WO2017124123A1

WO2017124123A1 - Pipe couplings

Info

Publication number: WO2017124123A1
Application number: PCT/ZA2016/050054
Authority: WO
Inventors: Guy Asher KEDAR
Original assignee: Kedar Guy Asher
Priority date: 2016-01-13
Filing date: 2016-12-21
Publication date: 2017-07-20

Abstract

The combination of (I) a pair of pipes (402) each having a peripheral groove (41 0) near its end and (II) a coupling (400) for coupling together the ends of the pipes (402) in a fluid tight manner, the coupling (400) comprising the combination of (a) a plurality of coupling parts (414, 416) each having (i) an arcuate inside surface (418) of the same radius as the outside surfaces of the pipes (402), (ii) a plurality of projections (422, 424) on the inside surface, which projections engage respectively in the peripheral grooves (410), and (iii) a radial groove (hereinafter referred to as "the locating groove") between the projections (422, 424)) clamping means (510, 512) for clamping the coupling parts (414, 416) together to clamp on to the ends of the pipes (402), (c) a locating ring (426) partially received within the locating groove (428) and projecting therefrom into the path of the pipes (402), and (d) sealing means (434), preferably in the form of a pressure assisted seal, carried by the locating ring (426) providing a seal between the ends of the pipes (402).

Description

PIPE COUPLINGS

[0001 ] This invention relates to pipe couplings.

[0002] The invention is an improvement in or modification of the invention that is described and claimed in Specification WO 2015/061812 (the content of which is also incorporated herein by this reference).

[0003] In the specification of the abovementioned application (hereinafter called "the said specification") there is described a coupling for coupling together the ends of two pipes each having a peripheral groove near its end, the coupling comprising the combination of:-

(a) a plurality of coupling parts each having

(i) an arcuate inside surface of the same or

substantially the same radius as the outside surface of the pipe

(ii) a plurality of projections on the inside surface, which in use engage respectively the peripheral grooves, and

(iii) a radial locating groove between the projections;

(b) clamping means for clamping the coupling parts together to surround the ends of the pipes,

(c) a locating ring received within the locating groove, and

(d) sealing means carried by the locating ring and being

arranged to provide a seal between the ends of the pipes.

[0004] Such a coupling is hereinafter called "a coupling of the kind set forth". [0005] In the coupling of the kind set forth as described in the said specification, the sealing means is in the form of a pressure assisted seal, comprising urethane, carried by the locating ring to provide a seal between the ends of the pipes. The sealing means comprises a body with a pair of slightly outwardly directed side arms with a substantially parabolic recess at the inside having an arcuate central surface ending at a pair of straight surfaces forming the inside surfaces of the arms so that the arms each are narrow triangular shaped parts terminating in an acute angled pointed ends.

[0006] Furthermore in the coupling of the kind set forth as described in the said specification the peripheral grooves are frusto-conical in section with the sides extending outwardly from the base and the projections are

correspondingly shaped.

[0007] I have found that the coupling as described in the said specification is satisfactory in operation, but that some improvements can be made for example so that the coupling can operate when the pipes carry liquid at higher pressures..

[0008] According to one aspect of the invention there is provided a coupling of the kind set forth

characterised in that the sealing means comprises a body having inwardly

directed side surfaces which are in the shape of a frustum of a triangle having an acute cone angle,

in that these inwardly directed surfaces terminate in inwardly directed end portions which join the inwardly directed surfaces at an obtuse angle, and in that the end portions are joined by an inside surface of the body. [0009] The sealing means is preferably a compression seal the inner surface of which is conveniently cylindrical. The seal preferably comprises ultra high molecular polyethylene. The said obtuse angle is preferably between 100° to 120° and preferably 103°.

[0010] According to a further aspect of the invention there is provided the combination of a coupling of the kind set forth with a pair of pipes each having a peripheral groove therein wherein the inner side of each peripheral groove (i.e. the side of the groove remote from the adjacent end of the pipe) is straight and at right angles to the surface of the pipe and the outer side of each groove is inclined upwardly preferably at or about 110° towards the end of the pipe. The projections are preferably of corresponding shape to fit into the grooves. The inner corner of each projection is preferably slightly curved in order locate more easily in the pipe groove.

[0011 ] According to another aspect of the invention there is provided the combination of (I) a pair of pipes each having a peripheral groove near its end and (II) a coupling for coupling together the ends of the pipes in a fluid tight manner, the coupling being substantially as described in the preceding paragraphs.

[0012] Two embodiments of the invention will now be described by way of example with reference to the accompanying drawings.

