SELF-CONTAINED BREATHING SYSTEM APPARATUS WITH AUTOMATIC BACK-UP

摘要

The self-contained breathing apparatus for use in a noxious or oxygen-deficient atmosphere with redundant first stage pressure reducers and redundant second stage demand regulators which together serve as an automatic by-pass control in the event of a failure in the closed position of a first stage pressure reducer or a second stage demand regulator. A helmet with a face mask and inflatable helmet adjusting device for sizing the helmet to the user's head, provided impact protection and applying pressure to the back of the head causing the face to come into contact with the face mask resulting in the air-tight enclosure of the user's face in the oral-nasal area of the helmet. An integral pump and valve mechanism located in the helmet and operated by pushing on a bulb with the thumb or forefinger compresses air into a bladder thereby sizing the helmet and forming the air-tight seal of the face mask to the user's face. A combination manually operated pump, suction valve and relief valve permit ambient air to be compressed into the helmet bladder without leakage while excess pressure is discharged by depressing the relief valve on the helmet exterior.