Patent ID: 7066175

Claim:
In a pneumatically controlled continuous positive airway pressure apparatus for supplying breathable gas from a pressurized source to an individual's breathing appliance, which appliance has an inlet for receiving the gas and an inhalation/exhalation valve for routing the gas to the individual's lungs and the exhaled air to the atmosphere, the apparatus comprising: a demand valve assembly having a supply inlet port adapted to be fluidly connected to the pressurized source, an outlet port adapted to be fluidly connected to the appliance's inlet, a reference chamber and a control assembly responsive to a pressure differential between a reference chamber pressure and an outlet port pressure for fluidly connecting and disconnecting the inlet port to and from the outlet port; and at least one adjustable back pressure regulator fluidly connected to the pressurized source and the reference chamber for setting the pressure in the reference chamber at a selected level above atmospheric pressure, wherein the demand valve assembly includes a main valve disposed between the inlet and outlet ports, wherein the control assembly causes the main valve to open and fluidly connect the inlet port to the outlet port when the outlet port pressure falls below the pressure in the reference chamber and for causing the main valve to close to fluidly disconnect the inlet from the outlet port when outlet port pressure rises to the pressure in the reference chamber; wherein the control assembly comprises a control valve; and the demand valve assembly includes a pressurized nebulizer outlet and a nebulizer valve responsive to the status of the control valve for fluidly connecting and disconnecting the nebulizer outlet to the inlet port when the control valve is closed and opened, respectively.