METHOD FOR CONNECTING GAS PIPE AND DEVICE USED THEREFOR

摘要

A gas pipe connecting method and a device used for the same are provided to allow for ease of removal of a branch pipe by reliably discharging residual gas from a branch pipe when a main pipe is erroneously perforated. A gas pipe connecting method includes a first step of arranging a branch tee(47) on a main pipe(45) and connecting a branch pipe(48); a second step of arranging a sandwich valve(70) on the branch tee, and discharging gas through a breather valve(56) mounted on the sandwich valve and measuring a gas pressure during perforation of the main pipe; a third step of judging as an abnormality if the gas pressure is not the desired one, isolating a pipe punch, and preparing a stopper plug(90) which shuts off the main pipe and communicating the branch tee and the branch pipe; a fourth step of inserting the stopper plug to the branch tee by using a plugging device(80) such that the main pipe is completely shut off and sealed; a fifth step of injecting safe gas into the branch pipe through a connection path of the stopper plug from an external source by using the breather valve arranged on the sandwich valve and discharging explosive gas remaining in the branch pipe; and a sixth step of removing the branch pipe and sealing the connection portion between the branch pipe and the branch tee after completion of discharge of the explosive residual gas.