Abstract: An aircraft on-board oxygen generation system having a controller 14 for cycling sieve beds of amolecular sieve-type gas separation system 10, provides product gas having a partial pressure of oxygen that more closely approaches the ideal value at any cabin altitude within the operating range of the aircraft. The controller stores a look-up table of desired product gas oxygen content at various altitude levels within the operating range and displays desired product gas oxygen content at altitudes sensed by an altitude sensor 17 for comparison with delivered product gas oxygen content sensed by oxygen content sensor 19. The controller provides for a range of selectable cycle time and adjusts the cycle time in the sense required to null the difference between displayed and sensed oxygen content of the product gas.

Abstract: Oxygen-enriched breathable gas for breathing by aircrew is delivered by an on-board oxygen generating system 11 utilizing molecular sieve adsorber beds 12. The breathable gas is compressed by a compressor 17 and supplied by way of an appropriately switched two-way valve 25 to a plenum storage tank 30 from which it is withdrawn for breathing by aircrew during normal flight operations. The two-way valve may be switched by electronic control means 15 to connect the compressor with an aircrew seat mounted emergency storage bottle 40 when breathable gas of maximum oxygen concentration is being delivered by the OBOGS and the pressure in the emergency storage bottle is sensed to have fallen below a designated value. This reduces the system servicing requirements and minimizes the size of the system components, in particular the adsorber beds.

Abstract: An on-board oxygen generating system (OBOGS) includes a molecular sieve oxygen generating system (MSOGS), a breathable gas delivery regulator selectively operable to deliver 100 percent MSOGS output gas or air diluted output gas to a user, a back-up storage plenum and control means arranged so that when air diluted delivery gas is selected a portion of 100 percent MSOG output gas is diverted to charge the storage plenum and when 100 percent MSOG output delivery gas is selected diversion to the storage plenum is automatically prevented. The breathable gas delivery regulator includes an injector adapted to induce a flow of air to mix with 100 percent MSOG output gas when air diluted delivery gas is selected.

Abstract: A breathing regulator suitable for regulating aircrew breathing demand for oxygen-enriched air supplied as breathing gas by an aircraft on-board oxygen generating system includes a valve responsive to pneumatic signals from an aircraft mounted, G sensitive valve. The valve throttles passage of gas from a breathing-pressure control chamber to ambient atmosphere so that in high or rapidly increasing G load conditions the pressure in the breathing-pressure control chamber is increased and a positive delivery pressure is provided at the regulator outlet.

Abstract: A molecular sieve type gas separation system capable of delivering oxygen-enriched air by increasing the oxygen content of air fed to the system has control means including a valve arrangement associated with each sieve bed for cyclically subjecting each bed to a charge/adsorption on-stream phase followed by a purge/desorption regeneration phase. During the regeneration phase of each sieve bed the gas pressure in the bed at least substantially equals the ambient atmospheric pressure or a pressure related thereto such as the ambient pressure of an outlet to which the oxygen-enriched air is being delivered and, for a predetermined range of outlet ambient pressure, the overall cycle time and the relative durations of the phases are fixed at values such that the oxygen content of air delivered by the system remains within physiologically acceptable limits for breathing.

Abstract: In supplying a high volume flow of oxygen-enriched air from a molecular sieve type gas separation system, two sets of molecular sieve beds are coupled in parallel. The beds and of each bed set are cyclically subjected to a charge/adsorption on-stream phase followed by a purge/desorption regeneration phase and are controlled to operate in overlapping sequence with respect to each other. At the same time the corresponding beds are controlled to operate in antiphase relationship to each other.

Abstract: A molecular sieve type gas separation system capable of delivering a product gas of controlled variable composition and being especially useful for the production of oxygen-enriched air as breathable gas for aircrew, has an apparatus for controlling the regeneration of the or each sieve bed so as to achieve delivery of the product gas with a constituent concentration which is variably selectable within a predetermined range of values.