Abstract: A hydraulic servo system for steam turbines providing rapid closing of the main valve between the turbine and the boiler to stop the operation by opening a drainage valve whereby hydraulic fluid is drained immediately from the servo motor which normally maintains the main valve in open position. Secondary valve means are actuated by the resultant pressure drop to drain hydraulic fluid from a portion of the servo system, which is throttled from the servo motor portion, after a predetermined time lapse, and to block off supply of hydraulic fluid to the system. The main valve may be reopened by closing the drainage valve and by actuating the secondary valve means to reconnect the hydraulic fluid source to the throttled portion of the system whereby pressure therein is rapidly restored to a degree sufficient to supply fluid to the servo motor.

Abstract: A control circuit arrangement for a gas turbine engine has first and second identical control circuits which are responsive to groups of input signals to provide nominally identical first and second output signals. It is arranged that input signals to the first control circuit are nominally identical with corresponding input signals to the second control circuit. Means are provided, responsive to malfunction of either one of the first and second control circuits, to render the malfunctioning circuit inoperative and to render the other of the control circuits operative. A third control circuit is responsive to at least one pair of corresponding input signals to the first and second circuits, to provide a third output signal to the engine. The first, second and third output signals do not control the engine reheat system, and the arrangement may include a fourth control circuit for controlling this reheat system.

Abstract: A gas turbine engine has variable vanes in the rear compressor that are automatically scheduled to their optimum position for proper engine operation by a closed loop primary engine control system in response to selected engine operating conditions. A failure in the engine control system may cause the variable vanes to be locked in a position which degrades the engine aerodynamics to a dangerous level. An emergency controller is connected to schedule the position of the variable compressor vanes in an open loop manner in response to changes in the power lever when a failure of the primary engine control system occurs.

Abstract: A digital computer control system is provided for operating a steam turbine in an electric power plant. The computer develops steam valve position signals to control turbine speed and load. Various turbine temperature, pressure and other process parameter signals are coupled to the computer which stores the parameter values along with other parameters such as control loop setpoints in its memory. Another computer at the plant level or at the system dispatch level is coupled to the turbine computer through a data link which includes data link programs in each computer and data transmitter and receiver circuitry connected to the two computers. The higher level computer is the controlling computer on the data link. Control words are used to identify data transmission modes and validity checks are made on transmitted words. Turbine computer core data is accessible and transmittable to either higher level computer.

Abstract: The throttle and governor valves of a steam turbine are operated by a digital computer control system to provide speed and load control for the turbine. The computer includes a speed and load control which periodically generates control outputs and a separate logic control which responds to panel and contact inputs to generate logicals which structure the speed and load control. An analog scan periodically enters feedback parameters into the computer for use by the controls. An input contacts scan enters feedback logicals into the computer on demand, or under certain conditions periodically. A monitor operates with an auxiliary synchronizer to control the execution of the scans and the controls. The speed and load controls are bid for execution once each second to generate the control outputs which are applied to an external electrohydraulic control for the valves.

Abstract: A combined digital computer/analog control system for operating a boiling water reactor steam turbine power plant, wherein the digital computer provides a throttle pressure setpoint, speed error and load demand for controlling the plant depending upon the operational states of the system, is disclosed. The analog portion of the system also controls the plant in cooperation with the digital computer for certain operational states and conditions when the digital computer is in operation; and the analog system alone controls the plant when the digital computer is out of service. The transfer between such control is effected depending upon the operational states of the system and certain of the components therein. The system also includes in the digital computer portion, the provision for preventing a load demand which is outside the limits of the reactor circulation system when the reactor is in a state of automatic operation.

Abstract: A combined digital computer/analog control system for operating a boiling water reactor-steam turbine-power plant wherein one of two analog throttle pressure controllers is used for controlling the inlet and bypass valves. One of the pressure controllers is biased to provide a higher signal than the other; and such nonbiased controller is the one selected to control the valves. Each controller includes a pressure transducer, a summing device and amplifier, and a lead/lag circuit together with the appropriate power supply.A failure detection system is used to switch the controllers from automatic to manual when a predetermined combination of controller components becomes defective. Also, such system is so organized that a transducer failure for one controller causes the other controller to assume control regardless of whether such failure results in a higher or lower than proper signal.