VALVE

PROBLEM TO BE SOLVED: To simplify an electrical interface and reduce cost by applying the constitution that a stem is extended through a valve so as to have the forward end at a position near a recess formed on the bottom of a valve easing, and a communication passage for connecting sealed space to a flow passage is formed on the stem. SOLUTION: A stem 6 passes through a valve 5, and the forward end thereof is positioned near a recess 2a formed on the bottom of a valve easing 2. Furthermore, a piston fixed to the forward end of the stem 6 is internally coupled to the recess 2a of the valve casing 2, thereby forming sealed space 10 with the recess 2a. In addition, a communication passage for connecting the sealed space 10 to a flow passage 3 is formed on the stem 6. When a valve is closed, the capacity of the sealed space 10 formed between the piston and the bottom recess 2a of the valve easing 2 is reduced, thereby causing liquid contained in the sealed space 10 to flow out toward the flow passage 3 of the valve easing 2 through the communication passage on the stem. As a result, a valve closing operation is retarded.