Patent ID: 8196581

Claim:
A mouthpiece supply valve comprising: a housing having an interior; an inlet valve arranged to selectively admit a respiration gas to the interior of the housing from an inlet tube; an outlet valve arranged to selectively discharge the respiration gas from the interior of the housing to an outlet tube; a mouthpiece connector fluidicly coupled to the interior of the housing; a supply gas regulator operative to selectively admit a pressurized gas to the interior of the housing when a pressure within the interior housing is less than an ambient pressure; an exhaust valve arranged to selectively vent the interior of the housing when the pressure within the interior of the housing is greater than the ambient pressure; an overpressure valve fluidicly interposing the interior of the housing and the exhaust valve; a movable actuator operatively connected to the inlet valve, the outlet valve, and the overpressure valve; and a mode selector arranged to shift the actuator from a first position associated with a first mode to a second position associated with a second mode; wherein, in the first position, the actuator allows operation of the inlet valve and the outlet valve such that the inlet valve opens when a pressure within the inlet tube is greater the pressure within the interior of the housing, the inlet valve shuts when the pressure in the interior of the housing is greater than the pressure within the inlet tube, the outlet valve opens when the pressure in the interior of the housing is greater than a pressure in the outlet tube, and the outlet valve shuts when the pressure in the outlet tube is greater than the pressure in the interior of the housing; wherein, in the first position, the overpressure valve is spring-biased shut; and wherein, in the second position, the actuator is operative to maintain the inlet valve shut, the outlet valve shut, and the overpressure valve substantially open.