AUTOMATIC APPARATUS FOR EMERGENCY CLOSING OF GAS DUCT AT DAMAGE Russian patent published in 1995 - IPC

FIELD: reinforcement building. SUBSTANCE: upon operational mode a pressure in a gas duct changes slowly. The distributing slide valve 16 is forced by the spring 23 to the body 1, the liquid 3 flows through the annular passage 29 of a throttling device between the cavity 25 and the small reservoir 2 without creating a pressure drop on the piston 25 of a hydraulic damper. Upon damage of the gas duct a pressure inside of it begins to drop sharply. A hydraulic resistance of the annular passage 29 prevents a quick movement of the piston and lowering of an effort of the spring 14, causing a downward displacement of the tray 15 with the distributing slide valve 16. The last brakes the membrane 18, opening an access for gas from the cavity 20 of the flange 19 into the output chamber 22 and to a cavity, controlling a chuting member of the gas duct. Then the shutting member closes, isolating the damaged zone. The throttling annular passage is made of materials with different linear expansion coefficients; that provides constant operations of the automatic apparatus at the same pressure drop rate in the gas duct over winter and summer time periods. The value of those pressure drop rate, that causes operation of the automatic apparatus may be adjusted due to change of a length of the throttling passage. EFFECT: enhanced safety of gas duct operation and lowered loss of gas at damages. 2 cl, 5 dwg