| 摘要 |
PURPOSE:To enable a coil spring to expand at a high temperature and prevent permanent strain by loosely fitting a movable ring over the valve shaft of a valve body and installing a coil spring made of a shape remembering alloy on the underside of said movable ring, and a buffer spring on the top surface of said ring respectively. CONSTITUTION:A movable ring 10 is loosely fitted elevatably in the middle of the valve shaft 4a of a valve body 4, and a spring 8 made of a shape remembering alloy is installed between the underside of the movable ring 10 and a valve seat member 2 which forms a valve port 3. And, a coiled buffer spring 11, which absorbs the expansion force of the spring 8, is installed between the top surface of the movable ring 10 and a fixed collar part 6 at the top end of the valve shaft 4a. When the inside of a valve main body 1 becomes hot due to a pressing fluid, the spring 8 expands making the valve body 4 rise, to close the valve port 3 with the valve head 4b. When the atmosphere inside the main body 1 reaches a high temperature above 100 deg.C, the expanding force of the spring 8 itself is absorbed by the buffer spring 11 allowing the spring 8 to further expand and, thereby, the permanent strain of the spring 8 can be prevented. |
