A system including the method employed, for controlling the flow of a pressurized gas through a variable orifice flow control valve in a pressurized gas conduit system, such as a ventilator, in response to either a desired flow rate/volume input signal, a desired pressure signal or both. With respect...http://www.google.com.au/patents/US5331995?utm_source=gb-gplus-sharePatent US5331995 - Flow control system for medical ventilator
