GB1239451A - - Google Patents

Abstract

1,239,451. Pipe stopping. WALTER SLINGSBY & CO. Ltd. 3 Jan., 1969 [9 Jan., 1968], No. 1234/68. Heading F2P. A device 1 for closing a main gas pipe 30 comprises a tube 2 having a lower externallythreaded part 4 for connection to the main pipe wall, a hollow axially adjustable valve 8, 9 mounted in a closure head 5 of the tube and operable to close off an inlet/outlet opening 10 in the tube wall communicating with a by-pass conduit 17, a rigid air supply pipe 18 axially slidable in the valve having a head 20 for connection to a pump, an inflatable bag stopper 25 connected to the lower end of the supply pipe by flexible tubing 26 and adapted to be housed when deflated in the tube 2, and a deflector plate 29 pendant from the tube part 4 for deflecting the stopper axially into the pipe 30 into a position offset from the tube axis when the stopper is urged out of the tube 2 by pushing down on the supply pipe 18. A main pipe section may be isolated by inserting two of the abovedescribed devices into the pipe at axially spaced locations, Fig. 2 (not shown), the flow being bypassed along the tube 1 of one device, along a common by-pass conduit 17 and along the tube 1 of the other device back to the main pipe. Alternatively four such devices may be used, Fig. 3 (not shown), the outer two by-passing the section to be isolated and the inner two venting said section to atmosphere.