| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a pilot type opening/closing valve capable of achieving smoothness of a valve closing operation and stabilization of a valve closed state more suitably than a conventional one.SOLUTION: A pilot type opening/closing valve V1 has a partition wall part 4 in which a tip is made to be a first valve seat 41, and regions on the outside and inside of the partition wall part 4 are made to be a primary side flow passage 11 and a secondary side flow passage 12 respectively. It has a step part 43 which is provided at a position lower than the first valve seat 41 out of an inner peripheral surface of the partition wall part 4, and whose inner diameter is made to be small. The step part 43 has a surface annular in a plan view which protrudes from the inner peripheral surface in a lower part vicinity portion of the first valve seat 41 inwardly in a radial direction of the partition wall part 4, and the surface is made to be a second valve seat 42. According to a difference between a primary pressure and a secondary pressure, it can be changed between a state where a diaphragm valve body 2 comes into contact only with the first valve seat 41 and a state where the diaphragm valve body comes into contact with both the first and second valve seats 41, 42.</p> |
