A pressure relief valve includes a valve body including a monitored pressure inlet leading to a monitored pressure region, a piston having a shear seal bore and a surface facing the monitored pressure region, a vent passage and a the shear seal assembly comprising a seal plate having a sealing surface thereon, and the shear seal assembly includes a sealing surface facing the seal plate and having a first annular area, and a first surface having an annular surface area at least twice as large as the first area of the sealing surface, the first surface facing away from the first area, and a biasing seal in contact with the first surface.

A valve includes a first body having an inlet and a ledge surrounding the inlet at a location inwardly of the body, a second body having an outlet and a poppet bore having a circumferential poppet bore surface, a poppet located in the poppet bore and having a sealing face, the sealing face facing the ledge of the first body, and a sealing arrangement which includes a circumferential support surface, a compressible seal ring having an uncompressed free state and a compressed state, an outer circumferential surface, and an inner circumferential surface facing the circumferential support surface, and a split ring disposed over the outer circumferential surface of the compressible seal ring, the compressible seal ring in a compressed state between the split ring and the inner circumferential surface.

A pressure relief valve includes a valve body including a monitored pressure inlet leading to a monitored pressure region, a piston having a shear seal bore and a surface facing the monitored pressure region, a vent passage and a the shear seal assembly comprising a seal plate having a sealing surface thereon, and the shear seal assembly includes a sealing surface facing the seal plate and having a first annular area, and a first surface having an annular surface area at least twice as large as the first area of the sealing surface, the first surface facing away from the first area, and a biasing seal in contact with the first surface.

A chemical injection valve can include a valve stem, flow between sections of a flow passage being prevented and permitted in respective closed and open positions of the valve stem, a resilient primary seal that prevents flow through an annular gap surrounding the valve stem in the closed position, and a bypass passage in communication with the annular gap and a flow passage section, and in communication with another flow passage section in the open position. A chemical injection system can include a chemical treatment pumped through a chemical injection valve and into an interior of a tubular string, and the chemical injection valve including a valve stem and a bypass passage extending between a flow passage section and an annulus surrounding the valve stem, the annulus being positioned longitudinally between a resilient primary seal and a metal secondary seal.

A valve includes a valve housing, a piston, a support element, and a spring. The piston and the valve housing are arranged coaxially to each other on an imaginary valve axis. The piston is received in the valve housing in an axially movable manner against the spring force of the spring. The spring is supported on the support element and on the piston. The valve housing is provided with a first opening through which a fluid can flow and which can be closed by a piston base of the piston. The valve housing is provided with a second opening which can be at least partly closed by a piston casing of the piston and through which the fluid can flow. The piston casing extends outwards from the piston base in the axial direction of the support element and surrounds the valve axis.

A safety valve has a valve seat (8) and a sealing body (12) movable relative to the valve seat (8) along a first axis (X), the sealing body being biased with a holding force (F.sub.H) along this first axis (X) in the direction of the valve seat (8). A sealing element (24) is arranged on the sealing body (12) in a manner such that with one first side (32) it can be brought into sealing contact with the valve seat (8). A pressure surface situated on a second side (34) of the sealing element (24), which is opposite to the first side (32), is connected via a pressure channel (40) to a pressure region (4) surrounded by the valve seat (8). The sealing body (12) has a contact surface (25) coming to bear on a rest surface (10) in the closed condition of the safety valve.

An inlet port provides a fluid entrance to a body. A chamber has an inner surface. An outlet port is in fluid communication with the chamber and provides a fluid exit from the body. The piston is moveable within the chamber between a first set position, in which the inlet port is not in fluid communication with the outlet port, and a second open position, in which the inlet port is in fluid communication with the outlet port through the chamber. A seal guard is slidably disposed within the chamber. The seal guard is moveable between a first seal-guard position and a second seal-guard position in which the seal guard shields the seal. The seal guard is in the first seal-guard position when the piston is in its first set position and in the second seal-guard position when the piston is in its second open position.

A pressure-limiting valve for use in a gas line conveying a gas that includes aerosols. The pressure-limiting valve has a movable valve body, a valve seat, and a compressible coalescing medium placed therebetween. The valve body has passages and nozzle openings and the valve seat has through-holes. In the closed position, the valve functions in separator mode and in the fully open position, in impactor mode. The pressure-limiting valve according to the invention provides a more sensitive response to varying flow conditions, due to deviating surface profiles of the valve seat and coalescing medium, which provide intermediate stages of separator and impactor modes as a function of the volume of flow.

A pressure relief valve (PRV) is provided. The PRV includes a first housing part and a second housing part. The first housing part includes first major and minor surfaces and a first deformed corner at an intersection of the first major and minor surfaces. The second housing part includes second major and minor surfaces and a second deformed corner at an intersection of the second major and minor surfaces. The first and second housing parts are disposed with the first and second minor surfaces facing oppositely at a distance to define a metering hole. The first and second deformed corners are deformed by a coining ball to cooperatively form a coined seat at the metering hole for seating and re-seating a sealing ball. The first and second deformed corners have respective radii of curvatures resulting from deformation which are larger than that of the sealing ball.

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.