Fitting

Abstract: A fitting for connection to the end of a pipe lined internally with a compressible lining with which the fitting is to form a seal a portion of which lining extends beyond the end of the pipe, comprises a collar 1 having an internal wall adapted to fit over the end of the pipe 4 and to sleeve the portion 8 of the lining 6 and means 2 adapted to clamp a circumferential portion of the lining 6 to the adjacent internal wall of the collar 1.

Description: This invention relates to a fitting in combination with a pipe lined internally with a compressible lining which protrudes from an end of the pipe. It is well known to extend the life of fluid carrying pipes made of pit, cast, spun or ductile iron and steel by lining them with a resin impregnated fabric hose or with polyethylene or similar type plastic material when the pipes become defunct due to corrosion or fracture or because the joints are leaky. In the case of hoselined pipes it is common practice to replace an end section of the defunct pipe with a new non-defective section of similar diameter to the old pipe before the pipe is lined. This new section of pipe is connected to the remainder of the old pipe and after the pipe has been lined with the hose, means are provided to form a seal between a portion of the lining protruding from the new end of the defunct pipe and the internal wall of the new section of pipe into which section the lining extends. One problem with such a seal is that it is not possible conveniently to test the leak tightness of the seal independently of the remainder of the pipe. DE-A-2 034 185 discloses a combination of the type (hereinafter called the type referred to)in which a fitting is in combination with a compressible lining which protrudes from an end of the pipe, and wherein said fitting comprises a collar provided with a collar flange, said collar being slidably fitted over an external wall of said pipe, a generally cylindrical hollow member extending within the collar and the protruding end of the lining and having an external wall against which the protruding end of the lining is sealingly clamped around the member, said member having a member flange adjacent to said collar to which the flange is clamped using nut and bolt assemblies, said collar flange being adjacent to said member flange, an annular space between the collar and said member and surrounding the member, the protruding end of said lining being exposed to said space, and said space being sealed in a fluid-tight manner from the interior of the lined pipe provided the seal between the member and the lining is fluid-tight. In DE-A-2 034 185 the collar is a thick ring or tube of fibre-glass and resin bonded to the pipe and the member flange is clamped against an end of the collar without any seal being provided between the member flange and the end face. There is a small annular space shown in DE-A-2 034 185 between the collar and the member. Because that space is so small there is a considerable risk that when the fitting is properly clamped together the compressed lining will extend longitudinally at right-angles to the direction of compression and fill the space. Furthermore any space that might exist will be small, making it difficult to find and access thereto is also difficult because of the thickness of the collar, these two difficulties making it almost certain that access to the space from the collar exterior is impossible, particularly, say, in the open within the confined space of the bottom of a trench in which the pipe may be laid. Also the fact that the collar is bonded to the pipe can give rise to messy procedures mixing and applying adhesive and hold up work whilst the bond sets. An object of the invention is to provide a combination of the type referred to in which the leak tightness of the seal between the lining and member can be tested independently of the remainder of the pipe. Another object is to provide a combination of the type referred to in which the collar is attachable to the pipe without the need for bonding. According to the invention a combination of the type referred to is characterised in that said collar has a first external collar flange and a second external collar flange at opposite respective first and second ends of the collar, an attachment flange is an initial sliding fit over said external wall and is attached to the external wall by a compression fitting comprising said first end of said collar and a first sealing gasket of compressible resilient material surrounding said end of the pipe, said first gasket is compressed between the first end of the collar and the attachment flange to form a seal between said collar and said external wall of said pipe, said first collar flange and said attachment flange are secured together using second nut and bolt assemblies, a second sealing gasket clamped between the member flange and the second collar flange using said first mentioned nut and bolt assemblies, and a wall of the collar is penetrable through to said space whereby