An example valve includes: (i) a housing defining a first longitudinal cavity therein; (ii) a sleeve disposed in the first longitudinal cavity coaxial with the housing, where the sleeve defines (a) a first port at an end of the sleeve, (b) a second port disposed on an exterior peripheral surface of the sleeve, and (c) a second longitudinal cavity therein, where an interior peripheral surface of the sleeve defines a first portion that is tapered at a particular angle and a second portion adjacent to the first portion, where the second portion has two edges forming a corner that defines a seat; and (iii) a poppet mounted within the second longitudinal cavity and configured to move axially therein.

An example valve includes: (i) a housing defining a first longitudinal cavity therein; (ii) a sleeve disposed in the first longitudinal cavity coaxial with the housing, where the sleeve defines (a) a first port at an end of the sleeve, (b) a second port disposed on an exterior peripheral surface of the sleeve, and (c) a second longitudinal cavity therein, where an interior peripheral surface of the sleeve defines a first portion that is tapered at a particular angle and a second portion adjacent to the first portion, where the second portion has two edges forming a corner that defines a seat; and (iii) a poppet mounted within the second longitudinal cavity and configured to move axially therein.

A valve includes a valve body, an inlet orifice in fluid communication with a first fluid volume, an outlet aperture in fluid communication with a second fluid volume and in selective fluid communication with the inlet orifice by a first fluid flow path, an activation member axially movable relative to the valve body, and a plunger axially movable within the valve body. The plunger includes an aperture therethrough defining a second fluid flow path between the first and second fluid volumes. The valve is operable in a first mode in which fluid flow is only permitted along the first fluid flow path in response to manual actuation of the activation member. The valve is operable in a second mode in which fluid flow is only permitted along the second fluid flow path when a pressure difference between the first and second fluid volumes reaches a predetermined value.

A port closure system (20) including a retention structure (22), and a valve (24). The retention structure (22) includes a port (28) for establishing communication between an exterior environment (30) and interior volume (32) that can receive a fluent substance. The valve (24) includes a flexible, resilient, self-closing, slit-type valve head (36) with an orifice that is normally closed in an unconstrained condition. The port (28) has a laterally inwardly facing engaging surface (34) and the valve has a laterally outwardly facing peripheral surface (54) that is compressed laterally inwardly by engagement with the surface (34) to increase the resistance of the normally closed orifice to opening when the head (36) is subjected to a pressure differential. The system (20) further includes an annular flange (62) located to extend over at least a portion of an exterior side (38) of the valve head (36) to limit movement of the valve head (36) towards the exterior environment (30).

A valve (61) for enabling release of pressurized steam from a pressure vessel has a displaceable closure member (67) which is maintained in its closed disposition by exposure to the pressure of the steam within the pressure vessel. The closure member (67) is displaced between its closed disposition and an open disposition by a double-acting actuator (69), suitably an air-driven piston/cylinder device, the closure member (67) being preferably mounted at one axial end of a spindle (68) extending between the closure member (67) and the actuator (69). The closure member (67) is suitably mounted for substantially metal-to-metal contact with a valve seat portion (63), without interposition of any sealing element, preferably for substantially vertical displacement between its closed and dispositions.

Hydraulic fluid release valve assemblies are described herein. The hydraulic fluid release valve assemblies may include a hydraulic unit base with a hydraulic fluid return channel and a hydraulic fluid release valve that is at least partially inserted in the hydraulic fluid return channel. The hydraulic fluid release valve assembly may further include a driving assembly to contact with the hydraulic fluid release valve to apply a pushing force on the hydraulic release valve to open the hydraulic fluid release valve, and an electrically powered driver connected to the driving assembly, the electrically powered driver, when actuated, causes the driving assembly to move to apply the pushing force to the hydraulic fluid release valve.

A pneumatic valve comprises a housing with an air chamber having supply, connecting and discharge openings. An actuator with a movable closing element is arranged in the housing, featuring a plunger, which projects through the discharge opening with a plate and a first sealing element for closing the discharge opening with an elastic element which, in the activated state, presses said sealing element against the discharge opening The actuator is in the form of an SMA actuator, wherein the actuator element is configured to, in a non-energized state, bring the actuating element to a first state in which it presses the plunger against the supply opening, and to, in an energized state, bring the actuating element to a second state in which the actuating portion does not exert any force on the plunger, wherein a second sealing element is arranged in the air chamber and functions as a check valve.

A relief valve for a backflow preventer includes a plunger, a lock nut, and a seal. The plunger has a female fastening section and a first seal engagement surface. The lock nut has a male fastening section and a second seal engagement surface. The male fastening section is received by the female fastening section to bring the first seal engagement surface toward the second seal engagement surface. The seal is positioned between the first seal engagement surface and the second seal engagement surface.

Hydraulic fluid release valve assemblies are described herein. The hydraulic fluid release valve assemblies may include a hydraulic unit base with a hydraulic fluid return channel and a hydraulic fluid release valve that is at least partially inserted in the hydraulic fluid return channel. The hydraulic fluid release valve assembly may further include a driving assembly to contact with the hydraulic fluid release valve to apply a pushing force on the hydraulic release valve to open the hydraulic fluid release valve, and an electrically powered driver connected to the driving assembly, the electrically powered driver, when actuated, causes the driving assembly to move to apply the pushing force to the hydraulic fluid release valve.