Oxygen Regulator 14800-8DP

1. Description
A. This section contains overhaul and test procedures for the Diluter Demand Autmatic Pressure Breathing Oxygen Regulators< Models 14800-8C, 14800-8D and 14800-8E manufactured by The Aero Corporation, Life Support Products Division, Buffalo, New York. They are designed to fulfill supplemental and protective breathing requirements for a crew member of commercial transports at cabin pressures from sea level to 50,000 feet. The Regulators provide the correct oxygen-air mixture in the corrrect ratio, depending on altitude, and delivers this mixture at the correct oxygen pressure to the mask under inhalation.

2. Operation
A. With the SUPPLY lever in the "0N" position, and the ''100% OXYGEN-NORMAI-OXYGEN" lever in "N0RMAL OXYGEN'' position, oxygen enters the Regulator inlet, flows through its manual supply valve to a chamber provided with a relief valve, which protects against overpressure. When there is sufficient differential pressure across the outer diaphgrarm, the demand valve lever assembly is forced down, opening the demand valve. This pressure differential exists during the users inhalation cycle, creating a reduction in pressure at the Regulator outlet. During periods of flow, the oxygen flows through a venturi located next to the outlet. Here this flow of oxygen is mixed with air that enters through the inlet port in the diluter housing assembly. The addition of air to oxygen is controlled by the "100% 0XYGEN-N0RMAL-0XYGEN" lever and also by the diluter aneroid assembly, which automatically produces a 100 percent oxygen concentration at altitudes above 32,000 feet. A diluter check valve prevents a flow of oxygen out through the diluter housing assembly inlet port. The EMERGENCY-N0RMAL- TEST MASK applies force to a spring which, in turn, through a lever, mechanically loads the outer diaphragm to provide positive pressure at the Regulator outlet. In order to obtain automatic safety pressure and pressure breathing at altitudes above 30,000 feet, the Regulator utilizes a pneumatic device which is actuated by an aneroid at altitudes starting above approximately 27,000 feet. The aneroid exerts force on a diaphragm, lifting a ball valve assembly, which permits oxygen to flow to a diaphragm which, in turn, is pressure-loaded by this volume of oxygen and acts on the demand valve lever to the extent positive pressure is built up at the Regulator outlet as the altitude is increased.