Aeronautics and astronautics – Aircraft structure – Passenger or crew accommodation
Reexamination Certificate
1999-02-09
2001-04-17
Swiatek, Robert P. (Department: 3643)
Aeronautics and astronautics
Aircraft structure
Passenger or crew accommodation
C454S076000
Reexamination Certificate
active
06216981
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an environmental control system an in particular to an environmental control system suitable for use in a vehicle such as an aircraft.
BACKGROUND OF THE INVENTION
Conventionally, an aircraft is provided with an environmental control system in which air is taken from the compressor of one or more of its engines and is cooled and dried before being mixed with recirculated cabin air. The air mixture is then supplied to the aircraft cabin. Temperature adjustments are made to the air by mixing it with warm air taken from the engine or engines.
Such environmental control systems are effective in the provision of an acceptable aircraft cabin atmosphere. However, they do have drawbacks in that taking air from the engine's compressor has a detrimental effect upon overall engine operating efficiency and large amounts of ducting are required to direct the air around the aircraft.
A way of avoiding the drawbacks of such environmental control systems is disclosed in U.S. Pat. No. 4,546,939. In U.S. Pat. No. 4,546,939, an aircraft environmental control system is described which takes no air from the aircraft's engines. Instead, electrical power derived from the engine, or alternatively from a ground supply when the aircraft is parked, is used to drive a compressor which compresses ambient air. Air from the compressor is directed through a heat exchanger to cool it before entering a turbine through which it expands to provide further cooling and water vapour condensation. The cooled air is then passed through a further heat exchanger before being directed into the aircraft's cabin.
In the system of U.S. Pat. No. 4,546,939, the compressor and turbine are mechanically interconnected. This, unfortunately, has an adverse effect upon overall operating efficiency.
It is an object of the present invention to provide an environmental control system in which the above-mentioned drawbacks are substantially avoided.
SUMMARY OF THE INVENTION
According to the present invention, an environmental control system comprises an air compressor, an electric motor to drive said air compressor, an electrical power control and distribution system to receive electrical power and to direct at least some of that electrical power to drive said electric motor, a turbine to receive and expand air delivered thereto by said compressor to thereby cool said air, an electrical generator driven by said turbine, said electrical generator providing at least some of the electrical power received by said electrical power control system, and a water separator to remove water from air exhausted from said compressor.
A first heat exchanger is preferably provided downstream of said compressor to reduce the temperature of air exhausted from said compressor.
Said first heat exchanger may be positioned to place air exhausted from said compressor in heat exchange relationship with a flow of ambient air.
Water, which is in operation removed by said water separator from air exhausted from said turbine, may be directed into said flow of ambient air upstream of said first heat exchanger.
A second heat exchanger may be provided downstream of said first heat exchanger, said second heat exchanger being adapted to put air exhausted from said first heat exchanger in heat exchange relationship with air exhausted from said water separator.
A condenser is preferably provided to place air exhausted from said second heat exchanger in heat exchange relationship with air exhausted from said turbine.
Preferably heating means are provided downstream of said turbine to increase the temperature of air exhausted from said turbine to a temperature sufficiently high to prevent the formation of ice in said air.
Said heating means may be an electrical heater powered by said electrical power control and distribution system.
Alternatively, said heating means may comprise a discrete flow of air exhausted from and heated by its passage through said compressor.
Said air exhausted from said turbine is preferably heated electrically to the temperature required of air constituting the output from said system.
Said system may be adapted to control the environment of the interior of an aircraft.
Said electrical power is at least partially derived from generators powered by the propulsion engines of said aircraft.
Since the compressor and turbine of the environmental control system are not mechanically interconnected, they are able to operate at their optimum speeds.
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patent: 2937011 (1960-05-01), Brahm
patent: 4419926 (1983-12-01), Cronin et al.
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patent: 4706908 (1987-11-01), Huffman et al.
patent: 5299763 (1994-04-01), Bescoby et al.
patent: 5967461 (1999-10-01), Farrington
patent: 6127758 (2000-10-01), Murry et al.
patent: 1316275 (1973-05-01), None
Manelli, Denison & Selte PLLC
Rolls-Royce plc
Swiatek Robert P.
Taltavull W. Warren
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