| 摘要 |
PURPOSE:To provide a shut-off valve which enables sharp reduction of valve operation energy during opening of a valve, by a method wherein an auxiliary valve nozzle, mounted to a valve body, is opened and closed through operation of a valve operating mechanism. CONSTITUTION:When a valve body 40 is opened, with a plunger P pulled up, a second valve body 43 is pulled up against the press force of a second valve body pressing-down spring 43a to open an auxiliary nozzle 42. With a first valve body 41 pulled up, a main valve nozzle 11 is opened to cause flow of gas. A plunger P pulls up the second valve body 43 against the press force of the second valve body pressing-down spring 43a to open the auxiliary nozzle 42. As a result of this constitution, gas can outgo from the upper stream side, i.e., the high pressure gas feed side to the low pressure downstream side through the opened auxiliary nozzle 42. This enables about balance of a gas pressure on the upper stream side with a gas pressure on the downstream side.
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