5 to 15, wherein the ring supporting surface (108) of the sleeve (102) is cylindrical and concentric with the longitudinal axis of the sleeve (102). |
| 17. | A pipe connection assembly (100; 300) according to any of claims 14 to claim 16 when dependant on claim 5, wherein the resilient seal ring (110) has a cross sectional shape which substantially matches the shape of the annular cavity defined between the respective ring entrapment shoulders (22A, 22B) of the two pipe ends (lOA, lOB; 210A, 210B), and the ring supporting surface (108) of the sleeve (102). |
| 18. | A pipe connection assembly according to claim 17, wherein the resilient seal ring (108) has a cross sectional dimension causing it to be an interference fit with the annular cavity whereby the resilient seal ring (108) is compressed in the madeup assembly (100; 300). |
| 19. | A pipe connection assembly (100; 300) according to any preceding claim, wherein the resilient seal ring (110) is formed from a corrosion resistant material thereby forming a corrosion resistant ring (110). |
| 20. | A pipe connection assembly (100; 300) comprising, for each pipe connection (100; 300), two pipe ends (1or, lOB; 210A, 210B), a sleeve (102), and a resilient seal ring (110); each pipe end (lOA, lOB; 210A, 210B) comprising a torque shoulder (18A, 18B) tapering inwardly away from the axial extremity (20) of the pipe, and a ring entrapment surface (22A, 22B) located radially inwardly of the pipe end (lOA, lOB; 210A, 210B) torque shoulder (18A, 18B); the sleeve (102) having two sleeve torque shoulders (106) substantially complementary to the pipe end (10A, lOB; 210A, 210B) torque shoulders (18A, 18B); whereby the configuration of the resilient seal ring (110) and of the ring entrapment surfaces (22A, 22B) cooperate to retain the resilient seal ring (110) within an annular cavity defined between the ring entrapment surfaces (22A, 22B) of the two pipe ends (lOA, lOB; 210A, 210B). |
| 21. | A pipe connection assembly (100; 300) according to claim 20, wherein at least a portion of one of the ring entrapment surfaces (22A, 22B) is angled radially inwardly toward the other ring entrapment surface (22A, 22B) . |
| 22. | A pipe connection assembly (100; 300) according to either of claims 20 or 21, wherein the sleeve (102) has a substantially complementary form to the pipe ends (lOA, lOB; 210A, 210B) at each axial end of the sleeve (102) radially inwards up to as far as, but not including, the ring entrapment surface (22A, 22B). |
| 23. | A pipe connection assembly (100; 300) according to any of claims 20 to 22, wherein the resilient seal ring (110) is dimensioned to be trapped, in the fully made up pipe connection (100; 300), within the annular cavity defined between the ring entrapment surfaces (22A, 22B) of the two pipe ends (10A, lOB; 210A, 210B). |
| 24. | A pipe connection assembly (100; 300) according to any of claims 20 to 23, wherein the sleeve (102) further comprises a ringsupporting surface (108) extending between the two torque shoulders (106) of the sleeve (102). |
| 25. | A pipe connection assembly (100; 300) according to claim 24, wherein the annular cavity is defined by the ring entrapment surfaces (22A, 22B) of the two pipe ends (lOA, lOB; 210A, 210B), and the ringsupporting surface (108) of the sleeve (102). |
| 26. | A pipe connection assembly (100; 300) according to any of claims 20 to 25, wherein each pipe end (10A, lOB; 210A, 210B) further comprises an external screw thread (14). |
| 27. | A pipe connection assembly (100; 300) according to any of claims 20 to 26, wherein each pipe end (10A, lOB; 210A, 210B) further comprises a sealing surface (16A, 16B) tapering inwardly towards the axial extremity (20) of the pipe. |
| 28. | A pipe connection assembly (100; 300) according to any of claims 20 to 27, wherein each pipe end (10A, lOB; 210A, 210B) further comprises, radially inwards from the radially outermost part of the pipe end (10A, lOB; 210A, 210B), an external screw thread (14) and a sealing surface (16A, 16B) tapering inwardly towards the axial extremity (20) of the pipe. |
| 29. | A pipe connection assembly (100; 300) according to any of claims 20 to 28, wherein the sleeve (102) further comprises the torque shoulder (106) tapering outwardly away from the respective axial end of the sleeve (102). |
| 30. | A pipe connection assembly (100; 300) according to any of claims 20 to 29, wherein the sleeve (102) further comprises a sealing surface (104) tapering outwardly towards the respective axial end of the sleeve (102). |
