PURPOSE: To form a drain pipeline easily at low cost without sealing the outlet of a lateral branch pipeline by extending the tip of a lateral branch pipeline inward of a joint, and forming the water film of drain flowing down in a verti cal drain pipeline.
CONSTITUTION: Even though a water film 6 is formed in a pipe joint 4a by drain 7a flowing down along the wall surface of a vertical pipe 2 on the upper side, the front of an outlet 44a is not closed by the water film 6 since the outlet 44a of a lateral branch pipeline 5a to the vertical pipeline 2 is provided on the inside of the water film 6, and air in the lateral branch pipeline 5a is always communicated with air core in the vertical pipeline 2 as shown by arrow marks. Air pressure in the lateral branch pipeline 5a does not therefore change so as to prevent the escape or the like of sealed water in a trap 8 provided at the plumbing equipment or the like of each house and connected to the lateral branch pipeline 5a. Moreover, since the wall surface of a tubular part 44 is formed into the curved surface, small dirt or the like in the drain 7a flowing down from the upper reaches is prevented from being caught by the tubular part 44 and accumulated. A drain pipeline is formed only by connecting the lateral branch pipe 5 to an end connection 43.
KAGOSHIMA EIICHI
WATANABE MITSUHIRO
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