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.

A dynamic seal assembly is disclosed for use in a valve having an upstream pressure side and a downstream pressure side, the dynamic seal assembly including an annular seal member having a generally C-shaped cross-section and including opposed upstream and downstream legs defining an internal cavity with an opening facing toward the upstream pressure side of the valve, wherein the upstream leg has a radial length that is greater than a radial length of the downstream leg and includes a retaining foot that extends angularly away from the upstream leg in an upstream direction at an angle of between about 0° and 90°, and a metallic spring is disposed within the internal cavity of the seal member for providing a constant sealing force to the seal member.

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.

A hydraulic control apparatus includes an output-side oil passage into which oil from a first oil passage and oil from a second oil passage flow, and a pressure regulating check valve regulating a hydraulic pressure in the second oil passage. The pressure regulating check valve includes first and second elastic portions housed in a spool hole between a valve body and a bottom of the spool hole. A natural length of the second elastic portion is shorter than a distance between the valve body and the bottom when the valve body closes an inflow hole. The second elastic portion applies an elastic force to the valve body in a state in which the valve body opens the inflow hole.

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 hydraulic control apparatus includes an output-side oil passage into which oil from a first oil passage and oil from a second oil passage flow, and a pressure regulating check valve regulating a hydraulic pressure in the second oil passage. The pressure regulating check valve includes first and second elastic portions housed in a spool hole between a valve body and a bottom of the spool hole. A natural length of the second elastic portion is shorter than a distance between the valve body and the bottom when the valve body closes an inflow hole. The second elastic portion applies an elastic force to the valve body in a state in which the valve body opens the inflow hole.

A dynamic seal assembly is disclosed for use in a valve having an upstream pressure side and a downstream pressure side, the dynamic seal assembly including an annular seal member having a generally C-shaped cross-section and including opposed upstream and downstream legs defining an internal cavity with an opening facing toward the upstream pressure side of the valve, wherein the upstream leg has a radial length that is greater than a radial length of the downstream leg and includes a retaining foot that extends angularly away from the upstream leg in an upstream direction at an angle of between about 0 and 90, and a metallic spring is disposed within the internal cavity of the seal member for providing a constant sealing force to the seal member.