According to the present disclosure, there is provided a check valve comprising a valve housing defining a pair of valve openings. A pair of flapper elements are pivotably mounted to at least one hinge pin for rotation relative to the housing between an open position in which they permit fluid flow through the respective valve openings and a closed position in which they prevent fluid flow through the valve openings. The check valve also includes at least one hinge pin receiving post that extends upwardly from the valve housing, wherein the at least one hinge pin receiving post comprises a first, lower end portion having an opening for receiving said at least one hinge pin, a second, upper end portion and a flexible, serpentine portion intermediate said end portions.

A flow control device includes a housing having a primary inlet, a secondary inlet, and an outlet disposed downstream of the primary and secondary inlets. The flow control device further includes a chamber defined by an inner circumferential surface of the housing. The chamber fluidly connects the primary and secondary inlets with the outlet. A valve member is mounted in the chamber to pivot toward and block the primary inlet by fluid pressure in the secondary inlet when fluid pressure into the secondary inlet is higher than fluid pressure into the primary inlet.

An automatic shutoff valve for breakaway wet barrel fire hydrant is disclosed. In general, one aspect disclosed features an apparatus comprising: a valve housing comprising a valve body, a flange, and a valve seat; a valve pedal configured to engage the valve seat and prevent fluid flow through the valve seat in a closed position, and to permit fluid flow through the valve seat in an open position; a lockout tab disposed within the valve body, wherein the lockout tab maintains the valve pedal in the open position; a lockout bar disposed distally from the valve body; and an activation rod mechanically coupled to the lockout bar and configured to keep the valve pedal engaged with the lockout tab.

A check valve includes a housing, a flap, a hinge, at least one post, and at least one tubular bumper. The hinge allows the flap to rotate relative to the housing between a fully open position and a closed position. The at least one post is disposed at or near the periphery of the housing supporting the hinge and extending axially relative to the housing from the housing. The at least one tubular bumper is movable with the flap and configured to contact the at least one post when the flap pivots to the fully open position.

A check valve comprises a valve housing defining a valve opening, a pair of mounting posts arranged on opposed sides of the valve opening and a hinge pin mounted between the mounting posts. A pair of flapper elements are pivotably mounted to the hinge pin for rotation relative to the housing between an open position in which they permit fluid flow through the valve opening and a closed position in which they prevent fluid flow through the valve opening. The valve further comprises a stop mounted between the mounting posts above the hinge pin and extending across the valve opening such that the flapper elements will contact the stop in their open positions. The stop is a coil spring.

A check valve comprises a valve housing defining a pair of valve openings, a pair of flappers pivotably mounted for rotation relative to the housing between an open position in which they permit fluid flow through the respective valve openings and a closed position in which they prevent fluid flow through the valve openings, and a stop pin extending across the valve such that the flappers will contact the stop pin in their open positions. Each flapper comprises a primary flapper element and a secondary flapper element, each pivotally mounted to a hinge pin extending across the valve. The primary flapper element further comprises a flapper opening formed therethrough. The secondary flapper element is pivotally mounted to the hinge pin such that it may rotate relative to the primary flapper element for opening or closing the flapper opening.

A check valve comprises a valve housing defining a valve opening and a web extending across the valve opening. First and second mounting posts are provided on the valve housing on opposite sides of the opening and extend away from the opening. Each mounting post has a transverse bore formed therein.

A check valve comprises a valve housing defining a valve opening and a pair of flapper elements pivotably mounted relative to the housing for rotation between an open position in which they permit fluid flow through the opening and a closed position in which they prevent fluid flow through the opening. Each flapper element comprises a first surface facing the opening and a second surface opposite the first surface and facing away from the opening. The valve further comprises a bowed leaf spring member mounted to the second surface of each flapper element. The leaf spring members are arranged such that when the flapper elements move towards the closed position, the bowed leaf spring members move into engagement with one another.

A flow control device includes a housing including a primary inlet and a secondary inlet each disposed on an upper surface of the housing, and an outlet disposed on a lower surface of the housing gravitationally downstream of the primary and secondary inlets. A chamber is disposed within the housing and fluidly connects the primary and secondary inlets with the outlet. A valve member is pivotally mounted on an upper surface of the chamber, the valve member configured to pivot in response to higher fluid pressure from gravitational fluid flow through one of the primary inlet and the secondary inlet.

A gas flow adjusting device is provided, which includes a tube body, a first horizontal shaft, a second horizontal shaft, two leaf structures, a torsional spring and two linkage assemblies. The first and second horizontal shafts are disposed in an accommodating space of the tube body and spaced apart from each other along an axial direction of the tube body. The leaf structures are pivoted on the first horizontal shaft and have a swinging direction identical to the axial direction. The torsional spring is sleeved around the second horizontal shaft and provides a resilient force along the axial direction. The linkage assemblies are connected to the leaf structures respectively, and each of the linkage assemblies is connected to the second horizontal shaft and the torsional spring. Therefore, when the leaf structures swing to different angles, the twisting amounts of the torsional spring are minimally varied.