| 摘要 |
PURPOSE:To eliminate permanent set in a knife edge of a gate seal in time of baking, by forming a metal seal ring and a gate seal operating device with an alloy having a shape memory effect. CONSTITUTION:A seal ring 12 and each of links 19 and 20 are formed with an alloy having a shape memory effect. In time of baking, a valve body 11 grows large in its interval between top and bottom inside a hollow chamber as much as a portion for delta1 due to heat expansion. On the other hand, the seal ring 12 increases in size as much as a portion for delta2 owing to the shape memory effect. Here delta1 and delta2 are selected in advance so as to be equalized. When baking advances, an operating device grows large as much as a portion for delta3 but since these links 19 and 20 function so as to be decreased as much as a portion for delta4 owing to the shape memory effect, vertical size for the operating device or the like keeps up measurements in room temperature in consequence. |
