Mouthpiece valve for escape breathing apparatus

A mouthpiece valve for escape breathing apparatus, comprising a tubular valve housing provided in one side with a mouth port and in its opposite side with a vent opening, the housing also having between said port and vent opening an opening for connection to a carbon dioxide removing and oxygen generating canister, a valve seat inside the housing around said port, a valve member in the housing, a spring urging the valve member toward said seat to normally close the valve, a bellows surrounding said valve member and spring and having an open end secured to said housing around said vent opening to thereby continually expose the inside of the bellows to the pressure of liquid in which the valve may be submerged, a mouthpiece connected to the outer end of said port and adapted to be held in the mouth of a user, a ring slidably mounted on said valve housing adjacent the mouthpiece, and means connecting said valve member with the ring for movement therewith, such that the ring is positioned adjacent the mouthpiece and must be moved toward the housing in order to permit the mouthpiece to be held in the mouth with the lips behind the ring, thereby opening the valve, and the valve being adapted to be closed by said spring and liquid pressure inside the bellows when the mouthpiece is removed from the mouth and submerged in a liquid.