Friday, 18 April 2014
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An earthquake can result in natural gas escaping through ruptured pipes. Such incidents could potentially lead to fires and explosions following an earthquake. This was experienced in several earthquake events. By having a seismic gas shutoff valve, the valve will automatically shutoff the gas supply to the building during a sizable earthquake to prevent gas escaping from the incoming gas line to any structure.

These valves are earthquake activated gas shut-off valves. In the event of an earthquake the valve will be closed automatically to prevent gas flow into a structure where earthquake damage may have occurred.

Without having this valve during an earthquake the gas pipes could rupture and uncontrolled gas can flow into the structure finding its way to any common ignition sources. Gas could be easily ignited, so a fire and an explosion will occur resulting in severe damage. By installing these valves the potential risk will be reduced for fire or explosion due to the release of gas into a structure.

These valves are working without any source of internal or external electrical power. It is designed to remain closed until manually reset. The valves are intended to be mounted in the gas line upstream or downstream of the gas-line pressure regulator.

Our valves consist of a swing check valve arrangement with an acceleration sensitive triggering mechanism. The trip mechanism consists of a steel ball resting on a tapered cup-shaped support. The horizontal motion of an earthquake causes the ball to move from the center of the support. This allows the balls mass to act upon the movable pipe of the trip mechanism, activating the valve and initiating closure. Springs assist the valve flapper to close and gas pressure assists in holding the valve disc in the closed position. The trip mechanism is factory set and sealed.

The maximum working pressure is 4.1 bar for commercial and industrial uses in

different sizes from DN ¾’’ to DN 8‘’.

850: for domestic purposes, maximum working pressure 0,035 bar in sizes 3/4’’ and 1’’
851: for commercial purposes, maximum working pressure 0,48 bar in sizes 1 ¼’’ and 1 1/2’
852: for commercial and industrial purposes, maximum working pressure 4,1 bar in sizes ¾’’ to 8’’

The valves are certificated ASCE 25-97; Listed by UL; CE approved