Patent GB-956196-A (GB)
Title: Apparatus for closing side openings into pipelines
IPC: F16L55/136
Filed: 1962-06-14
Abstract: 956,196. Pressure doors; stopping pipes. T. D. WILLIAMSON Inc. June 14, 1962 [June 15, 1961; June 4, 1962], No. 22996/62. Heading F2P. Apparatus for closing a side opening in a pipe-line comprises in combination a nipple 12 attached to the exterior of the pipe-line and around an opening therein, the nipple having a groove 14 around the interior thereof substantially normal to the flow-way through the nipple, a plug 15 fitting into the flow-way and having a central threaded opening and a passageway for fluid through the plug spaced from the opening, an annular seal 28 around the plug in position to seal between the sides of the plug and the interior of the nipple, retaining members 22 carried by the plug for outward lateral movement into engagement with the groove 14, a control screw 16 engaging the threaded opening in the plug, and means operable by longitudinal travel of the control screw, for concomitantly closing the passageway through the plug and moving the retaining members outward into fully extended position in the groove. As shown, the control screw 16 is provided with a tapered shoulder 17 and a shank 18, the latter being received in a socket 19 of a landing rod 20 and releasably attached to the rod by a pin 21. The plug carries laterallymovable plates 22 which have elongated slots 23 receiving studs 24 screwed into the plug, are freely slidable upon the plug and retained in retracted position by springs 25. Pressure exerted on the landing rod 20 moves the plug downwardly into the nipple 12 and the pressure fluid in the pipe-line flows through the passageways 27, 27a to equalize pressure on opposite sides of the plug. The plug is moved to a position below that of the groove 14 in the nipple and the rod 20 is rotated to move the screw 16 further into the plug so that the shoulder 17 thereof exerts outward pressure on springs 26 sufficient to overcome the tension of the springs 25 and so that the plates 22 are biased outwardly. The plug is then moved upwardly so that the plates 22 snap into the groove 14 and to bring the seal 28 into contact with the inner surface of the nipple. The screw 16 is then screwed downwardly to exert maximum pressure on the springs 26 and to make metal-to-metal contact with the conical surface 32 of the plug thus closing off the passages 27, 27a. In modifications, (a) a plate 43, Fig. 5, carried by studs 44 attached to the body 40 and freely movable thereon towards the body by springs 46, has a bevelled surface 47 which bears on balls 48 to force the latter into the groove 14a of the nipple 12a, (b) pressure members 58, Fig. 11, attached to the laterally-movable plates 22a have bevelled faces which are contacted by the tapered shoulder 17a on the control screw 16a as the latter advances into the plug and to move the plates outwardly against the pressure of springs; the screw 16a has a pin 57 which engages in opposed slots 68 (Fig. 12), in the wall 61 of the landing rod, pins 66 being slidably located in these slots and movable from the gripping position shown to a releasing position. A permanent closure plate may be attached to the nipple.