| 摘要 |
PROBLEM TO BE SOLVED: To shorten the working time and easily connect a branch pipe by forming a branch opening communicated with the branch pipe in a branch position of a main pipe by a drilling means inserted in the branch pipe. SOLUTION: When the fusion of a branch saddle 20 to a mainpipe 2 is completed, a bore hole is formed in a center of a branch opening by a centering member inserted in a feeding pipe 1 equivalent to the branch pipe so as to center the connecting position of the feeding pipe 1 to the main pipe 2. In this case, a small-diameter bore hole R1 penetrating through the circumferential walls of the main pipe 2 and the branch saddle 20 are formed. After completing the centering, an airtight test for the feeding pipe 1 is performed by detecting the pressure of gas flowing in the feeding pipe 1 via the formed drilled hole. A drill is used for the drilling member 24 and a branch opening is formed by an electric motor 25 additionally provided to the drilling member 24 with the center position of the drill 24 set to a bore hole R1. The inside of the feeding pipe 1 and the inside of the main pipe 2 are thus communicated with each other.
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