[0013] In the drawings: -

Figure 1 is a longitudinal section through the combination of the invention

comprising a pair of pipes and a coupling for coupling the pipes;

Figure 2 is an enlarged detail of the part of Figure 1 which is circled; Figure 3 is a transverse section through the sealing means when at rest.

Figure 4 is a detail of Figure 1 showing the sealing means in an operative

position between the ends of two pipes,

Figure 5 is a considerably enlarged view of the part of Figure 4 showing one of the arms of the sealing means in a position in which it seals against the end of one of the pipes,

Figure 6 is a perspective view of coupling for use with pipes carrying liquid at high pressures,

Figure 7 is a view similar to Figure 1 of a coupling pipes carrying liquid at very high pressures,

Figure 8 is a transverse section through the sealing means of the coupling of

Figure 7 when at rest, and

Figure 9 is a detail of Figure 7 showing the sealing means in an operative

position between the ends of two pipes.

[0014] The embodiments of the invention are identical to the coupling described amd illustrated in Figures 1 to 15 of the said specification save as described below and shown in the accompanying drawings.

[0015] Referring now to Figure 1 there is shown a longitudinal section through the combination of a coupling 400 for coupling together a pair of aligned steel pipes 402 and 404 in end to end relationship. The steel pipes 402 and 404 in use convey fluid (normally liquid) under high pressure. The pipes 402 and 404 have end faces 406 and 408 respectively. Grooves 410 and 412 accurately located relative to the end faces 406 and 408 are provided respectively in the pipes 402 and 404. The grooves 410 and 412 will be discussed more fully below. [0016] The coupling 400 comprises two steel coupling parts 414 and 416 which are fully described in the said specification. As described therein each coupling part 414 and 416 has an inner surface 418 which is of hemi-cylindrical section and which subtends an angle of 180° at the centre thereof.

[0017] Midway along the length of the inner surface 418 of each coupling part 414 and 416 is a deep hemi-cylindrical groove 420 (hereinafter called "the locating groove"). On either side of and spaced from the locating groove 420 are a pair of projecting rims 422 and 424 details of which will be described below.

[0018] Fitting into the locating groove 420 is a steel locating ring 426. The locating ring 426 is generally channel shape with a deep central groove 428 and a stepped outside channel 430 thereabout to form two inward flanges 432. The maximum radial height of the locating ring 426 is slightly less than the depth of the locating groove 424 so that the locating ring 426 does not project into the paths of the pipes.

[0019] Sealing means in the form of a pressure assisted seal 434 (shown in the rest position in Figure 3). The seal 434 is made of a resilient material preferably urethane is carried by the locating ring 426. It comprises a body 436 which fits tightly between the flanges 432 and a central outward projection 438 which fits in the central groove 428. The seal 434 has a pair of arms 440 which at rest project beyond the inside surfaces 442 of the flanges 432. The interior and outside surfaces 444 and 446 of the arms 440 are approximately parallel and spaced apart so that the arms are about 2 mm in thickness. The interior surfaces 444 of the arms 440 when at rest are inclined to each other by about 55° as are the outer surfaces 446. Thus the interior and outer surfaces define respectively in section frusta of isosceles triangles each with a small cone angle. The inner ends of the inside surfaces 444 are joined by an arcuate base 446 to form a deep concave substantially parabolic inside surface of the seal body 436. The outside surfaces 446 of the arms 440 project from the sides of the body 436 at about the same level as the lowest portion of the base 446. At the end of each outside surface 446 the arm has an outer end surface 448 which joins to the outside surface 446 at a corner 449. The end surface 448 extends at about 103° to the outside surface 446. The end of the surface 448 is joined by an inner surface 450 extending parallel to the inside surface of the pipes. The corners 449 are located about midway of the width of the flanges 432.

[0020] The groove 410 (best shown in Figure 2) in the pipes 402 will now be described in detail. The groove 412 is identical but of opposite hand. The groove 410 has an inner surface 452 closer to the locating groove 424 and an outer surface 454 remote from the locating groove 424. The outer surface 454 lies on in a plane at right angles to the axis 455 of the pipe 402. The inner surface 452 inclines upwardly towards the locating groove 424 at about 110° to the base 453 of the pipe groove. The projecting rims 422 on the coupling 400 fit closely within the grooves. The inner or coupling edge 456 of each rim 422 is curved (as best shown in Figure 2) in order to locate the rim 422 more easily in the pipe grooves 410 and 412 respectively.

