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.

There is provided a system separator having a backflow preventer including a housing enclosing a main flow conduit, a valve seat inside the housing on the main flow conduit, and a valve body movable relative to the valve seat to close off the main flow conduit together with the valve seat in a closed position and to release the main flow conduit in an open position. The valve body is alternately movable between the closed position and the open position by at least one of a pressure difference in the main flow conduit or a force of a spring element, and the main flow conduit is divided in the area of the valve body into at least one outer flow conduit and one inner flow conduit, and the valve body encloses the inner flow conduit and forms at least one valve-body valve seat on the inner flow conduit.

This invention is a new and novel embodiment of inflation valve for an inflatable boat or article, which also incorporates a separate and internal pressure release valve to allow the release of air when needed due to the rise of internal pressure inside said boat caused by temperature changes during the day, or any other over-pressure situation which could cause a rupture of the seams or outer shell.

A fluid control valve includes a housing body, a valve member, and a cap. The housing body includes a pipe part and a valve housing part. The valve housing part includes a valve opening, a pair of flat surfaces and an open end. In addition, the valve housing part houses the valve member configured to open and close the valve opening. The valve housing part has a central axis oriented perpendicular to a central axis of the pipe part. The cap closes the open end of the valve housing part. The flat surfaces are formed on opposite sides of a plane including the central axis of the valve housing part and the central axis of the pipe part. Each of the flat surfaces extend perpendicularly to the central axis of the valve housing.

An expansion tank includes a tank body mounted inside a housing forming a sump, and defining an internal expansion volume. A fluid inlet opening in the tank body is in communication with the sump and the expansion volume. A combination valve may be disposed on a lower end of the tank to control fluid flow between the sump and the expansion volume. The valve may be a combination duckbill valve and umbrella valve. Fluid enters the expansion volume through the umbrella valve when sump pressure exceeds expansion volume pressure by a first predetermined amount, and fluid exits the expansion volume through the duckbill valve to the sump when expansion volume pressure exceeds sump pressure by a second predetermined amount. The tank body may include a cover on which an inlet tube is formed.

A poppet-style check valve comprising a small poppet and a large poppet. When low flow rates are required, the small poppet opens and permits the low flow rate to pass efficiently. When demand for flow increases, the large poppet opens, permitting efficient passage of higher flow rates.

Ring disc nozzle check valve 100 allows fluid flow in one direction and can act as a relief valve and comprises valve body 1 which defines valve body fluid passageways 20,22 therethrough; primary seat 2 disposed in valve body fluid passageways 20,22 proximate fluid inlet 30; primary disc 4 disposed in valve body fluid passageways 20,22 proximate fluid inlet 30 and in communication with primary seat 2; secondary disc 5 nested within valve body fluid passageways 20,22, where secondary disc 5 defines secondary seat 3 at a peripheral edge of primary disc 4; diffuser 8 disposed in the valve body fluid passageway 20 proximate fluid outlets 32a,32b; primary spring 10 disposed in valve body fluid passageways 20,22 and in communication with diffuser 8 and primary disc 4, where primary spring 10 is adapted to urge primary disc 4 to a closed position; primary shaft 6 disposed within valve body fluid passageway 22 intermediate diffuser 8 and secondary disc 5, where primary shaft 6 is in communication with diffuser 8 and adapted to support and guide primary disc 4 and allow fluid flow through primary shaft 6; secondary shaft 7 disposed within valve body fluid passageway 22 and configured to support and guide secondary disc 5; secondary spring 11 disposed intermediate secondary shaft 7 and secondary disc 5 and configured to urge secondary disc 5 to a closed position; inner body valve seat support 9, which may act as a retention ring, disposed proximate to fluid outlets 32a,32b and configured to do not disrupt fluid flow within ring disc nozzle check valve 100 as the fluid passes over primary disc 4 and/or secondary disc 5; and one or more fasteners 12 configured to secure retention ring 9 to valve body 1.

This invention is a new and novel embodiment of inflation valve for an inflatable boat or article, which also incorporates a separate and internal pressure release valve to allow the release of air when needed due to the rise of internal pressure inside said boat caused by temperature changes during the day, or any other over-pressure situation which could cause a rupture of the seams or outer shell.

There is provided a system separator having a backflow preventer including a housing enclosing a main flow conduit, a valve seat inside the housing on the main flow conduit, and a valve body movable relative to the valve seat to close off the main flow conduit together with the valve seat in a closed position and to release the main flow conduit in an open position. The valve body is alternately movable between the closed position and the open position by at least one of a pressure difference in the main flow conduit or a force of a spring element, and the main flow conduit is divided in the area of the valve body into at least one outer flow conduit and one inner flow conduit, and the valve body encloses the inner flow conduit and forms at least one valve-body valve seat on the inner flow conduit.

A flapper assembly for an aspirator system includes a flapper plate and a valve assembly. The flapper plate defines a first plurality of apertures. The valve assembly includes a first valve plate disposed over the first plurality of apertures and a first pressure relief assembly arranged to move the first valve plate relative to the flapper plate.