|(XX) 1 | This invention relates to pipe couplings.

[G0i)2j The inventio is concerned with pipe couplings for coupling together pipes which are adapted to convey fluid (usually l iquid ; under high to very high pressures. Many such pipe couplings are known in the an. One set of well known pipe coupl ings are is disclosed in US Patent Specifications Nos 7,086,131 and 7,712,796 both to Gibbs et al assigned to Victaulic Company. In those specifications (which are substantially identical _. ! there is described a mechanical pipe coupling which is deformable and comprises interconnectabie coupling parts that subtend angle of less than 1 80* . When the coupling parts are tightened together, the coupling parts deform to the radiu of curvature of the outer surface of the pipe.

|(KX)3 ^: | According to one aspect of the invention there is provided a ^' coupling tor coupl ing 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 havin (i) an arcuate inside surface of the same radius as the outside surface of the pipe, (ii) a plurality of projection on the inside surface, which In use engage respectively the periphera grooves, and (iii) a radial locating groove between the projections; (b) clamping means for clamping the coupling parts together to- clamp the ends of the pipes, (c) a locating ring partially received within the locating groove and projecting therefrom into the path of the pipes, and id) sealing means, preferably in the form of a pressure assisted seal , preferably comprising, urethane, carried by the locating ring to provide a seal between the ends of the pipes. 10004] According to another aspect of the invention there Is provided the combination of (!) a pair of pipes each having a peripheral groove near its end and (Π) a coupling for coupling together the ends of the pipes in a fluid tight manner, the coupling comprising the combination of (a) a piuraiiiy of coupling, parts each having (i) an arcuate inside surface of the same radius as the outside surfaces of the pipes, iii) a plurality of projections on the inside surface, which projections engage respectively in the peripheral grooves , and (iii) a radial groove (hereinafter referred to as "the locating groove") between the projections (b) clamping means for clamping the coupling parts together to clamp on to the ends of the pipes, c) a locating ring partially received within the locating groove and projecting there. ront into the path the pipes, and (d) sealing means, preferably in the form of a pressure assisted seal , carried by the locating ring providing a seal between the ends of the pipes.

10005] Embodiments of the invention wi ll now be. described- by way of example with reference to the accompanying drawings. 0006) in the drawings; -

Figure 1 is a plan view of coupling for coupling .together two pipes;

Figure 2. is an end view, of the coupimg;

Figure 3 is a perspective view of the coupling;

Figure 4 is a plan view of the top coupling pari;

Figures 5 and 6 are respectively sections on lines 5 - 5 and 6 - 6 of Figure 4;

Figure 7 is an under plan view of the bottom coupling, part;

Figures 8 and 9 are respectively sections on lines 8 - 8 and 9 - 9 of Figure 7;

Figure 10 is an enlarged section on l ine 10 - 10 of Figur ^' ! :

Figure 1 1 rs an enlarged detail of the part of Figure 10 which is circled; Figure 12 is a further enlarged detail of the spacer ring and the pressure assisted seal , with the seal in the rest position;

Figure 13 is a section through a swingabie bolt:

Figure 14 is a section through a pivot pin:

Figure 15 is a side view of a cotter pin:

Figure 36 is a side view of a modified coupling part;

Figure 17 is a detail v ew in the direction of arrow 17 in Figure 16; and

Figure 18 is a perspective view of a coupling for coupling together lower pressure pipes.

(0007 ^' ] Referring now to Figure: ί there is -shown a plan of a coupling 200 for coupling together aligned steel pipes 102 and 104 (see Figure 10) in end to end relationship. The steel pipes .102 and 104 in use convey fluid (norm ll liquid) under high pressure which ^' may be between 1 Ba and 250Bar or more. The pipes 102 and 104. have end faces 106 and 1.08 ^' respectively. Grooves 1 10 and 1.12 accurately located relative to the end faces 1 ^' 06 ^' nd 108 are provided respectively in die pipes 102 and 104. The description of the groove 1 10 and 1 12 w ll he discussed beisw.

[0008 ] The coupling 200 comprises two steel coupling parts ^' 202 and 204. Each coupling part comprises a hemi-Cyiindrica ^' i body 206, On the outside of each coupling part is a peripheral centre rib (202a and 204a) and a number of transverse rib (202b and 204b) . These ribs serve to reinforce the coupling parts.

[00091 The coupling part 202 (see Figures 7 to 9) which for convenience is called "the bottom coupling part") has three spaced flat lugs 10 projecting from one- end thereof and ^" two annular lugs 212 projecting- rom the other end thereof. There are- aligned bores 214 in rhc flat lugs 210, The centre open ngs 2 16 of the annular l ugs 212 are aligned.

