1. Field of the Invention
The present invention generally relates to compressor surge bleed valve (BOV) actuators for gas turbine engines.
2. Description of the Prior Art
Compressor surge bleed valves are a well known method to protect against compressor surge. Accurately controlling bleed allows the engine performance to be controlled to prevent surge. Most prior art BOVs are two-position (open/closed) type, but variable position BOVs are also known, as exemplified by U.S. Pat. No. 3,849,020 issued to Eastman on Nov. 19, 1974 and U.S. Pat. No. 4,391,092 issued to Arnett on Jul. 5, 1983. Such variable position BOV systems generally include actuators which are complex in manufacture and operation requiring numerous parts which are subject to failure and which are responsive to complex signals relying on numerous compressor feedback measurements for achieving discrete positioning of the bleed valves to intermediate positions.
There is thus a need for a new compressor bleed valve actuator which is comparatively less complex structurally, less expensive to manufacture, more reliable, lighter in weight and which provides for intermediate bleed-off flow without the added complexity of compressor feedback measurement.