Method and apparatus for supplying breathable gas in emergency oxygen systems, especially in an aircraft

摘要

In an emergency oxygen supply system of an aircraft equipped with a pressurized cabin, breathable gas is supplied by a gas generator (1) for generating an oxygen-enriched gas either from the ambient air, or from air tapped from the engine, or from fresh water. The generator may also generate practically pure oxygen. A mixed gas is produced in a mixing unit (14) from the breathable gas and oxygen as needed especially in short duration transition periods to meet official regulations. The oxygen partial pressure in the mixed gas is varied or controlled depending on the cabin pressure. The breathable gas is fed in a constant mass flow through an on-board distribution network to the breathing masks connected to the network. Selectable masks for the crew may receive pure oxygen while most other masks for the passengers receive mixed gas having an adequate oxygen content.