A retarder control valve assembly and system for controlling speed of rail cars, utilizes cartridge valves carried in a manifold body including piping and pilot control apparatus, but no wearing surfaces, dynamic seals, or moving parts. The cartridge valves are replaceable without replumbing, and include all moving valve elements and dynamic seals. The valves each include a piston controlled poppet carried on a spool movable within a cartridge body to open and close the valve and supported to withstand high side loads. The pressure sensing and feedback to the retarder system controller is at the manifold, in a pressure spike attenuating circuit having a phase modulating capability to mimic retarder pressure remotely.

A retarder control valve assembly and system for controlling speed of rail cars, utilizes cartridge valves carried in a manifold body including piping and pilot control apparatus, but no wearing surfaces, dynamic seals, or moving parts. The cartridge valves are replaceable without replumbing, and include all moving valve elements and dynamic seals. The valves each include a piston controlled poppet carried on a spool movable within a cartridge body to open and close the valve and supported to withstand high side loads. The pressure sensing and feedback to the retarder system controller is at the manifold, in a pressure spike attenuating circuit having a phase modulating capability to mimic retarder pressure remotely.

A flow control valve including a main valve and a pilot valve for controlling a piston of the main valve. The pilot valve is controlled in part with relatively high pressure fluid ported from a high pressure port of a flow sensor and relatively low pressure fluid ported from a low pressure port of a flow sensor, and also controlled with a control fluid applied to a control plate acting on a compression spring to bias the pilot valve. The pressure in the control fluid is controlled by pressurizing a control fluid reservoir with a mechanism accessible from outside the valve and the piping in which the valve is installed. The flow sensor and the reservoir are preferably disposed within the flange of the valve.

A two-stage proportional control valve configured for use in a fluid system includes a valve body having a longitudinally extending valve body bore formed therethrough. A first stage microvalve is mounted within the valve body bore, and a second stage spool assembly is mounted within the valve body bore downstream of the microvalve. The second stage spool assembly includes a sleeve and a spool slidably mounted within the sleeve.

A change-over valve comprises a spool housed in a spool housing, and a pilot chamber facing at least an end of the spool. An axial passage is formed in the spool along the axial direction. While being connected to a pilot chamber, the axial passage communicates with a tank passage via a small hole having an opening on an outer periphery of the spool in accordance with displacement of the spool, to discharge the air in the pilot chamber to the tank passage. Since the axial passage is formed at a location offset from a center axis of the spool, a length of the small hole is shortened and the small hole is easily processed.

A change-over valve comprises a spool housed in a spool housing, and a pilot chamber facing at least an end of the spool. An axial passage is formed in the spool along the axial direction. While being connected to a pilot chamber, the axial passage communicates with a tank passage via a small hole having an opening on an outer periphery of the spool in accordance with displacement of the spool, to discharge the air in the pilot chamber to the tank passage. Since the axial passage is formed at a location offset from a center axis of the spool, a length of the small hole is shortened and the small hole is easily processed.

A high-flow valve arrangement in an electro-hydraulic safety control unit to discharge oil volume on instructions from a steam turbine safety system to actuate actuators to stop steam flow in steam turbines to shut-off, is provided. The valve includes a valve body with a flange having a plurality of spaced-apart through holes, a flat-circular plate cartridge and a valve housing configured to each other. The housing includes a chamber to accommodate oil volume; an inlet/outlet port to enable the oil volume to enter and exit therefrom, and a peripheral seat where the cartridge seats. The plate cartridge is capable of being moved upward, defining a very small stroke, upon the increase or decrease of the oil volume in the chamber to open and close the outlets defined via the plurality of spaced-apart through holes to enable and stop the fluid flow therefrom.

A high-flow valve arrangement in an electro-hydraulic safety control unit to discharge oil volume on instructions from a steam turbine safety system to actuate actuators to stop steam flow in steam turbines to shut-off, is provided. The valve includes a valve body with a flange having a plurality of spaced-apart through holes, a flat-circular plate cartridge and a valve housing configured to each other. The housing includes a chamber to accommodate oil volume; an inlet/outlet port to enable the oil volume to enter and exit therefrom, and a peripheral seat where the cartridge seats. The plate cartridge is capable of being moved upward, defining a very small stroke, upon the increase or decrease of the oil volume in the chamber to open and close the outlets defined via the plurality of spaced-apart through holes to enable and stop the fluid flow therefrom.

Slide flow distributor (100) comprising a motor (1) moving directly a spool (2) by means of a rod (8) of the motor, a charge chamber (3) of the working fluid, in central position, in fluid communication with two discharge branches (4, 5) and two delivery branches (6, 7) and characterized in that from the portion of the spool (2) proximal to the motor (I) it is provided a pneumatic servo-actuator (9) generating a force in the same direction and development of the axial force of the motor (I), with the result that the spool (2) is accelerated in a predetermined direction, said pneumatic servo-actuator comprising a profiled body (52), a plurality of balls (50) and corresponding elastic means (5 1) which press said plurality of balls (50) on the side surface of the profiled body (52).

Slide flow distributor (100) comprising a motor (1) moving directly a spool (2) by means of a rod (8) of the motor, a charge chamber (3) of the working fluid, in central position, in fluid communication with two discharge branches (4, 5) and two delivery branches (6, 7) and characterized in that from the portion of the spool (2) proximal to the motor (I) it is provided a pneumatic servo-actuator (9) generating a force in the same direction and development of the axial force of the motor (I), with the result that the spool (2) is accelerated in a predetermined direction, said pneumatic servo-actuator comprising a profiled body (52), a plurality of balls (50) and corresponding elastic means (5 1) which press said plurality of balls (50) on the side surface of the profiled body (52).