the content of said space can be observed so that absence from said space of fluid which is the same as the fluid within the lined pipe will signify a fluid-tight seal between the lining and the member. Embodiments of the invention will now be particularly described with reference to the drawings in which:- Figure 1 is a longitudinal view in section of one embodiment of the fitting shown connecting the two adjoining ends of pipes or pipe sections together, Figure 2 is a longitudinal view in section of another embodiment of the fitting also shown connecting the two adjoining ends of pipes or pipe sections together, Figures 3 to 8 show the stages in the assembly of the fitting shown in Figure 2 and Figure 9 shows the fitting of Figure 1 used to blank off the end of a pipe. Referring to Figure 1 the fitting comprises a collar 1 and a clamping means in the form of a member 2 for use with the collar 1. The collar 1 is generally cylindrical in shape and has a first part 3 having an internal wall diameter dimensioned to form a close sliding fit with the external wall 4 of the end of a pipe or pipe section 5 which is lined with a compressible lining 6, the collar 1 having a second part 7 with an internal wall diameter dimensioned to sleeve a part 8 of the lining 6 protruding outwardly from the end of the pipe 5. As shown the internal diameter of the first part 3 of the collar 1 is greater than that of the second part 7 for obvious reasons and a junction in the form of a step 9 is formed where the walls adjoin. Each end of the collar 1 is formed with circular flanges 10 and 11 respectively, the flange 10 permitting one end of the collar 1 to be bolted by nut and bolt assembles 12 to a sliding flange 13 attached by a compression fitting to the outer wall 4 of the pipe 5 and flange 11 permitting the other end of the collar 1 to be bolted by nut and bolt assemblies 14 to inter alia the flanged end 15 of an adjacent pipe or pipe section 16. A flexible circular gasket 17 of rubber or like material is in use as shown positioned around the outer wall 4 of the pipe or pipe section 5, the gasket 17 being compressed between the flanges 10 and 13 to form a seal between the collar 1 and the external wall 4 of the pipe or pipe section 5 upon sufficient tightening of the nut and bolt assemblies 12. In the case of the second part 7 of the collar 1 shown in Figure 1 the internal wall diameter tapers inwardly from its flanged end 11 to the step 9 forming the junction for purposes to be described. However, in the fitting shown in Figure 2 where parts identical to those shown in Figure 1 bear identical reference numbers, the internal wall diameter of the second collar part 7 remains constant. Referring again to Figure 1, the member 2 has a generally cylindrical body 20 which is formed with a flange 21 at one end, the external diameter of the body 20 tapering inwardly from the flange 21 to its other end 22. The external wall of the member 2 is provided with circumferential indentations 23 extending inwardly from the outer surface of the wall. The indentations 23 are arranged as spaced rings along the wall for a purpose to be described. In use of the fitting, the first collar part 3 is fitted over the outer wall 4 of the pipe or pipe section 5 until the wall engages the step 9. The cylindrical body 20 of the member 2 is then inserted into the lining part 8, a compressible flat annular gasket 24 of rubber or like material being first positioned around the outer wall of the body 20 so as in use to be compressed between the flanges 11 and 21. Finally the flanges 11 and 21 are bolted to the pipe flange 15 by means of the nut and bolt assemblies 14, a gasket 25 similar to gasket 24 being positioned between the flanges 15 and 21. The tapers on the outer wall of the body 20 and on the inner wall of the collar part 7 are matched so that on tightening the assemblies 14 the lining portion 8 is compressed between the body 20 and the part 7 so that a seal is formed between the lining and the collar. Corresponding seals are also formed between the flanges 11 and 21 and 21 and 15 by compression of the gaskets 24 and 25. The indentations 23 in the surface of the body 20 enable the body 20 to grip the lining portion 8 when the latter is forced by the body 20 against the collar part 7 to form the seal. In another use of the fitting, the collar 1 can be connected to the pipe 4 before it is lined. The pipe 5 is then lined, part 8 of the lining being allowed to protrude beyond the end of the pipe 5 into the second collar part 7. The cylindrical body 20 of the member 2 is inserted into the lining 8 and the member 2 is connected to the pipe 4 so that the lining part 8 is compressed between the body 20 and the collar part 7. Referring to Figure 2 where parts identical in nature to those in Figure 1 bear identical reference numerals, the collar part 7 in this case mainly serves as a means for connecting the member 2 to the pipe wall 4 but unlike that shown in Figure 1 the collar part 7 in Figure 2 has no taper on its