Turbine nozzle control

Claim 2

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a power cylinder having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback lever connecting the movable member to the servo valve; cam means activated by the control means providing a movable first fulcrum for the feedback lever to establish a curve of vane angle as a function of power level demand; stop means providing a second fulcrum for the feedback lever; a source of servo fluid under pressure; means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two members moved relatively by the feedback lever, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the source of servo fluid and a return line, and the slave valve being exposed to the pressure between the said restricted paths.

Claim 3

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a power cylinder having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback lever connecting the movable member to the servo valve; cam means activated by the control means providing a movable first fulcrum for the feedback lever to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback lever, the second fulcrum being biased to a position effective to establish a vane angle for acceleration of the engine and the fulcrum being yieldable to provide for overtravel to provide a reversed vane angle; a source of servo fluid under pressure; means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two members moved relatively by the feedback lever, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the source of servo fluid and a return line, and the slave valve being controlled by the pressure between the said restricted paths; and controllable means for alternatively opening, throttling, and closing the return line, such that the cylinder is controlled by the cam means when the return line is open, moves to a position determined by the second fulcrum when the return line is throttled, and moves further to a braking position when the return line is closed.

Claim 4

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a power cylinder having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback lever connecting the movable member to the servo valve; cam means activated by the control means providing a movable first fulcrum for the feedback lever to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback lever, the second fulcrum being biased to a position effective to establish a vane angle for acceleration of the engine and the fulcrum being yieldable to provide for overtravel to provide a reversed vane angle; a source of servo fluid under pressure; means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two members moved relatively by the feedback lever, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the source of servo fluid and a return line, and the slave valve being controlled by the pressure between the said restricted paths; and controllable means for alternatively opening, throttling, and closing the return line, such that the cylinder is controlled by the cam means when the return line is open, moves to a position determined by the second fulcrum when the return line is throttled, and moves further to a braking position when the return line is closed.

Claim 5

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; valve means controlling flow of servo fluid to the motor; a feedback linkage connecting the movable member to the valve means; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand; stop means providing a second fulcrum for the feedback linkage; a source of servo fluid under pressure; and means defining a restricted connection from the source to the valve means; the valve means including two parts moved relatively by the feedback linkage, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line; the valve means including means for reversibly directing fluid to the motor controlled by the pressure between the said restricted paths.

Claim 6

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; valve means controlling flow of servo fluid to the motor; a feedback linkage connecting the movable member to the valve means; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand; stop means providing a second fulcrum for the feedback linkage; a source of servo fluid under pressure; and means defining a restricted connection from the source to the valve means; the valve means including two parts moved relatively by the feedback linkage, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line; the valve means including means for reversibly directing fluid to the motor controlled by the pressure between the said restricted paths.

Claim 7

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting mmeans; valve means controlling flow of servo fluid to the motor; a feedback linkage connecting the movable member to the valve means; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being effective to establish a vane angle for acceleration of the engine; a source of servo fluid under pressure; means defining a restricted connection from the source to the valve means; the valve means including two parts moved relatively by the feedback linkage, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line; the valve means including means for reversibly directing fluid to the motor controlled by the pressure between the said restricted paths; and controllable means for alternatively opening and throttling the return line, such that the cylinder is controlled by the input means when the return line is open and moves to a position determined by the second fulcrum when the return line is throttled.

Claim 8

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting mmeans; valve means controlling flow of servo fluid to the motor; a feedback linkage connecting the movable member to the valve means; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being effective to establish a vane angle for acceleration of the engine; a source of servo fluid under pressure; means defining a restricted connection from the source to the valve means; the valve means including two parts moved relatively by the feedback linkage, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line; the valve means including means for reversibly directing fluid to the motor controlled by the pressure between the said restricted paths; and controllable means for alternatively opening and throttling the return line, such that the cylinder is controlled by the input means when the return line is open and moves to a position determined by the second fulcrum when the return line is throttled.

Claim 9

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; valve means controlling flow of servo fluid to the motor; a feedback linkage connecting the movable member to the valve means; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being biased to a position effective to establish a vane angle for acceleration of the engine and the Fulcrum being yieldable to provide for overtravel to provide reversed vane angle; a source of servo fluid under pressure; means defining a restricted connection from the source to the valve means; the valve means including two parts moved relatively by the feedback linkage, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted path being connected in series between the said restricted connection and a return line; the valve means including means for reversibly directing fluid to the motor controlled by the pressure between the said restricted paths; and controllable means for alternatively opening, throttling, and closing the return line, such that the cylinder is controlled by the input means when the return line is open, moves to a position determined by the second fulcrum when the return line is throttled, and moves further to a braking position when the return line is closed.

