A valve device includes: a poppet that is formed in a hollow shaft shape except for a leading end, has a tapered closure part at the leading end and a side hole passing through a wall of the hollow shaft-shaped part, and rotates around a shaft center thereof during opening and closing actions; and a valve seat having a sloped seat surface with which the closure part of the poppet comes into contact when closing the valve device. The closure part of the poppet or the seat surface of the valve seat, whichever has a higher hardness, has a cut mark of the opposite direction from a direction of rotation of the poppet around the shaft center that occurs during the valve closing action.

A switching membrane for a pressure control valve has a plate-shaped flat body with a central area and a bending area surrounding the central area. The central area is provided with a closure area. For switching the switching membrane, the central area can be moved back and forth by a bending movement of the bending area in a direction transverse to an extension of the central area. At least the bending area is made of fluorocarbon rubber. A pressure control valve, especially for crankcase ventilation, is provided with a valve housing that has a housing cover and further is provided with a valve seat. A switching membrane as described above is disposed in the valve housing and switches at pressure differences of at most 500 mbar to release or shut off a flow of fluid at the valve seat.

The seal made between two surfaces is enhanced by forming a coating, such as a self-assembled monolayer of a functionalized fluorinated macromolecule, on one or both of the surfaces.

The seal made between two surfaces is enhanced by forming a coating, such as a self-assembled monolayer of a functionalized fluorinated macromolecule, on one or both of the surfaces.

A force actuated modulating control valve such as a direct acting solenoid valve or pilot actuated bellows valve with a knife edge seat so that the metering location on the seat is at the very outer diameter. In one embodiment, a portion of the valve seat outside of the metering edge is removed to substantially the outside diameter to reduce contact with high velocity fluid flow. In certain embodiments, a flow shield may be positioned just outside of the metering edge of the seat to prevent the high velocity fluid from circulating toward parts of the spool assembly. In some embodiments, the flow shield may be fixed to the body of the instrument so all fluid forces are transmitted to the body. Embodiments of the force actuated modulating control valve may be employed in a mass flow controller for controlling fluid flow.

A force actuated modulating control valve such as a direct acting solenoid valve or pilot actuated bellows valve with a knife edge seat so that the metering location on the seat is at the very outer diameter. In one embodiment, a portion of the valve seat outside of the metering edge is removed to substantially the outside diameter to reduce contact with high velocity fluid flow. In certain embodiments, a flow shield may be positioned just outside of the metering edge of the seat to prevent the high velocity fluid from circulating toward parts of the spool assembly. In some embodiments, the flow shield may be fixed to the body of the instrument so all fluid forces are transmitted to the body. Embodiments of the force actuated modulating control valve may be employed in a mass flow controller for controlling fluid flow.

In a valve apparatus, an annular contact portion made of elastic material is provided on a valve portion of a valve plug. A plurality of annular grooves are formed on a proximal end surface of a valve seat member which abuts against the contact portion. The annular grooves are formed around a communication hole through which fluid flows. The annular grooves have different diameters, and are concentric with one another.

A valve assembly (10) for large scale irrigation including a valve body (20) and a valve head (40). The valve head is adapted to reciprocally travel along a longitudinal axis, supported by a longitudinally aligned shaft (60) inside the valve body. The valve head includes a wall (41) terminating in a peripheral sealing contact surface (42), the wall extending inwardly from the peripheral contacting surface.

An internal engagement structure of a housing for a water control valve, the water control valve including the housing and a valve assembly, and the housing contains: a holder and a cover. The holder is configured to accommodate the valve assembly, and the cover is covered on the holder. The holder includes two opposite receiving grooves, two locking recesses formed on two lower ends of the two opposite receiving grooves respectively and communicating with the holder, and two tilted guide faces arranged on two upper ends of the two opposite receiving grooves respectively. The cover includes two opposite retainers extending downward from a bottom thereof and corresponding to the two opposite receiving grooves respectively, two hooks formed on two lower ends of the two opposite retainers respectively, and two cutouts defined above the two hooks respectively and configured to accommodate the two tilted guide faces respectively.

A centric butterfly valve (1) in which top and bottom boss surfaces (19, 29) are formed to be spherical, an outer peripheral end of the blade portion of the valve disk (24) is formed to be an M-shaped section part (29) with round-shaped apex parts (27) and a round-shaped valley part (28) smoothly linked, and the centric butterfly valve has a valve disk (3) having an extended part (41) obtained by successively and slightly extending the spherical surface of each of the top and bottom boss surfaces (19, 20) to a blade portion (40) side.