| 31. | A pipe connection assembly (100; 300) according to any of claims 20 to 30, wherein the sleeve (102) further comprises an internal screw thread. |
| 32. | A pipe connection assembly (100; 300) according to any of claims 20 to 31, wherein the sleeve (102) further comprises, radially outwards from the radially innermost part of the sleeve, the torque shoulder (18A, 18B) tapering outwardly away from the respective axial end of the sleeve (102), a sealing surface (104) tapering outwardly towards the respective end of the sleeve (102), and an internal screw thread. |
| 33. | A pipe connection assembly (100; 300) according to any of claims 20 to 32, wherein the ring entrapment surface (22A, 22B) of each pipe end (lOA, lOB; 210A, 210B) is a ring entrapment shoulder (22A, 22B). |
| 34. | A pipe connection assembly (100; 300) according to claim 33, wherein the ring entrapment shoulder (22A, 22B) tapers inwardly towards the axial extremity (20) of the pipe. |
| 35. | A pipe connection assembly (100; 300) according to any of claims 24 to 34, wherein the ring supporting surface (108) of the sleeve (102) is cylindrical and concentric with the longitudinal axis of the sleeve (102). |
| 36. | A pipe connection assembly (100; 300) according to any of claims 33 to 35 when dependant on claim 24, wherein the resilient seal ring (110) has a cross sectional shape which substantially matches the shape of the annular cavity defined between the respective ring entrapment shoulders (22A, 22B) of the two pipe ends (10A, lOB; 210A, 210B), and the ring supporting surface (108) of the sleeve (102). |
| 37. | A pipe connection assembly according to claim 36, wherein the resilient seal ring (108) has a cross sectional dimension causing it to be an interference fit with the annular cavity whereby the resilient seal ring (108) is compressed in the madeup assembly (100; 300). |
| 38. | A pipe connection assembly (100; 300) according to any of claims 20 to 37, wherein the resilient seal ring (110) is formed from a corrosion resistant material thereby forming a corrosion resistant ring (110). |
| 39. | A pipe for use in a pipe connection assembly (100; 200) according to any of claims 1 to 19, one or both ends (lOA, lOB; 210A, 210B) of the pipe comprising a respective torque shoulder (18A, 18B), and a respective ring entrapment surface (22A, 22B) located radially inwardly of the pipe end torque shoulder (18A, 18B). |
| 40. | A final pipe end connection component comprising one pipe end (10A, lOB; 210A, 210B) and a sleeve (102) in a one piece unit, and a resilient seal ring (110), for attachment to the pipe end (lOA, lOB; 210A, 210B) of a pipe in accordance with claim 39 which forms the last of a series of pipe made up with the pipe connection assembly (100; 300) in accordance with any of claims 1 to 19. |
| 41. | A pipe for use in a pipe connection assembly (100; 200) according to any of claims 20 to 38, one or both ends (10A, 10B; 210A, 210B) of the pipe comprising a respective torque shoulder (18A, 18B), and a respective ring entrapment surface (22A, 22B) located radially inwardly of the pipe end torque shoulder (18A, 18B). |
| 42. | A final pipe end connection component comprising one pipe end (lOA, lOB; 210A, 210B) and a sleeve (102) in a one piece unit, and a resilient seal ring (110), for attachment to the pipe end (lOA, lOB; 210A, 210B) of a pipe in accordance with claim 41 which forms the last of a series of pipe made up with the pipe connection assembly (100; 300) in accordance with any of claims 20 to 38. |
Various forms of pipe connector are known for field use in the oil industry. A particular form of connector which is known under the Trade Mark "VAM" comprises a combination of shaped and externally threaded pipe ends, plus an internally threaded sleeve. VAM- compatible pipe ends are both externally and internally tapered such as to form an axially projecting shoulder radially intermediate the inside and outside diameters of the pipe. The matching sleeve is also double- tapered at each end in a form that is complementary to the pipe ends to provide a pair of circumferential grooves that are aligned in mutually opposite axial directions for seating the shoulder of a respective one of the two pipe ends to be mutually connected by the sleeve. Typically, the pipes (including the pipe ends) and the sleeve are formed of metal which is desirably given a surface coating to protect against corrosion,
particularly at the regions of contact between the pipe ends and the sleeve where they are exposed to the fluids carried within the pipe during its use.
