| 摘要 |
PROBLEM TO BE SOLVED: To prevent abrasion, cracking, and lowering of elastic force in a seal member to provide excellent sealability for a long period. SOLUTION: This valve comprises a valve casing 2, a valve body 35 provided movably inside the valve casing 2 to open and close a discharge port 54, an inflate seal 46 attached to in an outer circumferential part of the valve element 35, and a cylinder 27 for driving the valve element 35. The seal 46 is a hollow body, and has a function inflated by supplying air into a holow part to be pressurized, and deflated by depressurizing the hollow part. When the discharge port 54 is closed, the inflate seal 46 is inflated to contact with a seal part on the discharge port 54 side, so as to seal a space between the discharge port 54 and the valve element 35. When the discharge port 54 is opened, the inflate seal 46 is deflated to be separated from the seal part on the discharge port 54 side, so as to release the sealed condition between the discharge port 54 and the valve body 35.
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