Gas supply device

Claim 1

In a device for administering to a patient a mixture of a first gas and at least one second gas in a desired, predetermined ratio between 0 and 100%, the first gas being supplied to the device by a non-pressurized system and the second gas being supplied to the device under pressure; the device including a self-expanding, lung-venting bladder having an inlet through which the gases are introduced into the bladder and an outlet through which the gases are administered to a patient; a check valve disposed in the zone of the bladder inlet for preventing the gases from escaping from the bladder through the bladder inlet; the bladder being adapted to expand for drawing the gases thereinto through the bladder inlet; the bladder being adapted to be compressed for discharging the gases therefrom through the bladder outlet; the improvement comprising a suction valve having a. a housing means defining a chamber having a first wall and a second wall parallel-spaced from said first wall and a circular wall adjoining said first and second walls; b. means defining, in said housing means, a valve outlet disposed in said first wall centrally with respect to said chamber, said valve outlet being connected to said bladder inlet for maintaining communication between said chamber and said bladder inlet; c. means defining, in said housing a suctional intake opening positioned radially outwardly of said valve outlet and being in continuous communication with the non-pressurized system; said bladder, during its expansion, generating a pressure drop from said suctional intake opening to said valve outlet; and d. at least one inlet nozzle extending through said circular wall and supported adjacent said suctional intake opening and being oriented tangentially with respect to said chamber and substantially perpendicular with respect to said valve outlet for injecting said second gas tangentially into said chamber; said inlet nozzle being arranged for controlling, with said second gas, the intake of said first gas by changing said pressure drop in an inverse relationship to the intake of said second gas.