internal wall. In addition a clamping means in the form of a ring-like member 26 is provided to clamp the lining portion 8 to the outer portion of the member body 20. The member 26 is of spring steel or like resilient material and has a frusto-conical form and in use as will subsequently be described is fitted over the lining portion 8 with its narrower diameter end leading. Referring now to Figures 3 to 8, the assembly of the fitting on the pipe wall 4 proceeds as follows. Firstly (Figure 3) the sliding flange 13 is located over the end of the pipe wall 4 and is slid along the wall 4 away from the protruding lining 8 to the position shown. Then the gasket 17 is also located over the pipe wall 4 and pushed towards and against the flange 13. It will be appreciated that a similar operation is necessary in the assembly of the fitting shown in Figure 1. Next (Figure 4) the collar 1 shown in Figure 2 is located around that section of the pipe wall 4 lying between the flange 13 and the end 27 of the pipe 5. This is followed as shown in Figure 5 by the clamping ring 26 being fitted over the lining portion 8 and the body 20 of the member 2 being inserted into the lining portion 8, the gasket 24 being first positioned around the outer wall of the body 20 so as in use to be compressed between the flanges 11 and 21. In order to ensure that the lining portion 8 is securely clamped between the body 20 of the member 2 and the clamping ring 26, the latter is drawn towards the flange 21 of the member 2 by means of a special drawing tool. This comprises two clamping pieces 28 and 29 which when locked together form an annulus for clamping around the ring 2 as shown in Figures 6 and 7. The pieces 28 and 29 are provided with two releasable locking assemblies 30 (only one shown) for locking the pieces together about the ring as shown in Figure 6 and 7. Each locking assembly 30 comprises internally threaded bushes 31 and 32, one located on each piece for engagement and alignment to receive a bolt 33 for locking the pieces together by means of a nut 34 after the bolt 33 has been threaded through the aligned bores of the bushes. The assembly 30 shown in the Figures lies adjacent an outer edge of the pieces 28 and 29 while a corresponding further assembly lies adjacent a diametrically opposite outer edge of the pieces. Each piece 28 and 29 is also provided with through-going apertures 35 and 36 respectively for alignment with corresponding apertures 37 and 38 in the flange 21 of the member 2 to receive drawing bolts 39 and 40 as shown in Figures 6 and 7. Nuts 41 and 42 are then located on the bolts 39 and 40 respectively and by tightening the nuts 41 and 42 against the pieces 28 and 29 the pieces 28 and 29 are drawn towards the flange 21 thereby drawing the clamping ring 26 towards the flange 21 and so compressing the lining portion 8 against the body 20 of the member 2. To equalise the forces on the pieces, there may be two or more drawing bolt/nut assemblies for each piece which are consequently provided with a corresponding number of apertures. After the ring 26 has been drawn over the lining portion 8 in the manner described the pieces 28 and 29 are disassembled and removed so that the position shown at Figure 8 is reached. The collar 1 is then moved towards the flange 21 of the member 2 and is then connected thereto and an adjacent pipe or pipe section 16 in the manner shown in Figure 2. Finally the sliding flange 13 and gasket 17 are moved back towards the flange 10 of the collar 1 and the flange 13 is connected to the flange 10 in the manner shown in Figure 2. Referring to Figure 9 instead of the fitting serving to connect the pipe or pipe section 4 to a further pipe or pipe section as shown in Figures 1 and 2, the fitting may be used to blank off the end of the pipe or pipe section 4 as shown. Here a blanking disc 42 is connected by the nut and bolt assemblies 14 to the flange 21 of the member 3. The fitting may be used to connect a first section of a pipe lined with a hose to an adjoining unlined section. The fitting may also be used to connect a hose-lined pipe to a further pipe. As just described it may also be used to blank off the end of a hoselined pipe. The fitting is suitable for pipes lined with the resin impregnated fabric type of hose, or with polyethylene or similar type plastics materials, such pipes normally being of pit cast, spun or ductile iron and steel, the lining serving to extend the life of an otherwise defunct pipe used for instance as a gas, water or sewage main or for carrying petrochemicals. After the fittings shown in Figures 1 and 2 have been assembled the soundness of the seal between the lining 6 and its clamping member (member 2 in Figure 1 and ring 26 in Figure 2) may be tested independently of the rest of the lined pipe by for instance drilling a hole through the collar part 7 into the spaces 43 in Figure 1 and 44 in Figure 2 between the body 20 of the member 2 and the collar part 7. If the seal is sound no gas will be detected issuing through the hole.

