Patent ID: 7087101

Claim:
A method of controlling a gas adsorption apparatus for producing a breathable product gas supply for a main supply system in an aircraft including at least one sieve bed containing molecular sieve bed material, the sieve bed being cyclically operable in a charge mode to adsorb non-product gas from an air supply thereby to increase the concentration of a product gas in a product gas supply line which passes to a product gas supply, and in a vent mode to desorb the adsorbed non-product gas which passes to a non-product gas line, and there being at least one passage to permit a restricted amount only of the product gas supply to pass from the product gas supply line to the bed when operating in the vent mode, and wherein the method includes operating a variable flow device to permit an increased amount of the product gas supply to pass to the bed when operating in the vent mode, under predetermined conditions, wherein at above a threshold altitude a minimum amount of the product gas supply is permitted to flow into the bed when operating in the vent mode, and further including the step of automatically operating the variable flow device in response to an altitude sensor input, to increase or reduce the amount of product gas supply passing to the venting bed at the threshold altitude, depending upon whether the aircraft is climbing or descending.