In an exemplary method of monitoring performance of a fluid driven actuator for a valve, pressurized fluid is supplied through an actuator supply line to an inlet port of the actuator during a first time period to operate the actuator. Changes corresponding to a fluid flow condition in the actuator supply line are measured during the first time period, and the measured changes are analyzed to identify a non-compliant condition in at least one of the valve and the actuator. An output communicating the identified non-compliant condition is then generated.

A stage assembly (10) includes a stage (14), and a fluid actuator assembly (24) that moves the stage (14). The fluid actuator assembly (24) includes a piston housing (32) that defines a piston chamber (34); (ii) a piston (36) that separates the piston chamber (34) into a first chamber (34A) and a second chamber (34B); (iii) a supply valve (38C) that controls the flow of the working fluid (40) into the first chamber (34A); and (iv) an exhaust valve (38D) that controls the flow of the working fluid (40) out of the first chamber (34A). The supply valve (38C) has a supply orifice (250G) having a supply orifice area, and the exhaust valve (38D) has an exhaust orifice (352G) having an exhaust orifice area. Moreover, the supply orifice area is different from the exhaust orifice area. Further multiple valves of different sizes can be used in combination for the supply and exhaust for each chamber (34A), (34B).

A hydraulic system includes a hydraulic pump to output an operation fluid, first and second hydraulic devices to be operated by the operation fluid, first and second control valves to control the first and second hydraulic device, respectively, first and second communication tubes connecting the first hydraulic device to the first control valve, a supply fluid tube connecting the first control valve to the second control valve, the supply fluid tube being configured to supply the return fluid to the second control valve, first and second connection fluid tubes disposed on the first control valve, a discharge fluid tube connected to the first control valve, first and second branching fluid tubes branched from the first and second connection fluid tubes, respectively, first and second throttles disposed on the first and second branching fluid tubes, respectively, the second throttle being smaller than the first throttle.

A hydraulic pressure amplifier arrangement (1) is described comprising a supply port (A1), a pressure outlet (A2) connected to the supply port via check valve means (3), a tank port (B1), an intensifier section (5) having a high pressure piston (6) in a high pressure cylinder (7) which is connected to the pressure outlet (A2), a low pressure piston (8) in a low pressure cylinder (9) and connected to the high pressure piston (6), an intermediate space (11) between the high pressure piston (6) and the low pressure piston (8), a control valve (12) controlling a pressure in the low pressure cylinder (9), and a feeder arrangement of the intensifier section (5) including an input connection (19) connected to the supply port (A1) and a return connection (20) connected to the tank port (B1). Such a pressure amplifier arrangement should have a simple construction. To this end the feeder arrangement (19, 20) comprises throttling means (21).

A passive fluidic valve for fixed flow rate distribution comprising: a hollow valve body; a valve member for blocking a passage to one of the two outlets; and communications to impose the pressure of the upstream and downstream cavities at the ends of the valve member. The valve body further comprises: an inlet; a first outlet comprising a first restriction delimiting an upstream cavity and a downstream cavity; a second outlet comprising a second restriction delimiting an upstream cavity and a downstream cavity; and a first and a second cavity. The valve member further comprises: a first end in the first cavity delimiting a first and a third chambers, and a second end in the second cavity delimiting a second and a fourth chambers.

A fluid pressure control device includes a switching valve, a main pilot passage and a sub pilot passage, the switching valve is configured to be switched to the open position when the working fluid is supplied to the pilot chamber, and to be switched to the throttled position with opening on the downstream side of the switching valve in the neutral passage, and the sub pilot passage is provided with a throttle portion and a check valve in parallel in the throttle portion.

Hydraulic systems and methods comprising a source of hydraulic pressure; a hydraulic load; and an energy recovery circuit. The source of hydraulic pressure is fluidly connected to the hydraulic load through a first hydraulic channel with an orifice. The energy recovery circuit includes a recovery channel which is fluidly connected at its first end to the orifice on the side of it which is connected to the source of hydraulic pressure, and which is fluidly connected at its second end to a hydraulic motor.

A hydraulic system may include a reservoir of hydraulic fluid, a hydraulic pump, a directional control valve, a hydraulic work loop, a bypass valve, and a hydraulic motor, as well as a plurality of hydraulic conduits interconnecting such components. When excessive hydraulic backpressures are encountered, the system may employ one or more bypass valves and one or more bypass conduits to automatically, and in an on-demand manner, return some or all of the hydraulic fluid from the hydraulic motor to the hydraulic reservoir without the hydraulic fluid passing through flow constrictions causing the excessive hydraulic backpressures.

The present invention provides a switching valve comprising: a housing including a first port, a second port, and a third port; a valve element configured to be movable in the housing so as to selectively allow one of the first port and the second port to communicate with the third port in accordance with a pressure difference between the first port and the second port; and a pressing member configured to press the valve element toward a side of the first port.

A temperature control fluid is introduced through a first port. The temperature control fluid introduced into the first port is discharged through a second port. A piston is configured to be moved by a pressure to open or close a path connecting the first port and the second port. A pressure control space is provided at at least one side of a moving direction of the piston when the path is opened or closed. Air is supplied into the pressure control space through a third port. A leak portion communicates with the pressure control space, and allows the air supplied into the pressure control space to leak therethrough.