| 摘要 |
PROBLEM TO BE SOLVED: To provide an existing pipe double closing method and its device capable of performing a safe double closing against an existing pipe for communicating an application range enabling combustible fluid to be flowed and a work range accompanying with fire even if two valves appropriate for the work range are not present.SOLUTION: This invention is a method comprising the steps of [A] fully closing an existing shut-off valve 2 arranged between a work range 1 and an existing pipe 4, discharging combustible fluid from the existing pipe 4; [B] shrinking a pair of flexible balloons 12 and inserting them from the first boss hole 5 in the existing pipe 4;[C] expanding the pair of balloons 12 within the existing pipe 4 with pressurized inert gas, air-tightly partitioning the inner surface of the existing pipe 4 at axially spaced-apart two locations and filling the pressurized inert gas between the two locations; and [D] releasing to the atmosphere or reducing pressure for the second boss hole 6 at the existing shut-off valve with a pair of balloons 12 within the existing pipe.SELECTED DRAWING: Figure 4 |
