DRAIN PIPE EQUIPMENT

PROBLEM TO BE SOLVED: To prevent the occurrence of fluctuation in pressure in pipe die to a foam plugging phenomenon by separately installing a drain pipe for draining water containing detergent and a drain pipe for draining water containing no detergent, and by connecting a bend at the leg portion of drain pipe for drain water containing detergent to communicate with one end of a vent pipe at a level higher than the bent portion, and connecting the other end of the vent pipe to communicate with the drain pipe for drain water containing no detergent. SOLUTION: A drain pipe A for draining water containing a detergent and a drain pipe B for draining water containing no detergent are installed in parallel in each dwelling unit on each floor level of a building. For the drain pipe A, a confluent pipe 3A to which a riser 2A is connected, a lateral branch pipe 4A is connected and a lateral main pipe 6A is connected to the lower portion of the confluent pipe 3A through a bend 5A at the leg. At the upper side of the bent portion 13 of this bend 5A at the leg portion, a lateral connection 15 is formed, one end of a vent pipe 18 is connected to the lateral connecting portion 15, and other end of the vent pipe 18 is positioned to communicate with the drain pipe B. In this way, even though the foaming of detergent occurs in a pipe from the bend 5A at leg portion of the drain pipe A to the lateral main pipe 6A, the communicating with the drain pipe B can be secured through the vent pipe 18 thereby avoiding the fluctuation in pressure in the drain pipe A.