| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an automatic gas pipe closing appliance with a simple mechanical configuration which is easily installed in a gas pipe even below a street etc., and is maintenance-free. SOLUTION: In a shutoff appliance box 1 in the upstream of a broken part, the gas pressure in the upstream of a valve 2 becomes rapidly higher than the gas pressure in the downstream thereof, and the gas pressure by the flow A of the regular gas exceeds the repulsive force of a spring 6 to depress the valve, and the flow A of the regular gas is automatically shut off. After the repair of the gas pipe is completed, the gas pressure in the downstream of the valve 2 is equal to the gas pressure in the upstream after the predetermined time is elapsed based on the gas flow through a gas free-flowing inlet 3, and the position of the valve 2 is automatically returned to the position B of a regular valve from the shut-off condition by the repulsive force of the spring 6. Also in the downstream of the broken part, the valve 2 is pushed up by the back gas flow, and automatically returned after the shutoff and completion of the repair.</p> |
