| 摘要 |
PURPOSE:To precisely and surely detect the open or close condition of a valve and as well to make it possible to detect foreign matter bit in, by detecting the position of an indicator needle associated with a valve body, and as well by detecting the contact force between the valve body and a valve seat. CONSTITUTION:When fluid having an excessive flow rate flows into a casing through an inlet port 11 due to a rupture of a pipe connected to the flow inlet port 12 of the casing 10, etc., a valve body 14 advances in the direction of fluid flow overcoming a spring 18. The valve body 14 is made in close contact, at its front end, with a valve seat 15 to close a valve port 16 so that the flow of fluid is inhibited. At this time an indicator needle 23 secured to the outer periphery of the valve body 14 turns on a microswitch 23 to detect the close condition of the valve port 6, and a plurality of pressure sensors 26 detects the contact force between the valve body 14 and the valve seat 15 when both are made into close contact together, thereby the close condition of the valve port is assured. If only a part of the sensors 26 detects the contact force, this does means that foreign matter such as, for example, dust or dirt, is bit between the valve body 14 and the valve seat 15. |