[0021 ] The outside portions 462 of the inner surface 418 on the outside of each projection is provided with triangular crested thread similar to the threads 306 as disclosed and illustrated in the said specification. Such thread is not provided on the inner surface between the projecting rims 422. [0022] The coupling 400 is assembled in much the same way as the coupling of the said specification. The locating ring 426 carrying the seal 434 is inserted into the part of the locating groove 420 of the lower coupling part. The coupling part is applied to the end of one of the pipes (say 402) so that the projecting rim 422. fits into the corresponding groove 410. As these parts are moved together the end of the pipe 402 will engage the corner 449 of the adjacent arm 440 of the seal 434 and will force the arm inwardly. The coupling part is now applied to the other pipe 404 until its recess 412 receives the projecting rim of the coupling 400. Again the end of the pipe engages the adjacent arm of the seal forcing it inwards. The upper coupling part which is pivotally connected to the lower coupling part is swung over receiving the upper part of the locating ring and inserting the rims into the upper parts of the recesses.

[0023] The arms 440 are compressed inwardly so that they are inclined to each other at about 25°.

[0024] It will be seen that the arms 440 biased resiliently outwardly against the pipe ends 406 and 408 corners 449 will seal against the pipe ends. When liquid under pressure is applied to the pipe, liquid will accumulate between the arms 440 facing outwardly to increase and improve the seal between arms 440 and the pipe ends.406 and 408.

[0025] Because the seal 434 is made of resilient material, the corner 449 will be compressed so that there will be a relatively enlarged surface engaging the pipe end as shown in Figure 5. This provides an excellent seal between these parts. Thus the coupling arrangement enables two pipes 402 and 404 containing liquid at a very high pressure, say up to 300 Bar to pass from one pipe to the other without any leakage.

[0026] It will also be seen that because the inner surface of each groove is radial it provides a firm retaining surface to prevent relative movement outwardly by the coupling when under pressure. Furthermore by having the outer surfaces of the recess outwardly inclined, it will be easier to engage the rim into the recess. This is further improved by the curved inner or coupling edge 456.

[0027] It will be appreciated that the locating ring 426 prevents the seal 434 from extruding outward. It also prevents the coupling parts 414 and 416 from squashing the seal 434.

[0028] We have found that the coupling can secure together pipes containing liquid at a very high pressure with no leakage. In one experiment, the pipes having the outside diameters of 114,3 mm were subjected to liquid under a pressure of 300 bar and the connection between pipes held firmly in position with no leakage.

[0029] Reference is now made to Figure 7. There is shown a coupling 500 comprising two steel coupling parts 502 and 504. Each coupling part comprises a hemi-cylindrical body 506. On the outside of each coupling part (but shown only on part 502) is a peripheral centre rib 502a and transverse ribs 502b similar to the ribs 202a and 202b as shown in the drawings of the said specification. At each end of the hemi-cylindrical body the coupling parts 502 and 504 have a pair of outwardly projecting flanges 507 and 508. There are registering bores (not shown) in the adjacent flanges and robust bolts 510 are provided with the bolt heads 512 bearing on the underside of the flanges 506 and nuts 514 engaging the bolts 510 and acting on the upper surface of the flanges 508 to hold the coupling parts 502 and 504 firmly together.

[0030] The coupling 500, apart from the connections formed by the flanges and bolts, is otherwise as described in the said specification. As described therein (and as best shown in Figure 9) each coupling part 502 and 504 has an inner surface 514 which is of hemi-cylindrical section and which subtends an angle of 180° at the centre thereof. Midway along the length of the inner surface 514 of each coupling part 502 and 504 is a deep hemi-cylindrical groove 516 (hereinafter called "the locating groove"). On either side of and spaced from the locating groove 516 are a pair of projecting rims 518 and 520 which are identical to the rims 422 and 424 of the first described embodiment. The rims 518 and 520 fit into grooves 522 and 524 which are identical to the grooves 410 and 412. The rims and grooves will therefore not be described further.

[0031 ] A steel locating ring 526 is received in the locating groove 516. This ring 526 is identical with the locating ring 426 being generally channel shape with a deep central groove 528 and a stepped outside channel 530 thereabout forming two inward flanges 532.

[0032] Sealing means in the form of a compression seal 534 (shown in the rest position in Figure 8). The seal 534 is made of ultrahigh molecular polyethylene. It is carried by the locating ring 526. The seal 534 comprises a body 536 which fits tightly between the flanges 532 and a central outward projection 538 which fits in the central groove 528. The seal body 536 has short radial side surfaces 540 leading to diverging outside, or inwardly directed, surfaces 542 and 544 of which define the frustum of an isosceles triangle with a small cone angle. The outside surface 542 and 544 terminate in short inwardly directed end portions 546 and 548 which join the surfaces 542 and 544 respectively at a corner 550 and 552 having an obtuse angle, preferably of 77° which are the same. The inner ends of the end portions 546 and 548 are joined by a cylindrical inner surface 554 centred on the axis of the seal.

