Servo-valve that drives an actuator by using a fluid. The servo-valve includes a nozzle having a discharge edge forming an outline of a discharge port from which the fluid is discharged and a tapered inner wall growing narrower toward the discharge edge, and a receiver that is provided with a flow path into which the fluid discharged from the discharge port flows. The nozzle is displaced in a direction different from the fluid discharge direction. The flow path extension direction is inclined with respect to a direction orthogonal to an inflow surface facing the nozzle by an angle α. A taper angle determined by the tapered inner wall is larger than twice the angle α. With such a configuration, the component of flow force exerted from the fluid on the tapered inner wall decreases. Since the nozzle can be quickly displaced, response speed of the actuator is improved.

A solenoid for a bleed valve includes a solenoid body with an actuation fluid passage, a bleed valve passage, and a drive fluid chamber. A main armature is disposed within the solenoid body and is movable between open and closed positions, the actuation fluid passage being in fluid communication with the control outlet in the open position, the actuation fluid passage being fluidly isolated from the bleed valve passage in the second position. A pilot armature is disposed within the solenoid body, is movable relative to the main armature, and is operably coupled to the main armature by the drive fluid chamber to move the main armature between the open and closed positions by controlling issue of a drive fluid into and out of the drive fluid chamber.

An electropneumatic solenoid valve for a pneumatically-actuated field device can include air channels, a flapper valve member, an electromagnetic controller, and a spring. An air supply channel, air dispensing channel and air exhaust channel can be mound into an air chamber. The flapper valve member can include a closure element arranged on an axial control direction and be engageable with a delimitation interior wall mouth of one of the air channels such that the flapper valve member is arranged with a circumferential axial distance to the delimitation interior wall. The electromagnetic controller can displace the flapper valve member in the axial control direction to ventilate/exhaust the air dispensing channel. The spring can bias the flapper valve member into a closed position to close closing the one of the air channels. The flapper valve member can be float-mounted in an unguided configuration except for spring within the air chamber.

A valve body in each of heat medium flow switching devices has an open portion. When the length from a connection between a first passage pipe and a third passage pipe to a connection between a second passage pipe and the third passage pipe is defined as a casing passage width, a valve body passage width of the open portion in a direction substantially perpendicular to the axis of the valve body is smaller than the casing passage width.

A valve assembly may comprise: a housing cap; a valve housing having an inlet port, an outlet port, and a pilot pressure inlet port, the inlet port disposed axially opposite the housing cap; a poppet defining an axial surface and a radially outer surface, the poppet including a first radial groove disposed in the radially outer surface; a first dynamic radial seal disposed in the first radial groove and in intimate contact with a radially inner surface of the valve housing, the first dynamic radial seal configured to maintain unobstructed contact with the radially inner surface of the valve housing in response to the poppet translating axially from an open position to a closed position.

Methods for testing the operability of a safety valve, as well as a solenoid valve for triggering a safety valve, and corresponding devices are proposed. The safety valve has a solenoid valve which is used to vent the pneumatic actuator in a safety case. Initially, a safety case is triggered. The position course of the valve member is recorded, and the time required until the safety position is reached is compared with a reference value. From this, it can be reliably concluded whether the assumption of the fail-safe position was caused by the solenoid valve or by the positioner. The measured values of pressure sensors can also be taken into account and allow further diagnostics to be carried out if operability is not assured. If the result of the test is positive, maintenance intervals can be optimized.

A switching valve device for switching an intermediate flow path through which a fluid flows from an inlet to an outlet includes: a first valve which switches a flow path extending from the inlet to one of two flow paths; and a second valve which is provided on a downstream side of the first valve and switches the intermediate flow path by a differential pressure generated by depressurization in an external flow path Lout connected to the intermediate flow path connected to one of the two flow paths.

An electro-hydraulic proportional valve includes: a valve core; a valve sleeve, sleeving an outside of the valve core; a valve body, sleeving an outside of the valve sleeve and fixedly connected to the valve sleeve; a left end cap, covering an end of the valve body, a left sensitive cavity being defined by the left end cap, the valve body, and the valve sleeve; a right end cap, covering the other end of the valve body, a right sensitive cavity being defined by the right end cap, the valve body, and the valve sleeve; a driving mechanism disposed out of the valve body; and a transmission mechanism connected to the driving mechanism and the valve core.

A switching valve device for switching an intermediate flow path through which a fluid flows from an inlet to an outlet includes: a first valve which switches a flow path extending from the inlet to one of two flow paths; and a second valve which is provided on a downstream side of the first valve and switches the intermediate flow path by a differential pressure generated by depressurization in an external flow path Lout connected to the intermediate flow path connected to one of the two flow paths.

Passage forming blocks of a first pilot valve and a second pilot valve each include a supply passage, which opens in a first surface and a second surface and is connected to a valve chamber, a first output passage, which opens in the first surface and are connected to the valve chamber, and a second output passage, which opens in the first surface. Further, the passage forming blocks each include an output passage connecting recess. The output passage connecting recess is provided in a section of the second surface that overlaps with an opening region of the first output passage, which opens in the first surface, and is connected to the second output passage. The first output passage of the first pilot valve is connected to the second output passage of the second pilot valve via the output passage connecting recess of the second pilot valve.