| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas cut-off construction method and a gas cut-off device using bags by which a working area can be narrowed in maintenance of an already arranged pipe line. SOLUTION: Tandem type bags 21, 22 in shrunk condition are inserted from a communication hole into a pipe toward a leakage position X. The bags 21, 22 are moved until the rear end of the second bag 22 is positioned inside of the communication hole. Subsequently, a hose 41 in a reciprocation air pump 4 is connected to a first hose attachment 31c, and air is supplied to the first bag 21 so as to inflate the first bag 21 in the pipe. Then, the hose 41 is connected to a second hose attachment 32c, and the second bag 22 is inflated. This operation is carried out on the upstream and downstream sides, and after the flow of gas is completely cut off, the hose 41 of the pump 4 is connected to a suction hose 25 on either of the upstream side or the downstream side so that residual gas inside a maintenance section is discharged. |
