A PHOSPHINE DISTRIBUTION SYSTEM

Claims

A phosphine distribution system (1) comprises a phosphine gas supply subsystem (10) comprising a phosphine source (12) and a phosphine supply duct (16); an air supply subsystem (20) comprising an air inlet (22), a fan (24) for introducing air into the system (1) through the air inlet (22) and an air supply duct (26); and a mixer (30) connected to each of the phosphine supply duct (16) and air supply duct (26).The mixer (30) is operable to form a phosphine / air mixture having a selected phosphine concentration; a distribution line (40) extending from the mixer (30) supplies the phosphine / air mixture for fumigation dosing when a selectively openable valve (25) is open; a diluent gas supply subsystem (50); and a control system (100) controls the fumigation dosing, including the phosphine dosing in the phosphine supply line (16) to the mixer (30). The control system (100) mandates the supply of diluent gas from the diluent gas supply subsystem (50) to a selected portion of the phosphine distribution system (1) when a predetermined event occurs.