A pressure relief valve is disclosed with a first stage valve that is in series with a second stage valve, with an enclosed cavity between the first stage valve and the second stage valve. The first stage valve relieves pressure from an enclosure into the enclosed cavity between the stages, when the pressure is above a cracking pressure of the first stage valve. The second stage relieves pressure from the enclosed cavity when the pressure is above the cracking pressure of the second stage valve.

Check valve are disclosed having a primary seal and a secondary seal, where the primary and secondary seals resist movement of a fluid through the check valve, and the secondary seal can provide a backup seal in an instance where the check valve does not function as intended. The primary and secondary seals can be formed by first and second sealing ridges, respectively, and a valve body can be positioned within the check valve, between a valve support, the first sealing ridge, and a second sealing ridge. The valve body is configured to move relative to the first and second sealing ridges, and can have a position wherein a portion of the valve body is engaged against any of the first and second sealing ridges.

Check valve are disclosed having a primary seal and a secondary seal, where the primary and secondary seals resist movement of a fluid through the check valve, and the secondary seal can provide a backup seal in an instance where the check valve does not function as intended. The primary and secondary seals can be formed by first and second sealing ridges, respectively, and a valve body can be positioned within the check valve, between a valve support, the first sealing ridge, and a second sealing ridge. The valve body is configured to move relative to the first and second sealing ridges, and can have a position wherein a portion of the valve body is engaged against any of the first and second sealing ridges.

A valve for a positive displacement pump, a valve seat, a valve body for use therewith, and a pump comprising such a valve are described. The valve comprises a valve body and a valve seat each having engagement surfaces which are configured, in use, to at least partially engage with one another when the valve is in a closed position to thereby mitigate fluid flow therethrough. The valve body is movable, in use, relative to the valve seat along a linear path of motion from the closed position to an open position, wherein at least a peripheral portion of the engagement surface of the valve body extends at an obtuse angle relative to the linear path of motion in the direction of motion from the closed position to the open position and wherein the length of the peripheral portion is at least 13% of the length of the engagement surface.

Check valve are disclosed having a primary seal and a secondary seal, where the primary and secondary seals resist movement of a fluid through the check valve, and the secondary seal can provide a backup seal in an instance where the check valve does not function as intended. The primary and secondary seals can be formed by first and second sealing ridges, respectively, and a valve body can be positioned within the check valve, between a valve support, the first sealing ridge, and a second sealing ridge. The valve body is configured to move relative to the first and second sealing ridges, and can have a position wherein a portion of the valve body is engaged against any of the first and second sealing ridges.

A valve for a positive displacement pump, a valve seat, a valve body for use therewith, and a pump comprising such a valve are described. The valve comprises a valve body and a valve seat each having engagement surfaces which are configured, in use, to at least partially engage with one another when the valve is in a closed position to thereby mitigate fluid flow therethrough. The valve body is movable, in use, relative to the valve seat along a linear path of motion from the closed position to an open position, wherein at least a peripheral portion of the engagement surface of the valve body extends at an obtuse angle relative to the linear path of motion in the direction of motion from the closed position to the open position and wherein the length of the peripheral portion is at least 13% of the length of the engagement surface.

A valve seat for use within a hydraulic fracturing pump includes a first portion including a strike face for interacting with a reciprocating component associated with the valve seat. The valve seat also includes a second portion having a recess to receive at least a portion of the first portion, the first portion being coupled to the second portion using a hybrid joining method that includes both a mechanical fastener to secure the first portion to the second portion and a joining process to secure the first portion to the second portion.

Check valve are disclosed having a primary seal and a secondary seal, where the primary and secondary seals resist movement of a fluid through the check valve, and the secondary seal can provide a backup seal in an instance where the check valve does not function as intended. The primary and secondary seals can be formed by first and second sealing ridges, respectively, and a valve body can be positioned within the check valve, between a valve support, the first sealing ridge, and a second sealing ridge. The valve body is configured to move relative to the first and second sealing ridges, and can have a position wherein a portion of the valve body is engaged against any of the first and second sealing ridges.

A valve for conveying fluid has a closed position and an open position and comprises a body, a valve seat disposed in the body, a holder disposed in the body, and a valve seat disc. The valve seat comprises one or more inner surfaces and an outer surface, and the one or more inner surfaces define an inner void. The valve seat disc is connected to and movable with the holder between a first position in which the valve seat disc sealingly engages the outer surface of the valve seat and a second position in which the valve seat disc is disengaged from the outer surface of the valve seat. The valve is in the closed position when the valve seat disc is in the first position and the valve is in the open position when the valve seat disc is in the second position.

A valve seat for a valve assembly for a high-pressure fluid pump is disclosed. The valve assembly includes a valve body, and a valve seat fabricated of a first material. The valve seat has a generally a tubular body having an annular collar having an outer diameter surface extending beyond the outer diameter surface of the tubular body, and an annular insert fabricated of a second material more durable than the first material and affixed to form an inner diameter surface of the collar, the insert forming an annular sealing surface against which the valve body abuts when in a closed position. The insert forms an annular ledge edge at its inner diameter surface that is offset from the inner diameter surface of the tubular body to form an annular chamfered edge.