Power plants – Combustion products used as motive fluid
Reexamination Certificate
2000-03-03
2001-12-11
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
C029S889220
Reexamination Certificate
active
06327844
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to turbine engines, and, more particularly, to turbine engines including flow restrictors.
A turbine engine typically includes a compressor assembly and a combustor assembly, each including a plurality of bleed air ports. The bleed air ports extend through a casing surrounding the compressor and combustor, and in operation, a portion of the compressed air flowing through the compressor is extracted through a bleed air supply system (BASS) attached to the bleed air ports. The bleed air may be used, for example, by an environment control system (ECS) to provide compressed air in the cabin of an aircraft or to aid in restarting an engine which has been shut down.
In known engines, flow restrictors are installed in the bleed air ports. Each flow restrictor has an internal shape similar to that of a venturi tube which restricts an amount of airflow being extracted and maintains and/or increases the pressure of the airflow exiting the bleed ports into bleed ducts. The bleed ducts channel the airflow from the bleed ports and retain the flow restrictors within the bleed ports. Over time, vibrations generated while the engine operates may cause the bleed ducts to loosen from the bleed ports resulting in a misalignment of the associated flow restrictor. Additionally, bleed ducts may be removed from bleed ports for maintenance, and the installed flow restrictors may fall from the engine and be easily damaged.
Other engines include flow restrictors which are retained within the bleed ports with intricate retaining systems. Such retaining systems permit the bleed ducts to attach to the bleed ports while permitting bleed air to pass through the flow restrictors. Such retaining systems are expensive and over time may loosen as a result of engine vibrations.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment, a flow restrictor includes a body which permits a flow restrictor to be self-retained within a bleed port. The bleed ports are located over various portions of a gas turbine engine and extend through an engine casing. Each bleed port includes an inner wall which defines a shape similar to that of a venturi tube including a converging portion, a throat, and a diverging portion. The flow restrictor body extends between a first and a second end, and includes a bore also extending between the first and second ends. A slot extends between the first and second ends of the flow restrictor body.
During assembly, when the slot is formed, a spring-like force is induced within the flow restrictor body causing the body to expand radially outward. The flow restrictor is circumferentially compressed and inserted within the bleed port. After the flow restrictor is inserted within the bleed port, the circumferential compression is released and the spring-like force causes the flow restrictor to expand outwardly to contact and conform to the inner walls of the bleed port. Friction between the flow restrictor and the bleed port inner walls causes the flow restrictor to be retained within the bleed port. Accordingly, when a bleed duct is attached to and/or removed from the bleed port, the flow restrictor is retained within the bleed port.
REFERENCES:
patent: 2499315 (1950-02-01), Johnson
patent: 2808996 (1957-10-01), Delfox
patent: 3972641 (1976-08-01), Harner et al.
patent: 4919108 (1990-04-01), Larson
Casaregola Louis J.
General Electric Company
Herkamp Nathan D.
Hess Andrew C.
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