Claims: A fitting in combination with a pipe (5) lined internally with a compressible lining (6) which protrudes (8) from an end of the pipe, said fitting comprising a collar (1) provided with a collar flange (11), said collar being slidably fitted over an external wall (4) of said pipe (5), a generally cylindrical hollow member (2) extending within the collar (1) and the protruding end (8) of the lining (6) and having an external wall against which the protruding end (8) of the lining (6) is sealingly clamped around the member (2), said member (2) having a member flange (21) adjacent to said collar (1) to which the flange (21) is clamped using nut and bolt assemblies (14), said collar flange (11) being adjacent to said member flange (21), an annular space (43, 44) between the collar (1) and said member (2) and surrounding the member (2), the protruding end (8) of said lining being exposed to said space (43, 44) and said space (43, 44) being sealed in a fluid-tight manner from the interior of the lined pipe (5, 6) provided the seal between the member (2) and the lining (6) is fluid tight, the combination being characterised in that said collar (1) has a first external collar flange (10) and a second external collar flange (11) at opposite respective first and second ends of the collar (1), an attachment flange (13) is an initial sliding fit over said external wall (4) and is attached to the external wall (4) by a compression fitting comprising said first end of said collar (1) and a first sealing gasket (17) of compressible resilient material surrounding said end of the pipe (5), said first gasket (17) is compressed between the first end of the collar (1) and the attachment flange (13) to form a seal between said collar (1) and said external wall (4) of said pipe (5), said first collar flange (10) and said attachment flange (13) are secured together using second nut and bolt assemblies (12), a second sealing gasket (24) is clamped between the member flange (21) and the second collar flange (11) using said first mentioned nut and bolt assemblies (14), and a wall (7) of the collar (1) is penetrable through to said space (43, 44) whereby the content of said space (43, 44) can be observed so that absence from said space of fluid which is the same as the fluid within the lined pipe (5,6) will signify a fluid-tight seal between the lining (6) and the member (2). A combination as claimed in Claim 1, characterised in that the member (2) has a generally cylindrical body (20) having an external wall fitting inside the protruding end (8) of the lining (6) and clamping a circumferential potion of that protruding end (8) against a circumferential portion of an internal wall of the collar (1). A combination as claimed in Claim 2, characterised in that the member (2) has an external diameter which tapers inwardly from one end towards an opposite end which is closer to the end of the pipe (5). A combination as claimed in Claim 3, characterised in that the collar (1) has a part (7) which has an internal diameter which tapers inwardly from substantially said second end of the collar, and the protruding end (8) of the lining (6) is clamped against said part (7) by said member (2). A combination as claimed in any one of Claims 1 to 4, characterised in that a or the external wall of the member (2) is provided with a multiplicity of indentations (23) extending inwardly from the outer surface of the said external wall of the member (2). A combination as claimed in Claim 1, characterised in that the protruding end (8) of the lining (6) is clamped against the member (2) by clamping means (26). A combination as claimed in Claim 6, characterised in that the clamping means comprises a ring (26) fitting around a circumferential portion of the lining (6) and clamping it to an external wall of the member (2). A combination as claimed in Claim 7, characterised in that the ring (26) is of a resilient material. A combination as claimed in Claim 7 or claim 8, characterised in that the ring (26) is of a frusto-conical form and the end of the ring (26) which has the smaller diameter lies closest to the end of the pipe (5). A combination as claimed in any one of Claims 7 to 9, characterised in that the member (2) has an external diameter which tapers inwardly from one end towards an opposite end which is closer to the end of the pipe (5). A combination as claimed in any one of Claims 7 to 10, characterised in that an external wall of the member (2) is provided with a multiplicity of indentations (23) extending inwardly from the outer surface of said external wall of the member. A combination as claimed in any one preceding claim, characterised in that the first nut and bolt assemblies (14) are used to secure a second pipe (16) to the member flange (21). A combination as claimed in any one of claims 1 to 5, characterised in that a blanking-off disc (42) is secured to the member flange (21) using the first nut and bolt assemblies (14).

Inventors: HARVEY ANTHONY ARTHUR, HARVEY, ANTHONY ARTHUR
Applicants: BRITISH GAS PLC
Application year: 1991
Main classification: F16L58
IPC codes: F16L55, F16L23, F16L58, F16L21