To provide intake/exhaust valves capable of performing air intake of a large amount, breaking vacuum in a rise pipe immediately in response to generation of negative pressure on the upstream side, and preventing counter flow from a branched part.
A casing constituted of a body 5 and a cover 41 is partitioned into upper and lower chambers 3 and 4 by a casing bonnet 11. In the exhaust valve 16, when the water level in the lower chamber is dropped, a float valve element 20 is inclined and separated from an exhaust valve packing 18 to open an exhaust hole 19a and exhaust air in the lower chamber. When negative pressure is generated on the upstream side, a valve element 31 of an intake valve 25 is dropped to open an intake port 14. A valve element 49 of a sub intake valve 45a is dropped, a sub intake port 45 is opened to perform air intake of a large amount.
TAKEDA YUICHI
Kunihiro Daigo
Onishi Ikuko