A valve device includes a valve seat, a valve body, a buffer, and a non-overlapping portion. The valve seat has an opening that communicates with an exhaust flow path. The valve body is configured to open and close at least a part of the opening. The buffer is disposed between the valve seat and the valve body and is more flexible than the valve seat. The non-overlapping portion is configured so that the valve seat and the valve body do not overlap each other in an opening and closing direction of the valve body at at least a part of an outer periphery of the valve body in a state where the valve body is closed.

A method of controlling the discharge of waste water from a toilet includes the installation of a valve in the discharge outlet of the toilet, the valve including a valve body and a spring-loaded valve closure member that is movable relative to the valve body into an open position during flushing of the toilet against the action of its spring-loading and which is returned to the closed position by the action of its spring-loading on completion of the flushing operation.

A fluid flow control unit, in a preferred embodiment, mounted on a section of pipe having a tubular wall forming a fluid flow passage with a flow axis, the unit having a gate section, and a gate pivot section, the pivot section having a body portion mounted on the pipe outer wall surface, a gate mounting cavity formed in the body portion and opening through the pipe wall and providing an access port for the gate section to the mounting cavity, a pivot shaft positioned in the cavity and mounted on bearing structure on the body portion, the diameter of the shaft being dimensioned to allow a laterally curved gate which is affixed to a surface portion of the shaft to pivot up against a ceiling of the pipe to thereby be out of the flow passage main stream at a full open, non-blocking position of the gate, and a gate position control structure on the unit for allowing predetermined degrees of rotation of the pivot shaft in response to the magnitude of fluid flow pressure forces directed against the gate.

Provided is a muffler valve 1 that opens and closes an exhaust passage according to a pressure of an exhaust gas of an engine. A valve body 3 is swingably supported by a support shaft 4 with respect to a valve seat 2 having an opening 22, the valve body 3 is urged in a closing direction by a coil spring 5 externally inserted on the support shaft 4, a valve seat hook portion 23 is provided so as to embrace both ends of the support shaft 4 in a circumferential direction and is fixed to the support shaft 4, and a valve body winding portion 34 is provided so as to embrace the coil spring 5 in the circumferential direction from a direction opposite to the valve seat hook portion 23 and embrace the coil spring 5 over an entire length of the coil spring 5 in the circumferential direction. It is possible to prevent or suppress axial misalignment of the coil spring coaxially externally inserted on the support shaft for opening and closing the valve body as much as possible, and appropriately control the opening and closing of the valve body with high stability.

A valve for controlling a gas stream between a first side and a second side of the valve is described. A valve opening is passage for the gas stream between the first side and the second side. A valve closure with a valve plate closes the valve opening. A valve mount is arranged toward the second side and on which the valve closure is mounted. The valve closure is pretensioned in the direction of the first side to close the valve toward the second side by the valve plate. The valve plate has an opening element which can be opened toward the first side in the event of an overpressure on the second side.

A valve device is configured to adjust an opening degree of a flow path for fluid, and includes an axial member, a valve body, and a biasing member. The axial member is configured to be fixed to the flow path. The valve body is rotatable about the axial member, and is configured to be rotated in a closing direction in which the opening degree is reduced, and to be rotated, by the use of a fluid flowing down through the flow path, in an opening direction in which the opening degree is increased. The biasing member is provided to the axial member inside the flow path, and is configured to bias the valve body to rotate in the closing direction.

A valve assembly with a spring retention assembly including an elongated cylinder portion having an open threaded end and a closed end and an elongated piston portion having a free end and a threaded tab end configured to thread through the open threaded end and, thereby, be slideably captured in the cylinder portion. A spring couples to the body portion and the piston portion to provide a force to urge the body portion and the piston away from one another, wherein the closed end and the free end are similarly shaped so that the spring retention assembly can be reversibly mounted to a valve member that can also be reversibly mounted.

A flapper and seat assembly, and systems and methods utilizing such assembly, are disclosed. The flapper and seat assembly includes a tubular metallic seat having a bore therethrough. The tubular metallic seat is one solid unit. The flapper and seat assembly further includes a hinge coupled to the tubular metallic seat and a flapper. The flapper is pivotally mounted to the hinge such that it is rotatable between an open position and a closed position. The flapper and seat assembly also includes a secondary sealing element located between the flapper and the tubular metallic seat. The secondary sealing element is one of an undulating or curved lip seal. The flapper and seat assembly further includes a seal that is formed between a sealing surface of the flapper and a sealing surface of the tubular metallic seat. The seal comprises an angle measured from a plane perpendicular to the centerline of the flapper and seat assembly.

A check valve can include a valve body defining a valve bore, the valve body comprising an annular body and a cross member secured to and extending in a radial direction across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a pair of valve members, each valve member of the pair of valve members positioned within the valve body and configured to rotate between open and closed positions; and a pivot pin positioned within the valve body and extending through the position block and each valve member of the pair of valve members, the pivot pin being supported only by the position block.

A valve device includes a rotation shaft, a valve body, and a biasing portion. The valve body is configured to be rotationally displaceable about the rotation shaft between a closed position and an open position. The biasing portion biases the valve body so as to cause the valve body to approach the closed position. The valve body includes an upstream wall arranged in a position upstream of the rotation shaft in a flow direction of the fluid when the valve body is in the closed position. The valve body includes a rotation end, which is an end distal from the rotation shaft and moves downstream in the flow direction of the fluid in response to a displacement of the valve body from the closed position to the open position, and the rotation end is shaped to project upstream when the valve body is in the closed position.