Patent ID: 8276584

Claim:
A pneumatically-controlled pneumatic conserving device for breathable gas, the device comprising: a pneumatically-controlled main control valve connected in a user supply line between an inlet for receiving a supply of breathable gas and an outlet for connection to a user, a main valve timer, comprising a main control volume, the pressure within the volume controlling the opening and closing of the main control valve, and a sensing valve for triggering the main valve timer to open the main control valve upon sensing inhalation by the user, and to deliver a pulse of gas of predetermined duration to the outlet, the device being characterised by a pneumatically-operated sensing valve inhibitor for inhibiting operation of the sensing valve, the inhibitor comprising: a sensing delay volume, the pressure within which controls operation of the inhibitor, a cylinder in which is situated a moveable member, the sensing delay volume being to one side of the moveable member; a delay line through which the sensing delay volume is pressurized by gas flow when the main control valve is open, and a delay timer comprising a flow restrictor and vent line connected to the sensing delay volume for controlling the sensing valve inhibitor to inhibit operation of the sensing valve for a predetermined period following the delivery of the pulse of gas to the outlet.