Provided is an electrohydrostatic actuation system including an emergency shut-off circuit to be actuated stably with a simple configuration. The electrohydrostatic actuation system includes: a hydraulic cylinder (24) including a piston (25) to which a valve element is connected, a first chamber (24A), and a second chamber (24B); a hydraulic pump (21) configured to supply hydraulic fluid to the first chamber (24A) or the second chamber (24B); a servo motor (M) configured to drive the hydraulic pump (21); a shuttle valve (11) configured to establish communication to a downstream side under a state in which a hydraulic pressure generated by the hydraulic pump (21) is maintained; a solenoid valve (12) configured to receive the hydraulic pressure via the shuttle valve (11) as a pilot pressure; and a logic valve (13) including a first port configured to receive the pilot pressure from the solenoid valve (12), and a second port to be communicated to the first chamber (24A) of the hydraulic cylinder (24). When the solenoid valve (12) is brought to a de-energized state, the pilot pressure of the logic valve (13) is released, and the logic valve (13) causes the hydraulic fluid in the first chamber (24A) communicated to the second port to flow into the second chamber (24B) so that emergency shut-off of the valve element is achieved by a return spring (26).

A valve assembly includes a valve moveable between an open position where hydraulic fluid flow is permitted and a closed position where hydraulic fluid flow is blocked. A controller includes a magnetometer adapted to measure a magnetic flux through at least a portion of a solenoid linear actuator that moves the valve. A magnetic flux value measured by the magnetometer corresponds to a linear position of the regulating member relative to the port.

To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

Provided is a fluid actuator capable of safely driving a drive target. An air actuator using air as a working fluid includes an X-axis pressure sensor that measures air pressures PX+ and PX− along one drive axis, which drives a drive target in an X direction, a Y-axis pressure sensor that measures air pressures PY1+, PY1−, PY2+, and PY2− along two drive axes, which drive the drive target in a Y direction, and an acceleration detection unit that detects translational acceleration and rotational acceleration generated in the drive target on the basis of the measured air pressures PX+, PX−, PY1+, PY1−, PY2+, and PY2−.

An actuator assembly which has a primary force module having a compression spring can be is compressed by a first fluid pressure-operated piston reciprocally mounted in the primary force module. There is a tandem piston module connected to the primary force module which has a second fluid-activated piston. When the spring of the primary force module is compressed, indicating that an attached valve is in the open position, the tandem module is actuated to apply a counter balancing force against the primary piston which allows the spring to expand and move the primary piston to a position which is sufficient to permit movement of the valve element of the actuated valve to indicate the valve is not stuck in an open position.

To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

A valve actuator system includes a valve actuator assembly having a body defining an interior cavity and a piston coupled to a piston rod and movable within a piston cylinder provided within the interior cavity. The piston cylinder has a first chamber on a first side of the piston and a second chamber on a second rod side of the piston. One or more electronic components are disposed within the interior cavity and include at least one processor. The one or more electronic components are configured to move the piston via controlled air pressure and to continuously monitor and/or determine a position of the piston rod relative to the piston cylinder. A fail-safe reservoir is coupled to a source of air and is connected to both the first chamber and the second chamber to provide operating air thereto. A controller is configured to communicate with the processor of the one or more electronic components remote from the body and to selectively monitor and control functions of the valve actuator systems from the controller. The first chamber is maintained at a substantially constant pressure and the second chamber is varied in pressure to move and/or to hold the position of the piston to place the piston rod at a desired position relative to the piston cylinder.

Systems and methods for protecting a turbomachine may include a trip throttle valve having a throttle valve assembly and a trip valve assembly. The trip valve assembly may include a plurality of trip valves fluidly coupled to a hydraulic cylinder of the throttle valve assembly via a first flow path and a second flow path in parallel with one another. The trip valve assembly may also include a plurality of isolation valves fluidly coupled to the hydraulic cylinder via the first flow path and the second flow path. The plurality of isolation valves may be configured to selectively prevent fluid communication between the plurality of trip valves and the hydraulic cylinder to allow testing of one or more of the plurality of trip valves during operation of the turbomachine.

An example valve includes: (i) a valve body comprising a supply port and an operating port; (ii) a sleeve comprising a first opening fluidly coupled to the supply port, a second opening fluidly coupled to the operating port, and a seat; (in) a spool configured to move axially within the sleeve, wherein the spool is configured to he seated on the seat of the sleeve when the valve is unactuated, and wherein when the valve is actuated, the spool moves such that a gap is formed at the seat; and (iv) a flow restriction disposed downstream of the gap, wherein when the valve is actuated, fluid is allowed to flow from the supply port through the first opening and the gap and through die flow′ restriction prior to flowing through the second opening to the operating port, such that the flow restriction generates an increased pressure level at the gap.

Provided are: a shut-off valve control device which is capable of reducing the difference between a set opening amount and the actual opening amount, when executing a partial valve stroke test; a shut-off valve control system; a method for calculating a shut-off valve control coefficient; and a method for controlling a shut-off valve. This shut-off valve control device is provided with a microcomputer for controlling the opening and closing of a solenoid valve which supplies air from an air supply source, to a cylinder of an air cylinder for controlling a valve shaft of a shut-off valve, and discharges said air. The microcomputer acquires a set opening amount of the shut-off valve. Furthermore, the microcomputer controls the solenoid valve to a value obtained by dividing the acquired set opening amount by a predetermined coefficient C.