Gas fumigation

摘要

A method and system for fumigating a region with a non-flammable gaseous mixture including phosphine. A sensor (74a-c) senses the concentration of phosphine for atmosphere of the region (44a-c) and a flow controller (38) controls flow to the region (44a-c) in response to the sensed concentration. A recycling passage (42) removes a portion of the atmosphere from the region and returns the atmosphere to create a recycle flow through the region. In addition, a gas mixing system (20) is provided to supply the non flammable mixture by mixing phosphine from a phosphine source (24) and an inert substance from an inert substance source (22). <IMAGE>