| 摘要 |
A butterfly valve made of a synthetic resin comprising; a valve casing, a valve plate, a valve shaft connected to said valve plate, pivoted turnably to said valve casing and having one end thereof protruding into an axial cylinder formed to protrude from said valve casing, and a rotary moving member engaged with the outer circumference of said valve shaft turnably and slidably in the axial direction, retarding the rotation of an operation handle shaft and transmitting it to said valve shaft.
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