A frequency-dependent damping valve arrangement of a vibration damper having a damping piston with at least one check valve, a control arrangement arranged coaxial to the damping piston including a control pot with a pot wall and a control piston axially displaceably arranged in the control pot that axially limits a control space. The control piston has a seal arrangement that seals the control piston relative to the pot wall including a circumferential groove formed at the control piston and a seal ring arranged therein. The seal arrangement is constructed such that this seal arrangement increases its sealing effect with rising damping medium pressure in the control space and reduces its sealing effect with falling damping medium pressure in the control space.

A frequency-dependent damping valve arrangement of a vibration damper having a damping piston with at least one check valve, a control arrangement arranged coaxial to the damping piston including a control pot with a pot wall and a control piston axially displaceably arranged in the control pot that axially limits a control space. The control piston has a seal arrangement that seals the control piston relative to the pot wall including a circumferential groove formed at the control piston and a seal ring arranged therein. The seal arrangement is constructed such that this seal arrangement increases its sealing effect with rising damping medium pressure in the control space and reduces its sealing effect with falling damping medium pressure in the control space.

The invention to a valve unit (1) for a synthetically commutated fluid working machine (51), comprising a valve body (19,57), a movably arranged valve unit (3) and a separate fluid flow influencing unit (13, 25, 31, 35, 46, 56). The fluid flow influencing unit (13, 25, 31, 35, 46, 56) comprises a fluid flow influencing means part (18) and an attachment means part (28, 34, 38) for mechanical connection with the valve body (19). The attachment means part (28, 34, 38) and the fluid flow influencing unit (18) are connected to each other by a connection means part (27, 30, 33, 40, 47). The circumferential extent of the attachment means part (28, 34, 38) is larger as compared to the circumferential extent of the connection means part (27, 30, 33, 40, 47).

The invention to a valve unit (1) for a synthetically commutated fluid working machine (51), comprising a valve body (19,57), a movably arranged valve unit (3) and a separate fluid flow influencing unit (13, 25, 31, 35, 46, 56). The fluid flow influencing unit (13, 25, 31, 35, 46, 56) comprises a fluid flow influencing means part (18) and an attachment means part (28, 34, 38) for mechanical connection with the valve body (19). The attachment means part (28, 34, 38) and the fluid flow influencing unit (18) are connected to each other by a connection means part (27, 30, 33, 40, 47). The circumferential extent of the attachment means part (28, 34, 38) is larger as compared to the circumferential extent of the connection means part (27, 30, 33, 40, 47).

The diaphragm valve shown in my U.S. Pat. No. 6,615,774 is modified to improve performance by providing multiple overlapping springs to provide increased spring life and different stages of resistance on the diaphragm, a multi-arm housing having holes and tapered edges in each arm to increase air flow, a self seating seal in the housing which contacts the diaphragm, and a diaphragm guide surrounding the guide shaft having lands and spaces about the shaft in capture lubrication and vibration dampening holes surrounding the lands and spaces.

The diaphragm valve shown in my U.S. Pat. No. 6,615,774 is modified to improve performance by providing multiple overlapping springs to provide increased spring life and different stages of resistance on the diaphragm, a multi-arm housing having holes and tapered edges in each arm to increase air flow, a self seating seal in the housing which contacts the diaphragm, and a diaphragm guide surrounding the guide shaft having lands and spaces about the shaft in capture lubrication and vibration dampening holes surrounding the lands and spaces.

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 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 valve structure includes: a valve unit including a valve body, a shaft portion extending from the valve body, and a separating portion provided on the shaft portion and spaced apart from the valve body; a mounting plate located between the valve body and the separating portion and including an insertion hole into which the shaft portion is inserted; a holding portion including a first holding surface provided on the mounting plate, and a second holding surface provided on the valve unit and spaced apart from the first holding surface; a protrusion provided on one of the valve unit and the mounting plate, an end of the protrusion protruding beyond the first and second holding surfaces; and an elastic body including a contact portion located between the first and second holding surfaces, and a pressed portion located inside or outside the contact portion and contacting the protrusion.

A valve assembly adapted for use in oil and gas operations. In one aspect, the valve assembly includes a valve body defining an internal region, an inlet passageway, and an outlet passageway, the inlet and outlet passageways extending into the internal region; a valve seat connected to the valve body and defining a fluid passageway; a clapper extending within the internal region and defining an annular groove; and a seal extending within the annular groove of the clapper and adapted to sealingly engage the valve seat. In an example embodiment, the clapper is actuable between an open configuration, in which fluid flow is permitted through the fluid passageway; and a closed configuration, in which the seal sealingly engages the valve seat to at least partially restrict fluid flow through the fluid passageway.