[0010! The coupling pari 204 (see Figures 4 to called for convenience "the top coupl ing par ") has three spaced tlai lu s 220 projecting from one end thereof and two annular lugs 222 projecting from the other sid thereof. The centre openings 224 of the annular lugs 222 are aligned. The annular lugs 2 12 and 222 of the two coupling parts are interspersed (as best shown in F igure 3) with ihe openings 216 and 224 al igned . The fiat lugs 220 will lie above the lugs 210 when the coupling parts 202 and 204 are in the closed position. i 00 H I Each coupling part. 202 and 204 has an inner surface 226 which is of hems-cylindrical section and which subtends an angle of 180 ^* ' at the centre thereof. The radius- of th is surface 226 is the same as a radius of the outer surface of the pipes 102 and 104. When the coupling pans of 202 and 204 are placed together as wi ll be described below and as shown in Figure 3. the inner surfaces 226 will butt tightly on to the outside surfaces of the pipes 102 and 104. The upper surfaces 228 of the bottom coupling part (apart from the circular lugs) fie in a plane close to-normal to the axis 228 of the coupl ing part 202 , The lower surfaces 230 of the top coupling part 204 (apart from the circular lugs) lie in a plane close to normal to the axis 230 of the coupl ing par 204. Thus, the fiat lugs 210 and 220 will lie in close face to face relationship but will be spaced by a small distance apart i.e. of the order of a couple of mill imetres.

[0012] Midway along the length of the inner surface 226 of each coupling pan 202 and 204 is a deep henri- cylindrical groove 232 (hereinafter called "the locating groove" ). On either side of and spaced from the locating groove 232 is a projecting rim 234. tiach rim 234 is, in section, in the shape ^' of the frustum of an isosceles triangle with a cone ^· angle .of 40". it is 9 mm wide at the base, 6,8 mm wide at the upper end and its height is 3 mm, The grooves ! 10 and 1 12 in the pipes are of nearly complementary shape and size so that the rims. 234 can fit. tightly therein in use with a small space of about 1 millimetre between the surfaces, remote from the locating groove 232.

[0013 ] Fitting into the locating groove 232 is a steel locating ring 236 (see

Figures 10 .and 1 1 }. The locating ring 236 is generally channel shape wit an outside body 238 thai fits into the deepest pari of the locating groove 232, the locating ring having a 0. 1mm space between the top coupling and a 0. I mm space between the bottom coupling. The ring 236 further has two inwardly directed flanges 240 which extend oat of the- locating groove 232 almost, as high as the projecting rims 234 , A pressure assisted seal 242 made of rcti ane is. carried by the locating ring 236. it comprises a body 243 which fits, tightly between the flanges 240 and a pair of arms 244 which project beyond the sides 246 of the flanges 240. The outside surfaces 248 of the arms 244 at about 3 mm beyond the flange 240 are incl ined outwardly by 10° so that the spacing between the ends of the.- arms 244 is 1.5 mm greater than the width of the locating groove 232. A substantially parabolic recess 250 is provided at the i nside of the seal 342 having a pair of straight surfaces 252 joined by a large arcuate centra! surface 254 a its base. 0014] A pivot pin 256 (see Fi ures. 3 and 14} passes through the aligned, openings 2 1.6 and 224 of the cylindrical lugs 212 and 222. The pivot pin 256 has a head 257 with an hexagonal socket 258 at one end and a nut 260 threaded on to the other end to hold it in. place. The locking nut 260 acts through a washer 261 against the side of the annular lug 222 at the edge of the part 204 to hold the pin 256 in position but to allow the coupling parts to be able to pivot about the pin 256. The two coupling parts 202 and 204 can pivot about the pivot pin 256 from a. closed position as shown hi Figure 3 and an open position in which the surfaces 228 and 230 can be substantially ^■ aligned.

|0015] A holding pin 262 is provided. It is similar to the pin 256 having a head 264 with a hexagonal socket 265 and a locking nut 266 re!easably engaging, the other end through a washer 267 to hold it in position. The holding pin 262 passes through aligned botes 214 in the fiat lugs 210. Two swingable bolts 268 are provided located respectively in the spaces between lugs 210 and 220. Each bolt 268 has an annular lower end 269 through which ihe holding pi 262 passes enabl ing; the bolt 268 to swing about ihe pin 262. Each bolt 268 has a shank 270 on to which a nut 272 Is threaded. A locking or cotter pin 274 passes through a cross bore 276 at ihe end of the shank 270 to act as a stop device preventing the nut 272 being, removed from the boh 268. The nut 272 can be screwed from a locking position, which it acts throug a washer 277 on the upper surfaces 278 of me flat lugs 22.0 of the top coupling pan 204 to force the coupling, parts 202 and 204 into the closed position, and an open position butting against the cotter pin 274. When the nuts 272 are in open position they will be sufficiently -far from the upper surfaces 278 of the lugs 228 that the swingable bolts 268 can be -swung from their vertical position to a position at a 1 0° thereto to enable the coupl ing parts 202 and 204 to be able to swing relative: to one another into the open position.

