An improved deflator valve is described herein. The deflator valve has a main body with one or more ports, one or more vents, or port or vent slots for introducing air into or relieving pressure from within the main body in a vortex, circular flow. The deflator valve also includes a piston having an O-ring disposed around an outer circumference of the piston. The O-ring of the piston and the ports and vents are effective for reducing noise and deflation time and improving accuracy and ease of adjusting a pressure setting. The deflator valve can further include a dual or variable rate spring that can achieve an extensive destination pressure range. The deflator valve can also include a threadless lead in, fewer valve stem threads, or a lock chuck for enhanced valve stem attachment methods.

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 relief valve includes: a housing having a hollow cylindrical valve chamber and having a first communication port opening on one end side of the valve chamber; a first valve element for opening and closing the first communication port; a first spring for biasing the first valve element in the closing direction; and a retainer having a spring seat for supporting the first spring. A set load of the first spring is adjusted based on the press-fit amount of the retainer with respect to the housing. A press-fit piece member including a plurality of press-fit pieces is formed in the retainer, such that the press-fit pieces of the press-fit member are arranged to be spaced away from each other in the circumferential direction of the retainer and elastically abut the housing.

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 backflow prevention device includes a piston received in a device passage between an inlet port and outlet port. A relief port can fluidly communicate with a middle segment of the device passage. The piston is movable between a normal flow position in which the piston blocks fluid communication between the relief port and the middle segment of the device passage and a backflow position in which the piston allows fluid communication between the relief port and the middle segment of the device passage. The piston can move to the normal position in response to normal flow through the device passage from the inlet port toward the outlet port and configured to move to the backflow position in response to greater pressure in the middle segment than in the inlet port.

A non-return valve with twin plugs is connected to a fluid reservoir and equipment that can receive a small overflow quantity essentially in the gaseous state from the reservoir. This occurs when the primary valve is open. In the case of a larger overflow essentially in the liquid state, the openings are switched over to evacuate the overflow to another outlet branch of the non-return valve, without it being transferred to the equipment. The invention is useful in an oil lubrication circuit, in which a hypothetical fuel leak into the oil could cause the oil reservoir to overflow into the non-return valve and in which a significant flow of liquid to the equipment must be avoided; oil outlet through the other branch of the outlet can remain in a reservoir provided with a drain system.

An improved deflator valve is described herein. The deflator valve has a main body with one or more ports, one or more vents, or port or vent slots for introducing air into or relieving pressure from within the main body in a vortex, circular flow. The deflator valve also includes a piston having an O-ring disposed around an outer circumference of the piston. The O-ring of the piston and the ports and vents are effective for reducing noise and deflation time and improving accuracy and ease of adjusting a pressure setting. The deflator valve can further include a dual or variable rate spring that can achieve an extensive destination pressure range. The deflator valve can also include a threadless lead in, fewer valve stem threads, or a lock chuck for enhanced valve stem attachment methods.

A pressure valve includes a housing having bottom portion defining a bottom opening configured to be in communication with a vessel and a sidewall defining an internal cavity. The housing includes a vent aperture configured to provide fluid communication between the internal cavity and ambient air surrounding the pressure valve and an accessory aperture configured to couple an accessory to the housing. A seal seat is positioned within the internal cavity fluidly between the vent aperture and the bottom opening. A pressure control assembly is coupled to the housing. The pressure control assembly breaks a sealing engagement with the seal seat to provide fluid communication between the vessel and the vent aperture in response to a desired positive pressure being reached within the vessel or in response to a negative pressure being reached in the vessel. The accessory aperture is positioned between the bottom opening and the seal seat.

A pressure regulating valve comprises a valve housing comprising a pressure-regulating chamber having an inlet for high pressure fluid and an outlet for pressure-regulated fluid, and a valve element received in the pressure-regulating chamber and movable axially therein for regulating the pressure of the fluid passing from the inlet to the outlet. The valve element comprises a regulating element having a regulator head slidably and sealingly received in the valve housing, the regulating element extending into the regulating chamber, at least one spring, and an adjustment head for adjusting an initial compression of the at least one spring within the regulating chamber. The at least one spring is integrally formed with and extends between the regulator head and the adjustment head.

A pressure relief valve (10) is provided for controlling fluid flow between a first fluid path (12a) and a second fluid path (12b). The pressure relief valve includes a housing (14), a diaphragm member (24) movably affixed within the housing and having a fluid port (18), a first biasing member (20) for urging the diaphragm member in a first direction, and a sealing member (26) movably mounted in the housing and configured for reversibly sealing the fluid port (18). When a pressure at the second fluid path (12b) exceeds a first predetermined threshold the diaphragm member (24) is pushed against the first biasing member (20), and the sealing member (26) is initially urged towards the fluid port (18) and subsequently becomes disengaged with the fluid port, allowing fluid communication between the second fluid path (12b) and the first fluid path (12a) via the fluid port. When the pressure at the second fluid path (12b) decreases below a second predetermined threshold, the sealing member (26) becomes disengaged from the diaphragm member (24), allowing fluid communication between the first fluid path and the second fluid path via the fluid port. A valve assembly including the pressure release valve (10) and an externally actuated valve (60) is also provided.