[0033] The coupling 500 is assembled in much the same way as the coupling 416. The locating ring 526 carrying the seal 534 is inserted into the part of the locating groove 516 of the lower coupling part 504. The coupling part 504 is applied to the end of one of the pipes (say 556) so that the projecting rim 518 fits into the corresponding groove 522. As these parts are moved together the end of the pipe 558 will engage the corner 550 of the seal 534 and will force the side of the body 536 arm inwardly. The coupling part 504 is now applied to the other pipe 558 until its recess 524 receives the projecting rim 520 of the coupling 500. Again the end of the pipe 558 engages the adjacent side 544 of the seal 534 forcing it inwards. The upper coupling part 502 is placed over the part 504 inserting the rims 518 and 520 into the upper parts of the grooves 522 and 524. Once these coupling parts 502 and 504 are close together with the inside surfaces of the flanges 507 and 508 lying flat against each other the bores will register. The bolts 510 are passed through the registering bores. The nuts are applied to tighten on the bolts and to clamp the coupling parts 502 and 504 together.

[0034] We have found that the coupling 500 can be used for coupling together pipes carrying liquid under very high pressure of up to 380 Bar without leakage. We have further found that by having the coupling parts connected by bolts, the coupling is more robust than having the coupling parts hingedly connected together.

[0035] The invention is not limited to the precise constructional details hereinbefore described and illustrated. For example, the various dimensions may vary. For example the width of the arms may increase for larger sized couplings. Further the 55° rest position of the arms and the 25° compressed position of the arms may vary as required.

Claims

A coupling for coupling together the ends of two pipes each having a peripheral groove near its end, the coupling comprising the combination of:-

(a) a plurality of coupling parts each having

(i) an arcuate inside surface of the same or substantially the same radius as the outside surface of the pipe

(iii) a radial locating groove between the projections;

(c) a locating ring received within the locating groove, and

(d) sealing means carried by the locating ring and being arranged to provide a seal between the ends of the pipes

characterised in that the sealing means comprises a body having inwardly directed side surfaces which are in the shape of a frustum of a triangle having an acute cone angle,

in that these inwardly directed surfaces terminate in inwardly directed end portions which join the inwardly directed surfaces at an obtuse angle, and

in that the end portions are joined by an inside surface of the body.

A coupling as claimed in claim 1 characterised in that the inside s surface is cylindrical.

A coupling as claimed in claim 1 characterised in that the inside surface is a concave surface. A coupling as claimed in claim 3 characterised in that the concave surface comprises a pair of interior surfaces which are respectively parallel to the outside surfaces.

A coupling as claimed in claim 4 characterised in that the interior surfaces are joined by an arcuate base.

A coupling as claimed in any one of the preceding claims characterised in that the seal comprises urethane.

A coupling as claimed in any one of preceding claims 1 to 5 characterised in that the seal comprises high molecular polyethylene.

A coupling as claimed in any one of the preceding claims characterised in that the each side surface joins the adjacent end portion at an angle of between 60° and 80°.

A coupling as claimed in claim 7 the each side surface joins the adjacent end portion at an angle of 77°.

The combination of a coupling for coupling together the ends of two pipes each having a peripheral groove near its end, the coupling comprising the combination of:-

(a) a plurality of coupling parts each having

(iii) a radial locating groove between the projections; (b) clamping means for clamping the coupling parts together to surround the ends of the pipes,

(c) a locating ring received within the locating groove, and

characterised in that the inner side of each peripheral groove is straight and at right angles to the surface of the pipe and the outer side of each groove is inclined upwardly towards the end of the pipe and in that the projections are of

corresponding shape to fit into the grooves. The combination as claimed in claim 10 characterised in that the outer side of each groove is inclined upwardly at or about 110°. The combination as claimed in claim 10 or 11 characterised in that the inner corner of each projection is slightly curved in order locate more easily in the pipe groove. The combination of (I) a pair of pipes each having a peripheral groove near its end and (II) a coupling for coupling together the ends of the pipes in a fluid tight manner, the coupling being substantially as claimed in any one of claims 1 to 9. The combination of a pair of pipes and a coupling together the ends of the pipes comprising parts arranged and operating substantially as hereinbefore described and as illustrated in Figures 1 to 6 of the drawings. The combination of a pair of pipes and a coupling together the ends of the pipes comprising parts arranged and operating substantially as hereinbefore described and as illustrated in Figures 7, 8 and 9 of the drawings. A coupling comprising parts arranged and operating substantially as hereinbefore described and as illustrated in Figures 1 to 6 of the drawings.

A coupling comprising parts arranged and operating substantially as hereinbefore described and as illustrated in Figures 7, 8 and 9 of the drawings.