Aircraft aircrew G-responsive valve system for controlling breathing gas and suit-inflation

• US 5,199,426 A
• Filed: 09/18/1990
• Issued: 04/06/1993
• Est. Priority Date: 09/21/1989
• Status: Expired due to Term

• Current Assignee: Honeywell Normalair-Garrett Ltd. (Honeywell International Inc.)
• Original Assignee: Normalair-Garrett Holdings Limited
• Inventors: Foote, James C., Aldworth, Alec J.
• Primary Examiner(s): Burr, Edgar S.
• Assistant Examiner(s): ASHER, KIMBERLY L
• Application Number:
  US07/584,037
• Time in Patent Office: 931 Days
• Field of Search: 128/205.24, 128/204.29, 128/204.18, 128/205.26, 128/200.24, 128/201.28, 128/201.29, 128/202.11, 128/202.12, 128/204.26, 137/78.5, 137/81.1, 137/48, 137/223, 137/225, 251/61, 251/335.3
• US Class Current: 128/205.24
• CPC Class Codes: A62B 9/022 Breathing demand regulators SCUBA diving regulators B63C11/22
• CPC Class Codes: B64D 10/00 Flight suits helmets in general A42B3/00; breathing helmets A62B18/00
• CPC Class Codes: Y10T 137/2012 Pressure

Abstract

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.

Claims

1. An aircraft aircrew life support system comprising a breathing demand regulator means adapted to be connected with a breathing gas source for regulating delivery of breathing gas to a breathing mask in response to breathing demands of the aircrew member, and, if required, to a counter-pressure garment, the demand regulator including a breathing-pressure control chamber fed with gas to develop a control pressure therein determining the breathing gas pressure delivered by the regulator, aneroid means controlling outflow from the control chamber for increasing breathing gas delivery pressure appropriate to positive pressure breathing above a predetermined altitude, and valve means also controlling outflow from the control chamber for increasing breathing gas delivery pressure appropriate to positive pressure breathing in the presence of high or rapidly changing G-load;

G-protection garment inflation pressure control means disposed in a common body with said demand regulator means for outputting inflation gas to a G-protection garment and to said valve means controlling outflow from the control chamber of said demand regulator means, said G-protection garment control means comprising a spring-biased pressure-balanced valve adapted to be displaced, against the spring bias, in an opening direction by a pneumatic actuator, the pneumatic actuator being subject to feedback control responding to G-protection garment inflation pressure, wherein the feedback control is by electrical signals derived by a pressure transducer sensing inflation pressure and wherein the pressure transducer senses pressure in a chamber subject to inflation pressure but isolated from the flow of inflation gas whereby turbulence effects tending to degrade pressure signals output by the transducer are avoided and duct means in said common body for ducting inflation gas output by said control means to be applied as in operating force to said valve means whereby breathing gas appropriate to positive pressure is delivered by said demand regulator to the breathing mask in the presence of increasing G-load.

2. A system according to claim 1, further comprising means for smoothing the flow of inflation gas in its flow path adjacent to a connection to said chamber, whereby perturbations in the pressure sensed by the transducer are minimised.

3. A system according to claim 2, wherein said inflation gas flow smoothing means comprise a cap supported by a cup spider in the housing and a tapered sleeve on the end of the balanced valve, the cap and the tapered sleeve having a telescoping relationship to each other and enclosing with the balanced valve the valve biasing spring.

4. A system according to claim 3, further comprising port means in said cap and further port means in said balanced valve whereby inflation pressure is effective in said chamber.

5. A system according to claim 1, wherein the pneumatic actuator comprises a plunger carried by a diaphragm defining one wall of an actuating pressure chamber, and wherein said means responsive to variation in G-load for actuating said pneumatic actuator includes an electrically operated torque motor having a valve member for regulating a servo-flow in obtainment of a servo-pressure in said actuating pressure chamber.

6. A system according to claim 5, wherein the torque motor is connected for receiving control signals from an electronic control unit adapted for processing signals from accelerometer means sensing G-load and pressure transducer means sensing aircraft cabin pressure.

7. A system according to claim 1, wherein said means responsive to variation in G-load for actuating the pneumatic actuator is controlled by signals derived from means sensing G-loads and by signals from said transducer sensing aircraft cabin pressure.

8. A system according to claim 1, wherein a vent valve for releasing inflation gas when deflation of the G-protection garment is required is provided within the common body and connected to the inflation gas flow path downstream of the pressure-balanced valve of the G-protection garment control means so that the pressure-balanced valve is effectively isolated from the flow of inflation gas released by the vent valve, whereby contaminants carried in such gas flow cannot enter the pressure-balanced valve mechanism to interfere therewith.