Patent ID: 8353292

Claim:
An inhalation valve adapted to be disposed on an inhalation duct of a breathing assistance apparatus to regulate a supply of a respiratory gas from a pressurized respiratory gas source to a patient through the inhalation duct, the inhalation valve comprising: a valve body comprising an orifice configured to connect to the inhalation duct, and a moving element operable to block the orifice in a closed position, and to at least partially free the orifice in an open position, the moving element including a recess for aligning with the orifice to allow the gas from the gas source to pass through to the inhalation duct in use, the recess defining a configuration including: a generally triangular profile corresponding to a proportional operation of the inhalation valve when aligned with the orifice, and a generally rectangular profile corresponding to a wide open operation of the inhalation valve when aligned with the orifice, wherein the inhalation valve is adapted to be controlled by a control unit which is distinct from the pressurized respiratory gas source.