Patent ID: 8783251

Claim:
A device for providing ventilatory support of a patient, comprising: a. a inlet chamber having an interior end and an exterior end; b. a valve, said valve including a first actuation area in flow communication with said inlet chamber when said interior end is closed by said valve, said valve including a second actuation area in flow communication with said inlet chamber when said interior end is open, said first actuation area being less than said second actuation area, wherein said valve is configured to open and close by changes in flow pressure applied to said inlet chamber, and wherein the pressure required to open said valve is greater than the pressure required to hold said valve open; c. a biasing member that provides a restorative biasing force on said valve, wherein said valve is normally biased in a position wherein said inlet chamber is closed, and wherein said pressure applied to said inlet chamber opposes said restorative biasing force; d. a primary chamber, said primary chamber in flow communication with said inlet chamber when said interior end is open, and wherein said primary chamber is not in flow communication with said inlet chamber when said interior end is closed, and wherein said primary chamber having internal pressure which opposes said restorative biasing force; e. a secondary chamber, said secondary chamber having an internal pressure which exerts a force on said valve that is in substantially the same direction as said restorative biasing force; f. a equalization conduit, said equalization conduit providing fluid communication between said primary chamber and said secondary chamber; and g. an ambient actuation conduit, said ambient actuation conduit providing fluid communication between said secondary chamber and the ambient environment.