However, plastics anti-corrosion coatings applied to these regions tend to be disrupted and dispersed by the forces involved in tightening a VAM-type connector, leaving the metal exposed to corrosive influences.
According to a first aspect of the present invention there is provided pipe connection assembly comprising, for each pipe connection, two pipe ends, a sleeve, and a resilient seal ring; each pipe end comprising a torque shoulder, and a ring entrapment surface located radially inwardly of the pipe end torque shoulder; where at least a portion of one of the ring entrapment surfaces is angled radially inwardly toward the other ring entrapment surface; the sleeve having two sleeve torque shoulders substantially complementary to the pipe end torque shoulders; whereby the configuration of the resilient seal ring and of the ring entrapment surfaces co-operate to retain the resilient seal ring within an annular cavity defined between the ring entrapment surfaces of the two pipe ends.
Preferably, the pipe end torque shoulder tapers inwardly away from the axial extremity of the pipe.
According to a second aspect of the present invention there is provided a pipe connection assembly comprising, for each pipe connection, two pipe ends, a sleeve, and a resilient seal ring; each pipe end comprising a torque shoulder tapering inwardly away from the axial extremity of the pipe, and
a ring entrapment surface located radially inwardly of the pipe end torque shoulder; the sleeve having two sleeve torque shoulders substantially complementary to the pipe end torque shoulders; whereby the configuration of the resilient seal ring and of the ring entrapment surfaces co-operate to retain the resilient seal ring within an annular cavity defined between the ring entrapment surfaces of the two pipe ends.
Preferably, at least a portion of one of the ring entrapment surfaces is angled radially inwardly toward the other ring entrapment surface.
According to a third aspect of the present invention there is provided a pipe for use in a pipe connection assembly according to either of the first or second aspects of the present invention, one or both ends of the pipe comprising a respective torque shoulder, and a respective ring entrapment surface located radially inwardly of the pipe end torque shoulder.
Preferably, the respective torque shoulder of the one or both ends of the pipe tapers inwardly away from the axial extremity of the pipe.
Preferably, the sleeve further comprises a ring- supporting surface extending, and typically axially extending, between the two torque shoulders of the sleeve, and preferably between the radially innermost portions of the two torque shoulders of the sleeve.
Typically, the annular cavity is defined by the ring entrapment surfaces of the two pipe ends, and the ring- supporting surface of the sleeve.
According to a fourth aspect of the present invention there is provided a final pipe end connection component comprising one pipe end and a sleeve in a one piece unit, and a resilient seal ring, for attachment to the pipe end of a pipe in accordance with the third aspect of the invention which forms the last of a series of pipe made up with the pipe connection assembly of either of the first or second aspects of the present invention.
Typically, the resilient seal ring is formed from a corrosion resistant material, thereby forming a corrosion resistant ring.
