| 摘要 |
PURPOSE:To prevent an erroneous closing of a valve port caused by accidental fire and provide a complete seal against a leakage of gas from a valve chamber by a method wherein an operation-sensing part made of a shape memory alloy is arranged, a gas passage is opened with an austenite phase at the operation- sensing part and the gas passage is closed when a martensite phase is generated. CONSTITUTION:An operating member 105a is moved in a direction A by an austenite phase generated under heating of flame from a gas burner 101 caused by an operation-sensing part 100 which is made of a shape memory alloy. with this movement, the operating member pushes a rubber-like resilient film 109, and pushes a valve body 103 fixed to one end of the operating member 105b against a repelling force of the compression spring 107. With this movement, the valve body 103 is moved away from the valve seat 106 to close the gas passage 108a communicating with the gas inlet port 108. The operation-sensing part 100 shows a martensite phase on the accidental fire of the gas burner 101 and when a tension force of the shape memory alloy is lost, the valve body 103 moves under a repelling force of the compression spring 107, abutted against the valve seat 106 to close the gas passage 108a.
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