A safety valve for use in closed systems wherein there is a flow generator delivering oxygen or some other type of breathing gas to a patient. The safety valve of the present invention vents to the open atmosphere in the event that the breathing gas generated by the flow generator diminishes or term...http://www.google.es/patents/US6189532?utm_source=gb-gplus-sharePatente US6189532 - Valve for use in a gas delivery system