Preferably, each pipe end further comprises (radially inwards from the radially outermost part of the pipe end) an external screw thread and a sealing surface tapering inwardly towards the axial extremity of the pipe.
Preferably, the sleeve further comprises (radially outwards from the radially innermost part of the sleeve) the torque shoulder tapering outwardly away from the respective end of the sleeve, a sealing surface tapering outwardly towards the respective end of the sleeve, and an internal screw thread.
Typically, the ring entrapment surface of each pipe end is a ring entrapment shoulder, and preferably, the ring entrapment shoulder tapers inwardly towards the axial extremity of the pipe.
The ring supporting surface of the sleeve is preferably cylindrical and concentric with the longitudinal axis of the sleeve.
The ring preferably has a cross-sectional shape in its uncompressed state which substantially matches the trapezoidal shape of the annular cavity defined between the respective ring entrapment shoulders of the two mutually opposing pipe ends, and the ring supporting surface of the sleeve, the ring preferably having cross-sectional dimensions causing it to be an interference fit with this annular cavity whereby the ring is compressed in the made-up assembly.
Embodiments of the invention will now be described by way of example, with reference to the accompanying drawings wherein Fig.l is a fragmentary cross-section in a longitudinal/radial plane of a first embodiment of pipe end; Fig.2 is a fragmentary cross-section in a longitudinal/radial plane of a first embodiment of pipe connection assembly, incorporating the pipe end of Fig.1; Fig.3 is a fragmentary cross-section in a longitudinal/radial plane of a second embodiment of pipe end; and Fig.4 is a fragmentary cross-section in a longitudinal/radial plane of a second embodiment of pipe connection assembly, incorporating the pipe end of Fig. 3.
Referring first to Fig.1, this shows a fragment of pipe end 10 in cross-section, taken in a radial plane including the longitudinal axis of the pipe (not shown in Fig.1). The part of the pipe end 10 which is the interior of the pipe (the rest of which is omitted from Fig.1) is at the bottom of Fig.l, while the exterior of the pipe is at the top of Fig.l. The axial extremity
of the pipe of which the pipe end 10 is a part is at the right of Fig.1, while the remainder of the pipe continues leftwards of Fig.1 to the other axial extremity (which is either identical to the Fig.1 end for an identical connection, or a differently dimensioned but otherwise identically formed connection for a similar connection to a larger or smaller pipe, or entirely different for a different form of connection to a different kind of pipe and/or to plant). The dimension 12 denotes the nominal wall thickness of the pipe (ie the radial thickness of the pipe wall).
The radially outermost part of the pipe end 10 is formed with an external screw thread 14 (schematically and incompletely depicted in Fig.1).
Radially inwards of the thread 14 and axially towards the axial extremity of the pipe (at the right of Fig.1) is a sealing surface 16 which has a shallow conical taper converged radially inwards and axially towards the adjacent axial extremity of the pipe. The sealing surface 16 is intended to form part of a metal-to-metal seal in a pipe connection involving the pipe end 10, as will subsequently be explained with reference to Fig.2.
Radially inwards of the sealing surface 16 is a conically tapered torque shoulder 18 which converges radially inwards and axially away from the adjacent axial extremity of the pipe. The sealing surface 16 and the torque shoulder 18 are mutually linked by a rounded transition 20.
In a conventional VAM connector, the conical surface presented by the torque shoulder 18 would continue radially inwards at the same conicity until it
intersected the radially inner surface of the pipe wall. However, in accordance with one aspect of the present invention, the radially innermost part of the conical torque shoulder in a VAM connector is modified as shown in Fig.l by the provision of an oppositely tapered ring entrapment shoulder 22 whose function will subsequently be detailed with reference to Fig.2. The cone angle of the ring entrapment shoulder 22 is preferably about the same as the cone angle of the torque shoulder 18, but the ring entrapment shoulder 22 converges radially inwards and axially towards the adjacent axial extremity of the pipe (ie oppositely to the taper of the torque shoulder 18). The radial extent 23 of the ring entrapment shoulder 22 is preferably about 25% (one quarter) of the pipe wall thickness 12.
