| 摘要 |
<p>The safety cut-off value for use in gas pipe-lines cuts off the flow in the event of fire or explosion. In normal circumstances, the gas flows into the value inlet, past a ball (8) and out of the end nozzle (11). Both ends have screw threads (2,12) to connect into pipe fittings. The ball is held suspended in the value by a tri-metallic spring (6) and a wire circlip (9). The ball will push past the circlip to block the tube in either of the following circumstances: the force of gas on the ball exceeds a value between 4 and 7 Newtons, or the temp. rises to 65 degrees C, causing the spring (6) to expand, pushing the ball through the circlip.</p> |
