DEVICE FOR EMERGENCY OPERATION OF ACTUATORS
A device for emergency operation of pneumatic or hydraulic actuators. For normal operation of the actuator, an operation cycle includes at least a proportional valve for switching to different operational conditions of the actuator and related engine components. The proportional valve is arranged in a supply line of pressurized liquid/gas and in a drain line connected to a tank, and control means for operation control and supervising functions. An emergency cycle is attached to the operation cycle of the actuator which is provided with: at least one solenoid valve for initiating an emergency operation impulse in case of detected failures; a plurality of pneumatically/hydraulically operated switch valves which may be activated through said impulse of an emergency signal from said solenoid valve; and whereby the emergency cycle is adapted to bypass said proportional valve in emergency situations and to either block said actuator in its actual position or to bring said actuator in a predefined safe position.
1 . A device for emergency operation of pneumatic or hydraulic actuators, which have for normal operation of the actuator an operation cycle; the device comprising: at least a proportional valve for switching to different operational conditions of said actuator and related engine components, the proportional valve being arranged in a supply line of pressurized liquid/gas and in a drain line connected to a tank, and control means for operation control and supervising functions, wherein an emergency cycle is attached to said operation cycle of said actuator which is provided with at least one solenoid valve for initiating an emergency operation impulse in case of detected failures, a plurality of pneumatically/hydraulically operated switch valves which may be activated through said impulse of an emergency signal from said solenoid valve, and whereby the emergency cycle is adapted to bypass said proportional valve in emergency situations and to either block said actuator in its actual position or to bring said actuator in a predefined safe position.
2 . The device according to claim 1 , further comprising means for the detection of a correct functioning of said actuator are provided for supplying an input signal or emergency signal to said control means.
3 . The device according to claim 1 , wherein said control means are connected to said at least one solenoid valve for automatically switching to an emergency operation in case of failures in the normal operation modus of said actuator.
4 . The device according to claim 1 , further comprising a first solenoid valve wherein upon activation of said first solenoid, said actuator is blocked in its actual position.
5 . The device according to claim 1 , further comprising a first solenoid valve and a second solenoid valve wherein upon simultaneous activation of them said actuator is brought into a predefined safe position, in particular an end position.
6 . The device according to claim 5 , wherein said predefined safe position is an extended position of said actuator corresponding in particular to a closed position of related engine components.
7 . The device according to claim 1 , wherein said emergency cycle comprises a flow control valve for adjusting a switching speed from normal operation to emergency operation.
8 . The device according to claim 1 , wherein said control means are adapted to interrupt the emergency operation and resume normal operation upon request of a user.
9 . The device according to claim 1 , further comprising a detector for supervising the position of said proportional valve is provided.
10 . The device according to claim 1 , wherein said actuator is a hydraulic actuator of variable inlet guide vanes of a gas turbine.