Patent GB-1366999-A (GB)
Title: Apparatus for sealing external surface of a tubular member
Inventor: ARNOLD J F
IPC: F16L7/02
Filed: 1972-01-14
Abstract: 1366999 Pipe engaging sleeve HYDROTECH INTERNATIONAL Inc 14 Jan 1972 [15 Jan 1971] 1918/72 Headings F2G and F2P An apparatus for sealing a portion of the external surface of a tubular member comprises a segmental housing arranged for clamping about the tubular member; at least one resilient packer adapted for mounting about the external surface of the tubular member within the housing, and means connected to said housing for applying axial force to said packer thereby axially compressing and sealingly engaging the packer with the external wall of the tubular member, said means including at least one fluid pressure actuated piston. As shown in Figs. 1 and 3 two segmental halves 10, 12 are pivotally connected by pin 15 engaging lugs 13, 14. A similar arrangement of lugs 16, 17 may be held by a removable pin 18 to secure the device. The resilient packing rings 32, 33 are axially compressed by pistons 42 in cylinders 39, the pressure being evenly applied to collets or slips 23, 24 via divided rings 43, 44. The space between packings 32, 33 is sealed by seals 47, 48 running in grooves 45, 46 in the lower segment 12. A pipe 49 may be provided to permit tools (e.g. cutters) to be lowered down to allow work to be performed on pipe 20. A double acting jack 51 enables the segments to be opened and closed about hinge pin 15. In an alternative embodiment (Fig. 6) (not shown) the pistons (76) are located in cylinders (74) at the ends of the housing and move axially inwardly towards the centre. The slips (70) are arranged to grip the pipe within the central part of the device. Pin (67) (equivalent to pin 18 of the Fig. 1 embodiment) is insertable after the closing of the segments by a piston (84) in a cylinder (82), thereby making the whole device remotely controllable. In a further embodiment (Fig. 7) (not shown) the slips are positioned as shown in Fig. 1 but the piston and cylinder arrangements are situated between the slips and the corresponding resilient packings. In this case the cylinders are separately formed and are axially slidable within the housing so that on admission of pressure fluid the cylinders move towards the slips and the piston moves towards the packings, thereby forcing slips and packings apart. The feed pipes to the cylinders pass through short axial slots in the housing. In a final embodiment (Figs. 8 and 9) only one packing and piston and cylinder arrangement is used, the packing being placed to cover a defect in the pipe so as to be seated over the defect after axial compression. No slips are used and the cylinders are formed by bores 117 in one end wall of the housing. The pistons 122 bear on half rings 115 contained in the segments, each half ring being provided with a tapped hole 116 to take a screw 123 inserted through hole 124. This prevents movement of the rings 115 and pistons 122 until the device is correctly positioned. The device may be used as a temporary or permanent pipe repair or as a device for the introduction of tools to a pipeline. If the repair is permanent the pressure fluid for actuating the pistons may take the form of a hardenable fluid (e.g. an epoxy resin). Packings.-The packings may take the form of a plurality of resilient rings, each ring having a radial cut to allow it to be passed over a pipe to be sealed and the radial cuts subsequently being arranged so that adjacent cuts do not coincide. Alternatively a packing may be as shown in Fig. 1 at 33 and be formed with a plurality of interengaging teeth which interlock after the packing has been passed round the pipe.