An end of a first land has a step difference recessing inward of a radial direction of the first land from the edge portion. The step difference has an end point opposite to the edge portion. A throttle portion protrudes from the start point in an axial direction, and includes an outer-peripheral corner (protrusion round portion) having a curved surface protruding in the axial direction and in the radial direction. When an inlet opening starts to be slightly opened, since a hydraulic fluid is throttled when flowing through a second gate opened between a corner of a sleeve and the protrusion round portion, a rapid increasing of a flow quantity of the hydraulic fluid and an instability of a control of the hydraulic fluid can be suppressed.

A servo regulator includes servo piston, a first pressure chamber and a second pressure chamber, a spool, a biasing member provided on an outer periphery of the spool and configured to bias the spool, a first support portion configured to support one end portion of the biasing member when the spool is moved to a first direction where the pressure in the first pressure chamber is raised, and a second support portion configured to support other end portion of the biasing member when the spool is moved to a second direction where the pressure in the second pressure chamber is raised, wherein at least one of the first support portion and the second support portion is detachably provided on the spool.

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 safety valve for a hydrocarbon wellbore includes a valve housing; a tubular valve member having an axially extending tube wall; and an operating mechanism for operating the valve member. The housing has a passage extending from a lower opening to an upper opening. The tube wall has one or more radial inlet apertures therethrough. The lower end part of the tube wall is closed. The valve member is axially movable in the passage between a flow position and a blocking position. In blocking position, the valve member is retracted in the housing such that the inlet apertures lie inside the housing and fluid flow between the lower opening and upper opening is prevented by the closed lower end part of the valve member. In the flow position, the valve member projects below the housing such that the one or more radial inlet apertures lie outside the housing.

A solenoid spool valve including a spool valve having a sleeve provided with a supply pressure port, a control pressure port, an exhaust port and a spool supported in the sleeve for axial displacement within the sleeve; and an electromagnetic actuator for providing an axial drive force to the spool in a first axial direction; wherein the spool has a first piston with a first land for opening/closing the supply pressure port and a second piston with a second land for opening/closing the exhaust port, wherein the first piston has a larger piston face surface area in fluid communication with the control pressure port than does the second piston.

A control device selectively fluidically connects and disconnects fluid connection points (A, P, T) by a valve (5), which controls fluid-conducting connection channels (55, 57, 59) extending between the connection points (A, P, T). The connection channels are arranged in a control block (3), into which the valve (5) is at least partially inserted. Proceeding from the respective fluid connection points (A, P, T), the connection channels (55, 59, 57) connected to the fluid connection points extend in parallel to each other until the connection channels lead into a respective control chamber (49; 53, 51). The valve (5) is retained in a receptacle (39) separating two adjacently arranged control chambers (49, 51) from each other.

A hydraulic valve including a valve housing including a longitudinal axis, a receiving opening extending along the longitudinal axis, a first flow through opening of a supply connection, a second flow through opening of an operating connection, a third flow through opening of a tank connection, wherein the first flow through opening, the second flow through opening and the third flow through opening are configured at least partially flowable by a hydraulic fluid flowing through the valve housing, and a valve piston with a control groove which valve piston is axially displaceable in the valve housing in the receiving opening along the longitudinal axis, wherein the flow forces of the hydraulic fluid imparted upon the valve piston are oriented away from a first switching position of the hydraulic valve where the hydraulic fluid flows from the first flow through opening into the second flow through opening.

The invention relates to a flow control valve adapted for use as a flow-dividing and flow-combining valve in hydraulic devices, comprising: a valve body having a first longitudinally extending bore, an outer spool slidably positioned within the bore, the outer spool having an axially extending passageway, a pair of axially extending inner spools slidably positioned within the passageway, the valve body having a first port and a pair of second ports, the outer spool having at least a first opening communicating with the first port and with the passageway, and at least two pairs of second openings therethrough. At least one second opening of each pair is of non-constant longitudinal section narrowing from the outer face of the outer spool on at least a part of the thickness of the second opening, so that a lateral side of the second opening offers an obstacle where a part of the fluid flow entering the second opening crashes before entering the inner spool.

A valve body defines a work passage, a high-pressure channel fluidly connected to the work passage, a tank passage, and a cavity disposed between the high-pressure channel and the tank passage. The cavity fluidly connects the high-pressure channel and the tank passage. The cavity is defined at least in part by a first portion within which a relief valve threadedly engages, a second portion disposed adjacent to the high-pressure channel, and an annulus interposed between the first portion and the second portion. The annulus fluidly connects to the tank passage. A surface area of the relief valve exposed to the annulus is greater than a cross-sectional area of the high-pressure channel.

An emergency shut-off device shuts off supply of control oil to a trip-and-throttle valve of a steam turbine and closes the trip-and-throttle valve in an emergency. The emergency shut-off device includes: a cylinder; a piston that slides into the cylinder; a spring that applies a biasing force to the piston; a plurality of piston valves disposed on the piston; and a plurality of chambers that are formed by the piston valves. The control oil is supplied to and drained from the plurality of chambers, and a sliding surface of each of the piston valves has a groove to leak the control oil in a corresponding one of the chambers to another one of the chambers that is adjacent to the corresponding chamber in an axis direction.