Normalair-garrett (holdings) Limited

Robin H Searle

Michael W Harral

A system and apparatus are disclosed for providing oxygen-rich gas for breathing by aircrew and passengers of commercial passenger aircraft. Oxygen-rich gas output by molecular sieve concentrator apparatus 11 is delivered by way of a compressor 17 and a priority valve 24 to a flight crew gas storage cylinder 22 and passenger gas storage cylinders 23. An electronic control unit (ECU) 38 controls cycling of the concentrator apparatus 11 in obtainment of gas enriched with oxygen to at least 90%. The ECU is connected for receiving signals from a monitor 35 which senses the content of oxygen in gas delivered by the concentrator apparatus. The ECU receives signals from pressure sensors 42 and 43 in the cylinders 22 and 23 to initiate start up of the system when the content of these cylinders is sensed to have fallen below a predetermined value. The ECU is connected to switch the priority valve for preferential charging of the crew cylinder when both sets of cylinders require charging. The ECU is further connected for opening a vent valve 46 whereby on start-up of the system, gas delivered by the concentrator apparatus is vented to ambient until the oxygen concentration is sensed to be 90% or more. The system reduces the requirement for ground servicing and weight of oxygen gas storage cylinders carried by present day passenger carrying aircraft. Also, it enables the number of cylinders to be kept at a minimum in meeting the requirements for emergency oxygen on new air routes which are now being developed.

Oxygen-rich gas breathing systems for passenger carrying aircraft

A two stage fluid compressor is operated by a pneumatically operated relay valve controlled by a fluidic switching device in which switching pulses of pressurized control air are obtained automatically on movement of a compression piston in one of the compression stages.

Fluid compressors

A fluid compressor includes a plurality of compression stages each operated sequentially by drive means comprising a pneumatically operated drive piston operating in a drive cylinder. Several embodiments are described and illustrated having different forms of control means and drive and sequencing means for the drive pistons.

Apparatus for generating oxygen enriched air from a flow of ram air supplied to a hydraulically driven air compressor 10 by way of an inlet 11. After pressure intensification the air is delivered to a gas concentrator unit 50 (shown in FIG. 2) through a supply line 90. Molecular sieve beds provided by the concentrator unit 50 are cycled through charge/adsorption and purge/desorbtion phases by pilot valves 65, 66, 67 operated by cams 30, 31, 32 respectively, mounted for rotation on a shaft 33 driven by the compressor through a reduction gear box 35. A flueric partial pressure sensor 80 senses the partial pressure of oxygen in the oxygen-enriched air delivered from the concentrator unit and, by way of low pressure transducers 81, 82, signals a flow control valve 86 to control flow of hydraulic fluid to an inlet 19 of the compressor 10. Variation of the hydraulic flow to the compressor causes corresponding increase of decrease in the rotational speed of the shaft 33 and cams 30, 31, 32 so as to control cycling of the molecular sieve beds to vary the oxygen concentration in the delivered oxygen-enriched air to maintain the partial pressure of oxygen substantially constant irrespective of changes in aircraft altitude. The apparatus dispenses with a requirement for engine compressor stage bleed air as supply air for the concentrator unit and has minimal requirement for use of electrical systems.

Aircraft on-board gas generating apparatus

A molecular sieve bed container provides a plurality of molecular sieve bed chambers. The chambers are formed by tubular wall members concentrically located within a tubular outer housing and are closed at their ends by end closure members. One end closure member incorporates valves (not shown in FIG. 1) for controlling supply of charge gas to the sieve bed chambers and venting of purge gas from the sieve bed chambers. The other end closure member incorporates valves for controlling passage of product gas from the sieve bed chambers to an outlet (not shown) and portways for permitting some of the product gas to flow back through the sieve bed chambers as purge gas during a purge/vent phase. In the illustrated embodiment three sieve bed chambers are filled with a molecular sieve material which is given to removal of nitrogen from air supplied to the container as charge gas while two chambers are filled with a molecular sieve material which is given to removal of oxygen whereby supplies of oxygen-enriched air and nitrogen-enriched air are delivered as product gases.

Molecular sieve bed containers

A fluid pressure intensifier device particularly suited for intensifying the pressure of a gas has a plurality of piston and cylinder compression stages of sequentially reducing volume connected by flow passages (FIG. 5b) for conducting fluid to be pressure intensified sequentially through the compression stages. Individual pressure fluid powered driving mechanisms for each piston or cylinder compression stage comprise driving piston and cylinder assemblies controlled to operate in sequence by a rotatable port plate. The port plate is rotatable by a positive displacement pressure fluid motor actuated by the pressure fluid powering the driving piston and cylinder assemblies, the outer gear of the motor being constituted by the rotatable port plate.

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Somerset, United Kingdom

Robin H Searle