Claim 10

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; valve means controlling flow of servo fluid to the motor; a feedback linkage connecting the movable member to the valve means; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being biased to a position effective to establish a vane angle for acceleration of the engine and the Fulcrum being yieldable to provide for overtravel to provide reversed vane angle; a source of servo fluid under pressure; means defining a restricted connection from the source to the valve means; the valve means including two parts moved relatively by the feedback linkage, the members defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted path being connected in series between the said restricted connection and a return line; the valve means including means for reversibly directing fluid to the motor controlled by the pressure between the said restricted paths; and controllable means for alternatively opening, throttling, and closing the return line, such that the cylinder is controlled by the input means when the return line is open, moves to a position determined by the second fulcrum when the return line is throttled, and moves further to a braking position when the return line is closed.

Claim 11

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback linkage connecting the movable member to the servo valve; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand; stop means providing a second fulcrum for the feedback linkage; a source of servo fluid under pressure; and means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two parts moved relatively by the feedback linkage, the parts defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line, and the slave valve being controlled by the pressure between the said restricted paths.

Claim 12

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback linkage connecting the movable member to the servo valve; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand; stop means providing a second fulcrum for the feedback linkage; a source of servo fluid under pressure; and means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two parts moved relatively by the feedback linkage, the parts defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line, and the slave valve being controlled by the pressure between the said restricted paths.

Claim 13

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback linkage connecting the movable member to the servo valve; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being effective to establish a vane angle for acceleration of the engine; a source of servo fluid under pressure; means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two parts moved relatively by the feedback linkage, the parts defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line, and the slave vaLve being controlled by the pressure between the said restricted paths; and controllable means for alternatively opening and throttling the return line, such that the cylinder is controlled by the input means when the return line is open and moves to a position determined by the second fulcrum when the return line is throttled.

Claim 14

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback linkage connecting the movable member to the servo valve; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being effective to establish a vane angle for acceleration of the engine; a source of servo fluid under pressure; means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two parts moved relatively by the feedback linkage, the parts defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line, and the slave vaLve being controlled by the pressure between the said restricted paths; and controllable means for alternatively opening and throttling the return line, such that the cylinder is controlled by the input means when the return line is open and moves to a position determined by the second fulcrum when the return line is throttled.

Claim 15

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback linkage connecting the movable member to the servo valve; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being biased to a position effective to establish a vane angle for acceleration of the engine and the fulcrum being yieldable to provide for overtravel to provide reversed vane angle; a source of servo fluid under pressure; means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two parts moved relatively by the feedback linkage, the parts defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line, and the slave valve being controlled by the pressure between the said restricted paths; and controllable means for alternatively opening, throttling, and closing the return line, such that the cylinder is controlled by the input means when the return line is open, moves to a position determined by the second fulcrum when the return line is throttled, and moves further to a braking position when the return line is closed.

Claim 16

A power turbine nozzle vane angle setting system for a gas turbine engine comprising, in combination, control means operable to set an engine power level demand; a fluid motor having a movable member connectable to vane angle setting means; a fluid pressure operated slave valve controlling flow of servo fluid to the power cylinder; a servo valve for controlling the slave valve; a feedback linkage connecting the movable member to the servo valve; input means actuated by the control means providing a movable first fulcrum for the feedback linkage to establish a curve of vane angle as a function of power level demand for normal steady-state operation of the engine; stop means providing a second fulcrum for the feedback linkage, the second fulcrum being biased to a position effective to establish a vane angle for acceleration of the engine and the fulcrum being yieldable to provide for overtravel to provide reversed vane angle; a source of servo fluid under pressure; means defining a restricted connection from the source to the servo valve; the servo valve including means to vary the operating pressure of the slave valve comprising two parts moved relatively by the feedback linkage, the parts defining two fluid paths each restricted by such relative movement, one path being restricted by relative movement of the first fulcrum and the movable member and the other path being restricted by movement of the movable member relative to the second fulcrum, the said restricted paths being connected in series between the said restricted connection and a return line, and the slave valve being controlled by the pressure between the said restricted paths; and controllable means for alternatively opening, throttling, and closing the return line, such that the cylinder is controlled by the input means when the return line is open, moves to a position determined by the second fulcrum when the return line is throttled, and moves further to a braking position when the return line is closed.