A combined valve for insertion into an elongated bore of a power unit body of a hydraulic power unit may have an elongated carrier for receiving a relief and a check valve. The valve may also have a register arranged at a first axial position of a longitudinal axis of the carrier for calibration of the relief valve. The valve may also have a check valve coupled to the carrier at a second axial position along the longitudinal axis of the carrier. The valve may also have a relief valve coupled to the carrier at a third axial position along the longitudinal axis of the carrier. A minimal distance between the first and the second axial position may be less than a minimal distance between the first and the third axial position.

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 valve having at least one valve housing and at least one piston. The valve housing (7) has a hollow-cylindrical first portion (11) with a first diameter (D1) and a second portion (12), connected to the first portion (11), with a second diameter (D2); a first opening (15) is formed on the end face of the valve housing (7) and at least a second opening (16) is formed in the second portion (12); and the first diameter (D1) of the first portion (11) is greater than the second diameter (D2) of the second portion.

A valve having at least one valve housing and at least one piston. The valve housing (7) has a hollow-cylindrical first portion (11) with a first diameter (D1) and a second portion (12), connected to the first portion (11), with a second diameter (D2); a first opening (15) is formed on the end face of the valve housing (7) and at least a second opening (16) is formed in the second portion (12); and the first diameter (D1) of the first portion (11) is greater than the second diameter (D2) of the second portion.

A pressure regulator including a closure resisting mechanism that increases the total closure resisting force of a closure element to prevent the closure element from moving into a closed position until a predetermined pressure set point is reached. The closure resisting mechanism operates automatically and is spring actuated in response to pressure within a fluid pathway of the regulator. The closure resisting mechanism is disposed external to the fluid pathway so as not to impede fluid flow.

A relief valve has a valve body, a plunger assembly coupled to the valve body for selectively opening and closing the relief valve, and a support member secured to the valve body. A lockout lever is against the support member, forming a vertex. A spring rod is coupled to the lockout lever, and a spring is coupled to the spring rod, providing a bias force against the plunger assembly to normally close the relief valve. In a lockout position, the lockout lever is moved to pivot on the vertex against the support member to further compress the spring, which increases the bias force and, in turn, a cracking pressure of the relief valve.

The invention relates to a pressure maintaining gas cylinder valve. It consists of a pressure retaining device: The axis of the pressure retaining device and that of the valve element are in the same vertical plane; the pressure retaining device has a mounting base, a spring and a valve are located in the mounting base: the valve is in the valve element near the air outlet; the front section of the valve is near the air outlet, while the rear section of the valve is in the mounting base; the spring is between the valve and the mounting base. Because the invention has no eccentricity, the gas channel is smoother and the volume of the cylinder valve is greatly reduced. The mounting seat of the pressure retaining device not only provides support for the valve and spring, but also ensures that the stroke of the valve element is not interfered.

A pressure reducing valve includes: a body, a valve seat, and a valve element opening and closing the valve seat according to a difference between a pressure on the inlet side and a pressure on the outlet side. A pressure chamber, which is a space part between the valve element and the valve seat, is provided on the inlet side of the valve element. The valve element includes a plurality of horizontal holes each opening to the pressure chamber, and a vertical hole bringing the horizontal holes and the outlet side of the valve element into communication with each other. The horizontal holes and the vertical hole are provided in such a manner that a value of a ratio of a flow channel area of the vertical hole to a total area that is a total of flow channel areas of the horizontal holes exceeds 1.16.

The present disclosure provides a hydraulically controlled pressure relief valve without needing a hydraulic power unit. The valve maintains the accuracy of a hydraulically controlled valve by providing a self-contained closed hydraulic system built into the pressure relief valve. For safety, the valve can be kept open to call attention to the cause of the pressure relief valve activation, yet be easily reinstated into full service without replacing expendable components such as shear pins and rupture pins. The invention offers a pressure relief valve with accuracy, cost, and ease of use.

The present disclosure provides a hydraulically controlled pressure relief valve without needing a hydraulic power unit. The valve maintains the accuracy of a hydraulically controlled valve by providing a self-contained closed hydraulic system built into the pressure relief valve. For safety, the valve can be kept open to call attention to the cause of the pressure relief valve activation, yet be easily reinstated into full service without replacing expendable components such as shear pins and rupture pins. The invention offers a pressure relief valve with accuracy, cost, and ease of use.