TSUKISENKAISORYUNYORU EDAKANSETSUZOKUSOCHI

摘要

The invention is designed to avoid the possibility of the discharge from a WC or similar cutting the link between the air in the feeder pipe and the main down pipe. At the point where a feeder pipe (2) joins the main down pipe (9) there is a box section (1) which has a flat top. The bottom of the box consists of a sloping face which is inclined at approximately forty five degrees. The discharge from the sanitary unit (5) flows smoothly and the air in the feeder pipe (8) is at no time cut off from the air in the down pipe (7).