The inside surface 24 of the pipe, including the pipe end 10, is coated with a layer 26 of corrosion- resistant material which may, for example, be any suitable polymer and may be self-reinforced by being integrally mixed with glass fibres. The pipewall- coating layer 26 is extended around onto the ring entrapment shoulder 22 as a liner extension 28 which partly covers the shoulder 22 from its radially innermost portion radially outwards towards but not as far as the junction of the shoulder 22 with the torque shoulder 18.
Referring now to Fig.2, this shows a fragment of pipe connection 100 in cross-section, taken in a radial plane including the common longitudinal axis (not shown in Fig.2) of the connection and the two adjacent pipes mutually conjoined thereby. The connection 100 includes two pipe ends, 10A and lOB respectively. The pipe end l0A is identical to the pipe end 10 previously
described with reference to Fig.1 (though somewhat less of the pipe end 10A is shown in Fig.2), while the pipe end lOB is a mirror image of the pipe end 10A (as viewed in Fig.2) but the pipe ends 10A and lOB are mutually identical in all other respects. Parts of the pipe ends 10A and lOB which correspond to previously described parts of the pipe end 10 are given the same reference numeral together with a suffix "A" or "B" as appropriate.
The connection 100 further comprises a sleeve 102 which is externally cylindrical and internally shaped to be complementary to the pipe ends 10A and lOB, except that the sleeve 102 lacks a part complementary to the ring entrapment shoulders 22A and 22B. Not shown in Fig.2 is an internal thread at or near each end of the sleeve 102 and into which the pipe ends 10A and lOB are screwed by means of their respective external screw threads 14A, 14B (not shown in Fig.2). Radially and axially inwards from these internal threads, the sleeve 102 has tapered sealing surfaces 104 which are complementary to the pipe end sealing surfaces 16A and 16B. The sleeve surfaces 104 make metal-to-metal seals with the pipe end surfaces 16A and 16B in the made-up pipe connection 100, as in a conventional VAM connector. Radially and axially inwards from the sealing surfaces 104 the sleeve 102 further comprises torque shoulders 106 which are complementary to the pipe end torque shoulders 18A and 18B, again as in a conventional VAM connector.
Radially and axially inwards of the sleeve torque shoulders 106, the sleeve 102 departs from the equivalent sleeve (not shown) of a conventional VAM connection by being formed with a cylindrical ring- supporting surface 108 which extends axially between
the radially innermost edges of the two sleeve torque shoulders 106. (In a conventional VAM sleeve, the equivalent of the surface 108 would have a much lower radius, such as to extend radially inwards to be substantially flush with the pipe wall).
The pipe connection 100 further comprises a ring 110 of corrosion-resistant material also having suitable mechanical properties such as strength, elasticity, and creep resistance. By way of example, a suitable material for the ring 110 is PTFE (polytetrafluoroethylene) self-reinforced by being integrally mixed with glass fibres. As shown in Fig.2, the ring 110 is trapeziform in cross-section to fit tightly into the trapezoidal annulus defined axially between the opposing ring-entrapment shoulders 22A and 22B, and radially inwards of the ring-supporting surface 108. The dimensions of the unconfined ring 110 (ie as a free component not made up into a connection 100) are preferably marginally larger than the confined ring as illustrated such that the ring 110 is an interference fit within the trapezoidal annulus and such that the ring 110 is compressed by the connection 100 being made up and tightened.
The ring 110 (of corrosion-resistant material) protects the sleeve 102 against contact with substances carried within the pipes and which may be corrosive. The pipewall-coating layers 26A and 26B of corrosion- resistant material likewise protect the pipe bores, and the overlap of the liner extensions 28A and 28B with the ring 110 provides continuity of protection against corrosion across the axial width of the made-up pipe connection 100.
