A chemical injection valve can include a valve stem reciprocably disposed relative to a primary seal, and a variable flow restrictor upstream of the primary seal relative to a direction of flow through the chemical injection valve. The variable flow restrictor restricts the flow when the valve stem is disengaged from the primary seal. A chemical injection system can include a chemical treatment pumped through a chemical injection valve and into an interior of a tubular string in a well, the chemical injection valve including a valve stem, a primary seal sealingly engaged with the valve stem in a closed position and disengaged from the valve stem in an open position, and a flow restrictor that restricts the flow of the chemical treatment downstream from the primary seal in the open position.

A valve includes a valve body having an inlet for fluid communication with a space or source containing pressurised gas, and at least one outlet. A membrane is arranged between the inlet and the at least one outlet. A membrane puncturing element is arranged for movement between a retracted, inoperative position and an extended position in which it punctures the membrane. An actuating piston is operatively coupled to the membrane puncturing element for moving the membrane puncturing element between its retracted and its extended positions, the actuating piston being received in a piston bore of the valve body. The valve body also includes a cartridge receiving chamber for receiving a sealed actuating gas cartridge. A cartridge puncturing device is provided for puncturing the actuating gas cartridge. An actuating gas flow passage communicates actuating gas released from the actuating gas cartridge to the actuating piston bore upon puncturing the actuating gas.

The present disclosure provides a valve seat assembly for a fluid end of a hydraulic fracturing pump. The valve seat assembly includes a valve seat having a substantially cylindrical body defined along an axis. The valve seat has a first seat end and a second seat end with a through bore extending between the first and second seat ends. The cylindrical body has an inner cylinder surface and an exterior cylinder surface with an annular flange formed along the exterior cylinder surface adjacent the first seat end. The through bore expands from a first diameter to a second diameter adjacent the first seat end. The valve seat assembly further includes a leak detection notch formed in the exterior cylinder surface between the annular flange and the second seat end.

A valve assembly is provided, the valve assembly comprising a body that defines a fluid flow path between an inlet and an outlet with a frangible member between the inlet and the outlet across the fluid flow path so as to block fluid flow The valve assembly also includes means for rupturing the frangible member, means for biasing the rupturing means into contact with the frangible member and means for retaining the rupturing means away from the frangible member. A magnet is spaced apart from the retaining means a non-magnetic sleeve is disposed between the magnet and the retaining means. The non-magnetic sleeve block a magnetic field provided by the magnet. Also included are means for removing the non-magnetic sleeve, wherein, when the non-magnetic sleeve is removed, in use, the magnetic field attracts the retaining means to release the rupturing means to cause rupture of the frangible member.

A valve assembly includes a valve housing defining therein a fluid flow channel between a first end arranged to be connected to a source of pressurised fluid, and an outlet a frangible member disposed within and across the fluid flow channel, rupture means for rupturing the frangible member and biasing means for biasing the means for rupturing into contact with the frangible member to cause rupture thereof. The assembly also includes retaining means for retaining the rupture means out of contact with the frangible member to prevent rupture thereof and release means configured to release the retaining means to allow the biasing means to bias the rupture means into contact with the frangible member. The retaining means includes a bearing extending to engage the biasing means and hold it in a compressed state and the assembly includes also includes securing means for securing the bearing in the engaged state.

A valve assembly is disclosed that has a valve housing including a first axial end, a cap, a second axial end, and an airflow pathway extending from the first axial end towards the second axial end. The cap is positioned towards the second axial end. The valve housing includes an environmental opening configured for fluid communication with an outside environment, an enclosure opening towards the first axial end configured for fluid communication with an interior of an enclosure, and a film having an expansion diameter disposed in the valve housing laterally across the airflow pathway. The cap has an inner lateral surface and a piercing protrusion (having a piercing tip) extending from the inner lateral surface towards the first axial end. An axial distance is defined between the film and the inner lateral surface. A ratio of the axial distance to the film expansion diameter is at least 0.14.

A valve includes a valve body, an inlet in the valve body in fluid communication with the gas and an outlet in the valve body, and a rupture disc in fluid communication with and between the inlet and the outlet that prevents fluid communication between the inlet and the outlet. The valve also includes a piston that is urged by a gas from the gas source to rupture the rupture disc to allow fluid communication between the gas source and the outlet.

An arrangement for blocking/unblocking a fluid flow comprises: a component delimiting a fluid passage to conduct a fluid from a high pressure side to a low pressure side; a bursting disk at least indirectly attached to the component and separating the high and low pressure sides to close the fluid passage; a support element on the low pressure side, which supports the bursting disk to withstand a fluid pressure on the high pressure side that exceeds a nominal bursting pressure of the bursting disk but that is lower than a maximum pressure; and a controllable actuator actuatable for unblocking the fluid passage. To unblock the fluid passage, the actuator is arranged to destroy or damage the support element such that a fluid pressure on the high pressure side of the bursting disk exceeding the nominal bursting pressure causes the bursting disk to burst.

An improved burst disc assembly for use in pressure relief conduits for high vacuum and ultra-high vacuum containment vessels, the assembly having a body with inlet and outlet openings connected by an internal passage, a burst disc disposed within the internal passage and connected therein to hermetically isolate the inlet and outlet openings. The assembly further has a mounting structure connected to the body and outwardly extending therefrom that may be clamped between adjacent faces of a pair of metal seal flanges provided in the relief conduit to secure the assembly in position and hermetically seal the assembly in the conduit in a manner prohibit the passage of gas molecules from the surrounding environment into the containment vessel through the relief conduit. The mounting structure is formed from a soft metal material having substantially lower hardness value than that of the metal seal flange faces to enable adequate sealing. The connection between the mounting structure and the body further provides similar hermetic seal. Upon rupture of the burst disc, the assembly alone must be replaced while the metal seal flanges connecting the burst disc assembly to the containment vessel may be reused.

A pressure relief apparatus may include a pressure relief portion and a plurality of stages of indented grooves. The pressure relief portion may be provided with a first surface and a second surface arranged opposite to each other in a thickness direction thereof. The plurality of stages of indented grooves may be formed in the pressure relief portion in sequence in a direction from the first surface to the second surface, and among two adjacent stages of indented grooves, the stage of indented groove away from the first surface may be formed in a bottom surface of the stage of indented groove close to the first surface. The pressure relief portion may be provided with an opening area, and the indented grooves may be formed along an edge of the opening area.