Controller for controlling a bleed valve including a first body with an internal cavity connected to an air inlet port and an air outlet port, a second body including a chamber, a mobile member in the cavity and in the chamber, connecting the two bodies. The member is mobile between a position whereby the ports fluidly communicate and a position whereby the ports are isolated, the member further including two pistons housed in the chamber and defining in this chamber at least two spaces. The controller also includes a fluid supply for at least one of the spaces for the purpose of moving the pistons in the chamber.

A bleed valve for use in a gas turbine engine of an aircraft includes a high-pressure cavity coupled to a valve terminal, which is itself coupled to a cap, which cap includes a valve seat configured to be sealed by a tube that serves as the valve gate. The tube is operably coupled to a movable end of a bellows, which is positioned within the high-pressure cavity. The opening and closing of the valve is controlled by the movement of the bellows within the high-pressure cavity, and, in turn, the movement of the tube towards the valve seat, with the valve closing as the bellows compresses.

A system for use in servicing a machine. The system includes a tubular body including a longitudinal axis, a tip end, a dispensing nozzle defined at the tip end, and an interior channel in flow communication with the dispensing nozzle. The tubular body is configured to be flexible. An actuator is configured to selectively modify an orientation of the tubular body, and a reservoir is in flow communication with the interior channel. The reservoir is configured to supply a maintenance fluid to the tubular body for discharge from the dispensing nozzle.

A bleed valve includes a housing with an inlet coupled to an outlet by a duct, a guide tube with an orifice fixed in the housing between the inlet and the outlet, a piston, and baffle. The piston is slideably supported on the guide tube and is movable between an open and a closed position, the duct fluidly coupling the inlet and outlet in the open position, the duct fluidly separating the inlet and outlet in the closed position. The orifice fluidly couples the inlet and outlet in the open and closed positions to move piston between the open and closed positions according to differential pressure between the bleed valve inlet and outlet. The baffle is slideably supported by the guide tube to set the differential pressure at which the piston moves between the open and closed positions. Gas turbines and differential pressure adjustment methods are also described.

A method of reducing rotor bow in a high pressure rotor of a gas turbine engine that has in axial flow a low pressure rotor and a high pressure rotor. The method involves storing bleed air from the gas turbine engine when the engine is running to provide stored pneumatic energy; and using that stored pneumatic energy after the engine has been shut-down to rotate the high pressure rotor at a speed and for a duration that reduces rotor bow. A gas turbine engine wherein rotor bow in the high pressure rotor after engine shut-down has been reduced by carrying out the aforesaid method is also disclosed.

A bleed valve for use in a gas turbine engine of an aircraft includes a high-pressure cavity coupled to a valve housing, which includes a valve seat configured to be sealed by a system poppet. The system poppet is operably coupled to a shaft that is itself coupled to a movable end of a bellows, which is positioned within the high-pressure cavity. The opening and closing of the valve is controlled by at least one cavity air port that is configured to inject a first fluid into the high-pressure cavity, thus compressing the bellows, and by a servo air port that is configured to inject a second fluid directly into the bellows, to expand it.

A compressor shroud assembly is disclosed comprising a dynamically moveable impeller shroud, a static compressor casing, an air piston mounted between said impeller shroud and said compressor casing, and a clearance control system. The air piston effects axial movement of said impeller shroud responsive to a supply of actuating air. The clearance control system regulates the pressure of actuating air in said air piston and comprises a supply conduit having a supply modulating valve and a discharge conduit having a blowoff check valve. The blowoff check valve is set to open at a predetermined differential pressure between pressure of the air piston and pressure of the supply of actuating air.

A bleed valve includes a housing with an inlet coupled to an outlet by a duct. A guide tube is fixed within the housing between the inlet and the outlet. A piston with a piston orifice is slideably supported on the guide tube and movable between an open position and a closed position. The duct fluidly couples the inlet to the outlet in the open position, the duct fluidly separates the inlet from the outlet in the closed position, and the piston orifice fluidly couples the inlet with the outlet in the open position and the closed position to move piston between the open position and the closed position according to differential in pressure between the inlet and the outlet of the bleed valve. Compressors, gas turbine engines, and methods of controlling fluid flow are also described.

The invention provides a pneumatic circuit for supplying air to at least one discharge valve that is pneumatically actuated and to at least one depressurizing device for depressurizing an oil enclosure in a turbine engine, the pneumatic circuit comprising: a pneumatic control unit having at least one solenoid valve supplying compressed air to a discharge valve of a compressor of the turbine engine; at least one depressurizing device for depressurizing an oil enclosure of the turbine engine, the device including a compressed air ejector for depressurizing the oil enclosure; and a pneumatic bistable member that is supplied with air by different first and second compressed air sources and that is suitable for supplying the pneumatic control unit and the depressurizing device with air coming from the first or the second compressed air source as a function of the operating speed of the turbine engine.

A compressor shroud assembly is disclosed comprising a dynamically moveable impeller shroud, a static compressor casing, an air piston mounted between said impeller shroud and said compressor casing, and a clearance control system. The air piston effects axial movement of said impeller shroud responsive to a supply of actuating air. The clearance control system regulates the pressure of actuating air in said air piston and comprises a supply conduit having a supply modulating valve and a discharge conduit having a blowoff check valve. The blowoff check valve is set to open at a predetermined differential pressure between pressure of the air piston and pressure of the supply of actuating air.