The pipe ends and pipeline connection assembly of
Figs.l and 2 thus provide interconnected pipes which have a corrosion-resistant interior that is free of gaps or interruptions that would otherwise expose the metal of the pipe ends and/or connector sleeve to possible corrosion.
Referring now to Fig.3, this shows a modified form 210 of the pipe end 10 of Fig.l. The metallic part of the pipe end 210 is essentially the same in form as the pipe end 10, though it may have an overall size that is greater or smaller (according to required pipe capacity). The liner 26 which was directly applied to the inside surface 24 of the pipe in the pipe end 10 (Fig.l) is replaced in Fig.3 by a liner 226 which is adhered to the inside surface by means of a grout layer 227. A suitable material for the liner 226 is GRE (glass-reinforced epoxy), ie a pre-cast tube of epoxy resin self-reinforced by admixing a suitable proportion of glass fibres with the liquid epoxy prior to hardening thereof. The pipe end 210 is further modified with respect to the pipe end arrangement of Fig.l in that the liner extension 28 is replaced by a flanged annulus 228 which is conveniently formed of fibreglass-reinforced plastics material.
Fig.4 shows a pipe connection 300 which is the same as the pipe connection 100 of Fig.2 except that the pipe ends 10A and 10B of the Fig.2 arrangement are replaced in Fig.4 by pipe ends 210A and 210B which are respectively identical and mirror image versions of the pipe end 210 of Fig.3.
Whilst it is most preferred that the ring 110 is trapeziform in cross-section to fit tightly into the trapezoidal annulus defined axially between the opposing ring-entrapment shoulders 22A and 22B, and
radially inwards of the ring-supporting surface 108, other cross-sectional forms of the ring 110 may be required in order to fit differingly formed ring- entrapment shoulders 22A and 22B. For instance, it is possible that ring-supporting surface 108 may not extend radially inwardly to the extent shown in Fig.2 or Fig.4, that is the ring-supporting surface 108 has a greater radius than that shown in Fig.2 or Fig.4. In this scenario, the ring 110 may have a greater outer radius than that shown in Fig.2 or Fig.4, and thus may encroach part-way up the pipe end torque shoulders 18, and thus have a hexagonal cross-section. In this scenario, it is also possible that the outer radius of the ring 110 does not make contact with the ring- supporting surface 108, that is there is a gap between the outer radius of the ring 110 and the ring- supporting surface 108, and ring-supporting surface 108 will not in fact support the ring 110, but will be defined as the inner radius 108 of the sleeve 102. The ring 110 will therefore be trapped in the made-up pipe connection 100 by the hexagonal form of the ring 110.
For the final pipe of a series of pipes made up with the pipe connection assembly of the present invention, there may be a final pipe end connection component (not shown). The final pipe end connection component may have either a through bore, or a closed bore in order to seal the end pipe. This component will comprise one piece of metal, typically steel, and will, if it has a bore, comprise the sleeve 102 and one of the pipe-ends 10A or 10B all in one component. In order to make-up the final end pipe connection, the ring 110 is inserted into the component and seats against the equivalent ring-supporting surface 108 and the equivalent ring- entrapment shoulder 28A or 28B for the component. The final end pipe-end 10A or lOB is then inserted into and
torqued against the component until the desired level of torque is reached, as in the made-up pipe connection.
Reference has been made above to protection of pipes, pipe ends, and pipe connectors against corrosion by means of lining systems which are gap-free and effectively continuous. Lining materials and ring components may be substituted which have additional or alternative properties, eg flow improvement. Other modifications and variations of the above-described embodiments can be adopted without departing from the scope of the invention.
Next Patent: SEAL FOR A PIPE JOINT AND SLEEVE FOR CONNECTING TWO PIPE PARTS