Normalair-garrett (holdings) Limited

James C Foote

Michael W Harral

Peter J Rowland

Alec J Aldworth

Derrick J Puplett

Humphrey A Hamlin

George F Stevenson

A two-way check valve for a breathing gas supply assembly, comprises a body, a first inlet in the body for receiving a normal breathing gas flow, an outlet for delivering a gas flow from the body, first passage means communicating the first inlet with the outlet, second passage means communicating the second inlet with the outlet, a valve member mounted internally of the body so as to be movable between a first position in which it closes communication between the second inlet and the outlet and a second position in which it closes communication between the first inlet and the outlet, and resilient means biasing the valve member towards the first position.

Aircrew breathing systems

Air-oxygen mixture control apparatus includes a pressure control valve arrangement for substantially equalizing the pressures of oxygen and air supplied to the apparatus at variable pressures. A volume flow control arrangement produces volume flows of oxygen and air appropriate for mixing to provide gas of desired oxygen concentration to a breathing demand regulator for breathing by an aircraft aircrew member. An aneroid acts to occlude the supply of air when the aircrew member is exposed to low aircraft ambient atmospheric pressure so that undiluted oxygen is made available for breathing. The apparatus overcomes the problem of mixing oxygen with air when either one or both is supplied from a variable pressure source, such as is the case when high pressure air from a compressor stage of a gas turbine engine is used for dilution purposes.

Air-oxygen mixture controllers for breathing demand regulators

An aircrew breathing regulator having facility for mixing ambient air with oxygen-enriched breathing gas in supplying breathing gas to an end user, includes a demand valve connected between an inlet for receiving oxygen-enriched breathing gas and an outlet for delivering breathing gas to the end user. Ambient air is entrained by flow of oxygen-enriched breathing gas through an injector nozzle to enter an ambient air inlet and mix with the oxygen-enriched breathing gas downstream of the demand valve. Pressure build-up downstream of the demand valve resulting from the flow restricting effect of the injector nozzle causes a pressure feedback onto a head of the valve tending to force it closed. This is overcome by nullifying the action on the demand valve of downstream pressure so that the valve is pressure balanced.

Breathing demand regulations

Inflation pressure of an aircrew G-suit is set by a servo-pressure which controls movement of inflation gas supply and vent valves 126 and 127, respectively. Servo-pressure is regulated by a torque motor controlled valve 124, 125 which receives a servo-demand signal from an electronic control unit (ECU) 123. The ECU receives an inflation pressure demand signal P.sub.DEM from an aircraft systems computer 120 which stores schedules of G-suit inflation pressure against increasing acceleration and decreasing cabin ambient pressure. The computer is programmed to look-up and output the higher one of values for inflation pressure dependent upon values of acceleration signals G.sub.Z and cabin ambient pressure signals P.sub.AMB input to the computer by sensors 121 and 122, respectively. The ECU compares an existing G-suit inflation pressure P.sub.O signal with the inflation pressure demand signal and generates a compensated error signal which is combined with the inflation pressure demand signal to provide the servo-demand signal. The use of the ECU for the computationally intensive control task optimizes the use of the aircraft system computer. A combined breathing demand regulator and G-suit inflation pressure control valve which continues to function in the absence of electrical power after bail-out from an aircraft is also disclosed.

Aircraft aircrew life support systems

A breathing demand regulator for use in aircrew life support apparatus has an aneroid capsule 56 coacting with a valve head 50 to restrict outflow from a breathing pressure control chamber 32. The aneroid capsule expands to move the valve head in the event of aircraft cabin altitude rising above a predetermined level due to loss of cabin pressure. An end face 53 of a valve stem 51 supporting the valve head senses inflation pressure of an aircrew G-suit by way of a passageway 59 for movement of the valve head in the presence of G-load. This arrangement provides for increased control pressure and, hence, increased breathing gas pressure in a regulator outlet 13, in meeting the higher of requirements for positive pressure breathing to protect an aircrew member exposed to both G-load and high aircraft ambient altitude (say above 12000 meters). The regulator is disclosed in combination with an anti-G valve arrangement 90, 100 and a G-suit inflation control valve arrangement 60, 61 and 120, 121 that provides the higher of G-suit inflation pressure requirement for protecting the aircrew member when exposed to high aircraft ambient altitude in the presence of G-load.

Aircraft aircrew life support apparatus

Aircraft aircrew life support apparatus has a G-protection garment inflation pressure control valve disposed in a common body with a breathing demand regulator. Inflation pressure output by the garment inflation pressure control valve is ducted within the body to be directly applied as an operating force to a valve controlling outflow from a breathing-pressure control chamber of the regulator whereby positive pressure breathing obtains in the presence of G-load. The garment inflation pressure control valve comprises a pressure balanced valve adapted to be displaced against the bias of a spring in an opening direction by a pneumatic actuator. The pneumatic actuator is controlled by signals from an accelerometer sensing G-load for inflation of the garment when the aircrew member is subject to high G-load (typically in excess of 2G) and by signals from a cabin pressure sensor for inflation of the garment if the aircrew member is exposed to high altitude (typically in excess of 12000 metres). The pneumatic actuator is subject to feedback control responding to garment inflation pressure.

Aircraft aircrew G-responsive valve system for controlling breathing gas

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.

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Yeovil, United Kingdom

James C Foote