| 摘要 |
PURPOSE: A branch tee removing method is provided to reduce scattering dust caused by excavation and a pedestrian and vehicle control area as the number of underground holes to be excavated is reduced and a gas supply is not stopped. CONSTITUTION: A branch tee removing method is as follows. An underground hole where a branch tee is installed is excavated so that the branch tee is exposed(S101), A sandwich valve is installed on the top of the branch tee(S102). A plug of the branch tee is removed(S103). A branch tee removing device is installed on the top of the sandwich valve(S104). A stopper of a perforation hole is inserted into the perforation hole by a movable bar, thereby closing the perforation hole(S105). The branch tee removing device is separated from the stopper of the perforation hole and the sandwich valve(S106). Nitrogen is injected inside the branch tee(S107). The branch tee is separated from the main pipe(S108). [Reference numerals] (S101) Underground excavation; (S102) Installing a sandwich valve; (S103) Removing a plug; (S104) Installing a branch tee removing device; (S105) Inserting a bore hole stopper; (S106) Separating the branch tee removing device; (S107) Injecting nitrogen; (S108) Separating a branch tee; (S111) Installing a fitting; (S112) Installing the sandwich valve and the branch tee removing device; (S113) Separating the bore hole stopper; (S114) Installing a plug; (S115) Coupling a coupling cap
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