To reduce the trouble and cost for backfill by branching an insertion pipe to a new branch pipe in an existing branch pipe so as to eliminate the need of open-cut and backfill earth (road) on the existing pipeline.
The outside diameter of a new branch joint 20 is smaller than the inside diameter of the existing main pipe 12 and a branch socket 32 is projected toward the inside of the new branch joint 20, so that the new branch joint 20 is joined to a position of the exiting main pipe 12 corresponding to the existing branch pipe 14 and the insert pipe 16 is inserted in the existing main pipe 12. A new branch pipe 22 is inserted in the branch socket 32 of the new branch joint 20 through the existing branch pipe 14. Thus, in a part of the existing branch pipe 14, branching can be performed from the insertion pipe 16 through the new branch joint 20 to the new branch pipe 22.
BAI HIDEKI
HARADA TAKATOMO
OKUMURA HIROSHI
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