An aircraft thermal hydraulic active-warming system includes an active thermal-warming valve interoperably coupled between a hydraulic pressure line and a hydraulic low-pressure return line and a hydraulic actuator arranged in parallel with the active thermal-warming valve between the hydraulic pressure line and the hydraulic low-pressure return line.

Method of adjusting the pressure balance or a control device, in particular of a servo valve, the requisite adjusting movement being applied by a disc translator.

The subject matter of this specification can be embodied in, among other things, a fluid valve assembly that includes a first fluid port, a second fluid port, a third fluid port, a valve spool configured to be positioned at a first position, a second position away from the first position, a third position away from the first position opposite the second valve position, the valve spool defining a first fluid duct configured to fluidly connect the first fluid port to the second fluid port in the first valve position, a second fluid duct configured to fluidly connect the first fluid port to the third fluid port in the second valve position, and a third fluid duct configured to fluidly connect the first fluid port to the second fluid port in the third valve position.

A servo valve assembly includes a first nozzle opposing a second nozzle and a shaft positioned in the gap between the first and second nozzles. The first and second nozzles are spaced apart by a gap and each nozzle has an outlet opening. The shaft defines a diameter (D) and a circumferential surface and is rotatable about an axis of rotation (R-R). The shaft defines first and second reduced radial portions around its circumferential surface, and the first and second reduced radial portions are in fluid communication with the first and second nozzle outlet openings, respectively. The shaft is configured to rotate between a first position where the first nozzle outlet opening is more occluded by the shaft circumferential surface than the second nozzle outlet opening, and a second position where the first nozzle outlet opening is less occluded by the shaft circumferential surface than the second nozzle outlet opening.

A servovalve having a pilot stage includes two hydraulic elements that are movable relative to each other so as to move a power-directing member, the pilot stage including a linear actuator having a main pusher arranged to modify the relative position of the hydraulic elements. The pilot stage has a position feedback lever.

A piezoelectric ring bender servo valve assembly reduces mechanical wear by removing mechanical components used in prior art servo valves. The assembly does not use torque motor, flapper, and feedback spring. In this manner, no moving parts are required, which reduces maintenance and costs. A pair of piezoelectric ring benders mount adjacently to a pair of nozzles. The piezoelectric ring benders independently regulate the flow of fluid through the nozzles by moving between an open position to enable flowage, and a closed position to restrict flowage. A linear position sensing device measures and provides feedback about the spool position to a valve controller. The valve controller allows the spool valve to move until valve position achieves command position and the force on the spool valve is in equilibrium with pressure difference across spool valve. An H-bridge operable to switch the polarity of a differential pressure applied across to a load.

A servovalve system comprising a pilot stage valve in communication with an hydraulic stage valve, the hydraulic stage valve comprising a valve member movably mounted in a valve chamber to selectively meter fluid flow in a flow path from an upstream inlet port to a downstream outlet port and at least two variable-sized orifices disposed in the flow path between the inlet and outlet ports, an upstream pressure sensor, a downstream pressure sensor, a fluid temperature sensor, a position sensor sensing a linear position of the valve member, a controller that receives input from the upstream pressure sensor, the downstream pressure sensor, the fluid temperature sensor and the position sensor; and the controller configured to provide a control signal to the pilot stage valve as a function of the input from the upstream pressure sensor, the downstream pressure sensor, the fluid temperature sensor and the position sensor.

A servo valve comprising: a fluid transfer valve assembly includes a valve body having a supply port and a control port (C). The valve body cincludes first and second nozzles and a drive member therebetween, arranged to regulate flow of fluid from the supply port to the control port in response to a control signal. The drive member comprises an elongate member arranged to rotate in response to the control signal, and a cylindrical disk mounted on, and arranged to rotate with, the elongate member, between the first and second nozzles, the cylindrical disk having a cam profile such as to vary the spacing (A, B) between the disk and at least one of the nozzles as the cylindrical disk rotates relative to the first and second nozzles.

A servo valve includes a fluid transfer valve assembly comprising a valve body having a supply port and a control port (C1). The valve body has first and second nozzles and a drive member therebetween, arranged to regulate flow of fluid from the supply port to the control port in response to a control signal. The assembly also includes a drive assembly comprising a magnetic coil and a core passing through the coil and configured to move axially with respect to the coil when the coil is powered by a current dependent on the control signal, the drive assembly arranged to move the drive member relative to the first and second nozzles in response to the control signal.

A nozzle with changeable press fit and a method for calibrating a nozzle is described. The nozzle may be used in a nozzle/flapper type servovalve. The method comprises the steps of providing a nozzle within a cylindrical body defining a cylindrical bore, the nozzle having a tubular shape with an outer cylindrical surface and an inner radial surface, the method further comprises the steps of positioning a first, tubular locking member within the nozzle, and axially moving the first, tubular locking member within the nozzle. The first tubular locking member is configured to cause the nozzle to become positionally fixed at a selected position within the bore in response to the first, tubular locking member being axially moved relative to the nozzle. A nozzle positioning system is also described herein.