Multi-position BOV actuator

A system for controlling compressor surge in a gas turbine engine comprising:

• at least one bleed valve;
• and at least one pressurized fluid actuator coupled to the bleed valve to operate the bleed valve to control compressor surge, said actuator mounted for movement in a casing between first, second and third positions, to second position being intermediate the first and third positions, wherein the actuator is moved between said positions upon the supply of a pressurized fluid to an operative portion of the actuator, the actuator having at least one selectively openable opening at a location corresponding to the second position for selectively permitting pressurized fluid to exit the operative portion of the actuator and thereby permit the actuator to remain in said second position.

In a gas turbine engine comprising an engine part movable between discrete positions, an actuator coupled to said engine part to actuate the engine part, said actuator comprising a piston mounted for reciprocal movement within a piston casing, said piston being movable from a first end position to a second end position when a pressurized fluid is supplied to a chamber through a first opening defined in said casing, said chamber being defined at least partially by said piston and said piston casing, the actuator including a second opening adapted to remove pressurized fluid from said chamber, wherein said piston is selectively retainable in an intermediate position by bleeding pressurized fluid from said chamber trough the second opening.

A compressor bleed valve system comprising a bleed valve operated by an actuator having a piston slidable in a piston casing between first, second and third positions, said second position being intermediate said first and third positions, a first port provided in said piston casing for allowing a pressurized fluid to be selectively supplied into said piston casing in order to displace said piston from said first position to said third position, and a selectively openable outlet port provided in said piston casing at a location corresponding to said second position, whereby when said piston uncovers said outlet port and said outlet port is opened, the pressurized fluid flowing into said piston casing via said first port is permitted to flow out of said piston casing through said outlet port, thereby causing said piston to remain in said second position thereof.