| 摘要 |
PROBLEM TO BE SOLVED: To prevent a drain pipeline from being clogged and to prevent the water sealing of a trap from being broken by exhausting air when the drain pipeline is made a positive pressure, and sucking air when it is made a negative pressure even in double trap piping. SOLUTION: An exhaust valve element 17 opening or closing an exhaust valve port 7 formed on an exhaust port body 1 opens the exhaust valve port 7 against its tare weight by the positive pressure of the drain pipeline 2. An intake valve port 19 is formed on the exhaust valve element 17. An intake valve element opening or closing the intake valve port 19 of the exhaust valve element 17 opens the intake valve port 19 against the exciting force of a spring 30 by the negative pressure of the drain pipeline 2. The upper peripheral edge section of the exhaust valve element 17 is inclined downward toward the outer periphery. A spiral groove 18 rotating the exhaust valve element 17 with the exhaust air is formed on the outer periphery of the exhaust valve element 17.
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