A check valve including a clevis, a hinge pin, a hinge configured to be rotatably coupled to the clevis by the hinge pin, and a disc configured to be detachably coupled to the hinge. The hinge includes a first hinge member having a male interlocking feature and a second hinge member defining a female interlocking feature corresponding to the male interlocking feature. The second hinge member is configured to be detachably coupled to the first hinge member. When the first hinge member is coupled to the second hinge member, the male interlocking feature of the first hinge member is received in the female interlocking feature defined in the second hinge member to prevent angular separation of the first and second hinge members about the hinge pin. The first and second hinge members may define a non-circular opening configured to prevent rotation of the disc relative to the hinge.

The present disclosure provides a method and apparatus for draining. The apparatus includes a body, the body having a first compartment adjacent to a second compartment, the first compartment having an inlet port fluidly connected to an outlet port, the inlet port defining a needle seat within the first compartment, a first rod hole for operation with a second rod hole in the second compartment, and a plurality of venting holes, the second compartment having a plurality of spaced notches along. The apparatus further includes a setting rod, the setting rod having a shaft and a sealing head, the shaft sized to be slideably maintained in the first rod hole and the second rod hole, the sealing head slideably attached to an end of the shaft and sized to obstruct fluid flow from the inlet port at the needle seat.

A valve assembly includes a valve body with a central passage, an upstream end for receiving a fluid, and a downstream end for discharging the fluid. A segment ball valve rotates between a valve open position to allow the fluid to flow through the central passage, and a valve closed position to prevent the fluid from flowing through the central passage. A check valve located within the central passage downstream from the segment ball valve is biased to prevent the fluid from traveling upstream through the central passage, and to allow the fluid to travel downstream past the check valve. A locking mechanism secures the check valve in a locked position to prevent the fluid from flowing past the check valve. A sealable cavity is located between the segment ball valve and the check valve, to contain a neutral media to achieve a double block and bleed feature.

A valve assembly includes a valve body with a central passage, an upstream end for receiving a fluid, and a downstream end for discharging the fluid. A segment ball valve rotates between a valve open position to allow the fluid to flow through the central passage, and a valve closed position to prevent the fluid from flowing through the central passage. A check valve located within the central passage downstream from the segment ball valve is biased to prevent the fluid from traveling upstream through the central passage, and to allow the fluid to travel downstream past the check valve. A locking mechanism secures the check valve in a locked position to prevent the fluid from flowing past the check valve. A sealable cavity is located between the segment ball valve and the check valve, to contain a neutral media to achieve a double block and bleed feature.

A gas heater includes a premix burner, a supply channel for supplying a mixture of a gaseous fuel and air to the burner, and a check valve placed in the supply channel upstream of the burner. The check valve includes a moveable valve body having a first end position in which the check valve is opened and a second end position in which the check valve is closed. In a first pressure condition in which a pressure upstream is higher than a pressure downstream, the valve body is urged to the first end position. In a second pressure condition in which the pressure upstream is lower than the pressure downstream the valve body is urged to the second end position. After closure of the check valve the check valve remains closed for a delay time.

Embodiments of air admittance valve assembly and plumbing system incorporating the same are provided herein. In some embodiments, a valve assembly to allow or stop a flow for use with enclosed environment includes a housing having, an inlet disposed at a first end of the housing fluidly coupled to environment surrounding housing, an outlet disposed at a second end of housing fluidly coupled to enclosed environment, and an interior volume divided into a first zone, a second zone, and a third zone; a first valve having a first valve seat and a first sealing member urged by an existing force between a closed or open position; and a second valve having a second valve seat and a second sealing member urged by an existing force between a closed or open position.

A hydrostatic axial piston machine includes a double-acting actuating cylinder configured to adjust the piston displacement. The actuating cylinder has two actuating chambers that are connected to two spatially separated cartridge valves. The two cartridge valves are inserted obliquely into a wall section of the axial piston machine. The wall section on the one hand forms a wall of the housing of the axial piston machine and on the other hand forms a wall of the actuating cylinder.

The systems and methods of the present disclosure provides an independent passive variable resistor that can be interposed between a fluid reservoir at an inlet pressure and receptacle at an outlet pressure. The resistor can adjust resistance to the pressure difference from the input to the output so that the flow rate through it is a constant rate. The resistor can include a moveable element and a biasing mechanism located in a chamber to create a flow channel. Each side of the moveable element is exposed to the inlet and outlet pressures and moves within the flow channel to modify the resistance of the flow through the chamber in response to the pressures. The balance of these forces determines the position moveable element, which interacts with the fluid channel to determine the flow resistance through variable resistor. The biasing mechanism can provide the necessary pressure to establish equilibrium flow rate.

A spring-driven guided check valve which eliminates fluttering of the disc as it moves between the open and closed position against a seat. A disc has an integrated guide which slides against a sleeve inside the body of the valve. This configuration only allows linear movement of the seat in a direction towards (and away) from an inlet face without changing the orientation of the disc. The disc is held in a constant orientation and thus cannot shift at an inclined attitude (flutter). Thus, once the valve closes and the disc makes contact with the seat, the entire disc would contact the entire seat at the same point in time because of the parallel orientation of the disc to the contacting surface of the seat.

A valve device includes: a poppet that is formed in a hollow shaft shape except for a leading end, has a tapered closure part at the leading end and a side hole passing through a wall of the hollow shaft-shaped part, and rotates around a shaft center thereof during opening and closing actions; and a valve seat having a sloped seat surface with which the closure part of the poppet comes into contact when closing the valve device. The closure part of the poppet or the seat surface of the valve seat, whichever has a higher hardness, has a cut mark of the opposite direction from a direction of rotation of the poppet around the shaft center that occurs during the valve closing action.