Fuel actuated bleed air system

Abstract

A gas turbine engine bleed air system includes one or more fuel-actuated bleed air supply valves and, in some cases, a pneumatically actuated overpressure valve. Each fuel-actuated bleed air supply valve is mounted on a bleed air supply conduit and is coupled to a source of pressurized aircraft fuel. Each fuel-actuated bleed air supply valve is responsive to the pressurized aircraft fuel to move to a plurality of valve positions and to regulate compressed air pressure in the bleed air supply conduit, downstream of the fuel-actuated bleed air supply valve. The pneumatically actuated overpressure valve is mounted on the bleed air conduit downstream of each of the fuel-actuated bleed air valves and pneumatically regulates or shuts off pressure independent of fuel pressure or electrical signals.

Description

PRIORITY CLAIMS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 376,072 filed Aug. 23, 2010.TECHNICAL FIELD[0002]The present invention generally relates to bleed air systems, and more particularly relates to aircraft bleed air systems.BACKGROUND[0003]Many current aircraft use bleed air extracted from the main engines to supply conditioned air for various pneumatic systems throughout the aircraft. This includes commercial air transport aircraft, business jets, and military aircraft that are powered by turbo-jet, turbo-fan, and turbo-prop engines. The air extracted from the main engines is supplied to and controlled by a bleed air system (BAS). The BAS is typically comprised of a series of valves, ducting, and a pre-cooler, and extracts air from different ports of the compressor section of a turbine engine. This high pressure and high temperature air is then regulated and cooled before it is delivered downstream to the aircraft pneumatic systems.[0004]T...

AI Technical Summary

Benefits of technology

[0028]The bleed air control system 100 described herein uses fuel as the actuation medium to actuate the bleed air system valves. There are many benefits to using fuel instead of bleed air as the actuation medium. For example, when compared to bleed air, fuel is relatively cooler and cleaner, it can act as a lubricant and a damping medium, and it is supplied at a relatively constant and relatively high pressure. The relatively lower fuel temperatures enable electrical devises on the bleed air system valves to operate at design temperatures without the need for cooling air, spacers, or remote mounting, which p

Problems solved by technology

While generally safe, reliable, and robust, there are potential drawbacks associated with using bleed air to actuate the pneumatic actuators.

Some of these drawbacks include temperature, vibration, contamination, and the size and weight of the actuators.

Temperature, vibration, and contamination can reduce overall component reliability.

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