An eccentric butterfly valve that maintains high sealability when closed even when a high-pressure fluid is oriented in either direction of a forward flow or backflow. The valve includes a disk (23) axially supported at an eccentric position via a stem (22) inside a body (21). The disk is provided to a seat ring (24) fixed with a seat retainer (25) so as to be hermetically sealable. A flexible part is formed on an inner diameter side of the seat ring, and a spring member is mounted between the flexible part and the seat retainer. In the spring member, a load increases substantially in proportion to the magnitude of tilt of the flexible part when the disk is displaced to a seat retainer side. When the flexible part is elastically deformed, the spring member is elastically deformed in a state where contact with the seat retainer is avoided.

Valve comprising a body (2), a centred butterfly (1), mounted with the ability to rotate inside the body (2) from an open position revealing the passage to a closed position covering said passage, and a seal (3) arranged inside a housing which is delimited by the seat and by a face, opposite the seat in the closed position, of the butterfly, the seat and the face converging towards the inside in the axial direction. The seal (3) moves freely in the housing.

A vacuum pressure control apparatus includes an annular elastic seal member formed with a valve seat, and a doubly eccentric butterfly valve element configured to come into contact or separate from the valve seat. The vacuum pressure control apparatus is to be placed on a pipe connecting a vacuum chamber and a vacuum pump. The vacuum pressure control apparatus is configured to rotate the butterfly valve element in a first direction from a first valve closed position corresponding to an initial state to change vacuum pressure in the vacuum chamber. The vacuum pressure control apparatus further includes a control unit configured to rotate the butterfly valve element in a direction opposite to a first direction so that the butterfly valve element is moved to a second valve closed position different from the first valve closed position.

A valve device for a motor vehicle, comprising a housing, a flow channel located in the housing, a flap arranged in the flow channel for closing the flow channel, the flap having regions in which a pin penetrating the flap is fastened and the pin is rotatably mounted in the housing, and a valve seat, which is arranged in the flow channel and which is in contact with the flap when the latter is in the closed position. The seal is arranged in the flow channel, the side of the seal facing the flap having a wall thickness which is greater than the rest of the cross-sectional surface, the area being opposite the flap in the closed state.

A butterfly valve seal arrangement in a butterfly valve having a cylindrical flow channel with a wall includes a seal flange, an elastomeric seal, a seal channel, and an annular seal retaining ring. The seal flange extends into the cylindrical flow channel from the wall of the cylindrical flow channel. The seal channel is recessed into the wall of the cylindrical flow channel adjacent to the seal flange. And the annular seal retaining ring includes tabs extending into the seal channel which hold the annular seal retaining ring in the cylindrical flow channel. An elastomeric seal is held in compression in the seal channel and against the seal flange by the annular seal retaining ring, and extends into the cylindrical flow channel forming a seal surface held in compression against a vane seat of a vane in a position perpendicular to a direction of flow.

Flap valves include a valve housing and a flap disc in a flow channel of the valve housing. The flap disc can be pivoted between an open position and a closed position. The flow channel on its outer circumference includes a sealing lip arrangement, which has two elastic sealing lips arranged at a distance from each other in the direction of flow. With the valve disc in the closed position, the sealing lips bear under elastic prestress against the sealing surface of the valve disc to form a seal and thereby form an annular cavity surrounding the sealing surface of the valve disc. Further, with the flap disc in the closed position, the passage of fluid from the high-pressure side in the flow channel to the low-pressure side of the flow channel prevented due to the cross-sectional areas of the two sealing lips of the sealing lip arrangement being inclined or bent towards the inside of the annular cavity.

Technologies are described for diaphragm valves with plastic diaphragm and reduced or no elastomer backing cushion, where peripheral or all sealing forces may be applied directly to the diaphragm of the valve assembly. In various examples, the valve assemblies may include a pressure ring to apply sealing force to a surface of the diaphragm with a reduced size or no backing cushion allowing a two-fold or more increase in pressure capacity of the valve assembly. In other examples, an elastomer or metallic spring placed above a center diaphragm boss may provide center-to-edge compliance for passage seal.

The disclosure relates to a butterfly valve having a valve opening defined through the valve body and including a seat retainer fastened to the valve body; a disc with an optimized profile rotatably mounted within the valve opening; an interstice between the disc and valve body; a valve seat cavity defined in the seat retainer and the valve body; a fluid port defined in the valve body, wherein the fluid port is connected to the valve seat cavity and the interstice.

An eccentric butterfly valve that maintains high sealability when closed even when a high-pressure fluid is oriented in either direction of a forward flow or backflow. The valve includes a disk (23) axially supported at an eccentric position via a stem (22) inside a body (21). The disk is provided to a seat ring (24) fixed with a seat retainer (25) so as to be hermetically sealable. A flexible part is formed on an inner diameter side of the seat ring, and a spring member is mounted between the flexible part and the seat retainer. In the spring member, a load increases substantially in proportion to the magnitude of tilt of the flexible part when the disk is displaced to a seat retainer side. When the flexible part is elastically deformed, the spring member is elastically deformed in a state where contact with the seat retainer is avoided.

A frictionless rotary valve comprising: a valve body to be connected within a gas meter, the valve body comprising: a seal, fixedly attached near an outlet of the valve body; and a valve disc, having a ball bearing attached to the valve body; and a gear mechanism comprising: a worm wheel engaged with a worm, wherein the worm wheel is attached to a second end of the valve disc; a drive gear connected to the worm, wherein a rotation of the drive gear in a clockwise direction rotates the worm wheel in an anti-clockwise and moves the valve disc in a closed position; a worm wheel stop, for restricting a movement of the worm wheel in the anti-clockwise direction and driving the worm wheel in a vertically upward direction; and a linear guide attached to the worm wheel.