GB546633A - Improvements relating to apparatus for temporarily closing gas mains and the like with the use of an inflatable stopper bag - Google Patents

Abstract

546,633. Stopping gas mains &c. UNDERPRESSURE ENGINEERING CO., Ltd., and TOWNLEY, A. Jan. 20, 1941, No. 767. [Class 99 (ii)] An inflatable bag 19, Fig. 3, for use in temporarily closing a gas main or other pipe 14 is inserted into position in the pipe through a hole 1 therein from a transfer tube 13 fitted over the hole and adapted to accommodate the bag in an uninflated condition, the tube being sealed against the escape of gas by a removable cap 15 provided with glands 16, 17 through which pass an inflating-tube 18 and a separate manipulating-rod 20 formed with an eye 23 connected to the bag. A detachable extension 21 with handle 22 is provided for attachment to the rod 20. The transfer tube may also be sealed from the main by a flexible rubber valve 24, which may be pulled into the sealing position shown, or lowered therefrom, by a wire or the like 27. In modifications, the manipulating-rod may be tubular with the inflating-tube passing through it, and the cap 15 may be replaced by a sealing-piston attached to the manipulating- rod so that it may be operated up and down the tube 13. Where the sealing-piston is used, the tube may be shut off from the main by a seal of pigskin or the like which is cut away by a cutter on the piston. A pressure gauge may be fitted to the side of the transfer tube. Fig. 1 shows a main 2 with a branch 5 attached in the form of a split-tee 5. The hole 1 is cut in the main by means of a drill 4, after which the branch 5 is closed by an inflatable bag 8 inserted from a lateral transfer tube 10. Another transfer tube similar to the tube 13 and containing the main inflatable bag 19 is then fitted axially within the end of the branch 5 in place of the usual drill housing 6. A sealing-valve may be provided at the inner end of the latter transfer tube, operable by means of a lever.