Self-modulating inert gas fire suppression system

Abstract

A relatively low pressure inert gas hazard suppression system () is provided which is designed to protect a room () or the like from the effects of fire or other hazard. The system () includes a plurality of pressurized inert gas cylinders () each equipped with a valve unit (); each valve unit () is in turn coupled via a conduit () to a delivery manifold (). The respective valve units () are operable to deliver gas from the cylinders () at a generally constant pressure (usually around 10-100 bar) throughout a substantial portion of the time of gas delivery, to thereby provide effective hazard suppression without the need for expensive high-pressure gas handling and distribution hardware and a reduction in room venting area due to lower room over-pressurization. Each valve unit () has a valve body () and a shiftable piston-type sealing member (). Gas pressure from the cylinder () and a spring assembly () biases the memberto the valve open position, this being counterbalanced by gas pressure within equalization and modulation chambers () provided in the valve unit (). When a hazard is detected, the valve units () are actuated by draining of gas from the modulation chambers (), allowing gas flow from the cylinders (). As gas discharge proceeds, gas flows into and out of the modulation chambers () so as to achieve the desired generally constant pressure gas output. Near the end of gas discharge, the spring assembly () becomes predominant and holds the valve unit () open until all gas is discharged.