| 摘要 |
<p>A valve for use in a fire extinguishing system comprising a valve member 12 with a predetermined area on its inlet side exposed to the inlet pressure to produce a force tending to open the valve a larger area on its opposite, control side exposed to the pressure in a chamber 20 to produce a force tending to close the valve a passageway 32 through the valve member and a one-way valve 38 in the passageway 32 permitting fluid flow only from the inlet side to the control side of the valve member. The chamber 20 is vented to atmosphere when fire sensors 28 are activated, and the inlet pressure lifts the valve member 12 off its seat 10 to open the valve. The one-way valve 38 prevents unintentional opening of the main valve in the event of the temporary loss of inlet pressure. A weak spring 44 may urge the valve member 12 against seat 10. <IMAGE></p> |