|00{6 _. | The coupling 200 is applied to the pipe ends 1.02 and 104 as follows. The nuts 272 are unwound until they engage the cotter pins 274. The bolts 268 are now swung about the holding pin 262 until they are free of the flat lugs 220 of the upper coupling part 204. The upper -coupling part 204 is now pivoted about the pivot phi 256 so thai the bottom coupling part 202 can be applied to the under side of one (102) of the pipes. -At this stage the locating ring 236 will have remained in the locating groove 232 of the bottom coupling part 202. The coupling part 202 is manoeuvred until the locating ring 236 btuts against the end of the pipe 102. At this point the rim 234 is above the groove 1 10 in the pipe 102 and coupling part 202 is pushed so that the rim 234 enters the groove 110. The second pipe 1 12 is now placed on the bottom coupl ing part 202 on the oilier side of the locating groove 232 until its end face 108 engages the locating ring 236 and the groove 112 will fit on to the rim 234, The top coupl ing part 204 is now swung on the pivot pin 256 until it engages first the locating ring 236 and then the bottom coupling part 20.2 with the rims 234 enga ing in the grooves 1 10. nd 1 12 in the pipes 102 and 104. Hand pressure is applied between the coupling parts 202 and 204 and the pipes so that the rims 234 engage fully in the grooves 1 1 and 1 12. The pivotal holts 26S are. now swung upwardly so that the nuts 272 are above the upper surfaces 278 of the fiat lugs 220. The nuts 272 are now tightened and the faces 228 and 230 of the two coupling parts 202 and 204 are pressed flat against each together, it will be noted that in this position, the arms 244 of the pressure assisted seal 242 will be touch ing the end faces 106 and 108 of the pipes 102 and 104. The pipes 102 and 104 will now be able to accommodate liquid at high pressure. It will be understood that the liquid will act against the arms- 244 of the pressure assisted seal 242 forcing them outwardly to improve and maintain the seal between the pipes. jO017| The coupling parts 202 and 204 are made to very tight tolerances and thus are extremely accurate. Similarly, -great care is taken in locating and turning the grooves 1 10 and 1 12 in the pipes again to very tight tolerances.

I ^' OOl Hf We have found that the coupl ing can secure together pipes containing liquid at a very high pressure with no leakage. I one experiment, the pipes having the outside diameters of 1 14,3 mm were subjected to liquid ηα ατ a pressure of 300 bar and the connection between pipes held firmly in position with no leakage. 10019] Referring now to Figures 16 and 17 there is shown a detail of a modified coupling 300 of the invention. The inner surface 302 of each coupling part (only a detail of part 304 being shown) is formed ^' with a triangular section thread 306. The crests 308 of the thread 306 are pointed. The base 310 of the thread is flat and about one millimetre wide. The crests 308 lie on a semi-circle of the same radius as the pipes 1 3 and. 104. The depth of the thread 306 is 1 millimetre.

|QO20] I have found that when the coupling is tightened on to the pipes, the crests 308 engage and bite into the surfaces of the pipes. The crests form very shallow indentations into the steel pipes. Th is shows that the coupl ng grips tightly on to the surface of the pipes.

1002 1 j A farther modified coupling 320 intended .to couple together two pipes carrying fluid at -a. lower pressur is show hi Figure 18. This coupl ing 320 is substantially identical to the coupling 200 save that its axial length is less- than ihai of the coupl ing 200. The coupling parts 322 and 324 each comprise two flat lugs 326 and 328. A. holding pin 330 .similar althoug shorter than, the hokiing pin 262, passes through aligned bores 332 in the lugs 326 of the bottom coupling part . A single swingable holt 33 (similar to the swingable bolts 268) is pivOtal iy carried by the pi n 330. A ^' nut 336 acts on the upper surfaces of the logs 328 of the top coupl ing pari through a washer 338, Further the top coupling part has two cyl indrical lug 340. The bottom coupling pan has a single lug 342 located between the lugs 340, Again a pivot pin having a head 346 passes through the bores of the cylindrical lugs 340 and. 342 so that the coupling part 302 and 304 can swing about the pin 346 as described in the first embodiment The coupling 320 has internal rims 348 similar to the rims 234 to engage in the grooves 110 and 1 12 of the pipes, It also has a central locating groove 350 similar to the locating groove 232 and it contains a locating ring and seal (which are not shown in Figure 1.8).

10022] It wi ll be seen that all parts of the coupling (apart, from the locating ring and seal) are non-derachabiy held together before being appl ied to the pipes. Further the locating ring 236 is a relatively tight fit in the locatin groove 232 (the locating ring has a 0. 1 mm space between the top coupling and a 0. ί mm space between the bottom coupling). The seal 242 is a tight fit in ihe locating ring 236. Thus the chances of parts being mislaid or lost are minimised if not el iminated. The operation of fitting the coupling to the pipes is simple and can be relatively easil y .effected: by a .suitably trained operative.

10022] I have found that by having the arms of the pressure assisted seal acting against the ends of the pipes, the chances of the; l iquid escaping between the seal and the pipes Is reduce -and normally eliminated.

[00231 The invention is ^; not limited to the precise: constructional details hereinbefore described and illustrated. For example , the various dimensions may vary. More than one fins may he provided on the coupling on each side of the locating ring to engage correspondin numbers of grooves in the pipes. The outside surfaces of the ^• arms ^' of the pressure assisted seal may be incl ined outwardly by more than ^" I0 ^e -and may be inclined outwardly by about 4.5 ^* .