Abstract: A fast opening valve apparatus includes an electronic sensing circuit to determine when a positional error signal exceeds a predetermined reference value corresponding to an opening rate reference value. The sensing circuit provides a fast open command signal which is applied to a solenoid valve which is hydraulically coupled in parallel with a control servo valve. The control servo valve hydraulically couples a primary source of hydraulic fluid under pressure to a valve actuator which is mechanically coupled to a valve stem of an associated steam valve desired to be controlled. The activated solenoid valve opens a supplemental hydraulic fluid path between the valve actuator and the primary source of hydraulic fluid. To ensure an adequate hydraulic fluid pressure at the input of the servo valve and solenoid valve, an auxiliary source of hydraulic fluid under pressure may be coupled upstream of the servo valve and solenoid valve.

Abstract: A two-stage hydraulic solenoid valve for controlling the application or release of hydraulic pressure to components of a steam turbine control system. The valve includes a primary hydraulic circuit in which a floating poppet operates between first and second valving positions to connect the valve's outlet port to either an inlet port or a drain port so that the connected control system components receive full hydraulic pressure or are provided with a pressure release path. A secondary hydraulic circuit controls the poppet position through a solenoid actuatable ball and valve seating arrangement wherein a ball is alternatively positioned between a pair of valve seats to switch fluid connections to poppet actuation chambers, one such chamber being located at each end of the poppet. The ball is positioned in sealing contact with one valve seat by the solenoid and is returned to the other seat by fluid pressure upon deactivating the solenoid.

Abstract: Apparatus for individually isolating the hydraulic actuators of steam valves for a steam turbine while the turbine remains in operation and while all other steam valves associated with the turbine remain functional. Isolation is achieved by providing a manual isolation valve for blocking the flow of hydraulic fluid from a main supply; a flow restrictor to limit the inflow of hydraulic fluid; and a flow direction control means to limit hydraulic fluid to flow only from the actuator toward an emergency trip hydraulic fluid supply.

Abstract: A shut-off valve may control the flow of high-pressure fluid in an on or off manner. The valve includes a valve housing having an axial bore therethrough with a valve member slidable therein. The valve member is formed with a hemispherical poppet which, in one position, is seated between a valve inlet port and a valve outlet port. The valve member is floatably mounted within the axial bore so as to render the hemispherical poppet self-aligning with respect to the valve seat. The valve is remotely actuated by a valve actuating fluid.