An offset butterfly valve comprising a butterfly disc which receives a splined valve stem is disclosed. The butterfly disc is positioned for sealing an annulus formed in the valve housing when the valve stem is rotated from an open position to closed position. Provision of the spline towards the center of the valve stem and the butterfly disc allows the butterfly disc to move along the valve stem. In a particular embodiment a valve seal is secured to the butterfly disc using a securing disc which is threaded into a threaded cylinder concentric with the butterfly disc.

[Problem] To provide a centric butterfly valve which has favorable sealability around stems and small open/close operation torque and is also excellent in durability. [Solution] A centric butterfly valve (1) in which top and bottom boss surfaces (19, 29) are formed to be spherical, an outer peripheral end of the blade portion of the valve disk (24) is formed to be an M-shaped section part (29) with round-shaped apex parts (27) and a round-shaped valley part (28) smoothly linked, and the centric butterfly valve has a valve disk (3) having an extended part (41) obtained by successively and slightly extending the spherical surface of each of the top and bottom boss surfaces (19, 20) to a blade portion (40) side.

A damper assembly for use in a round forced air duct feeding a register vent through a register boot includes a damper frame having a frame periphery with a first side and a second side that is at least substantially parallel with the first side, the first side and the second side each having a length that is greater than a distance between the first side and the second side. A damper blade is pivotable relative to the damper frame about an axis of rotation, at least substantially parallel with the first side and the second side, between an open position and a closed position. A flexible outer seal extends outwardly from the frame periphery of the damper frame and is at least substantially circular in order to seal against an inner surface of the round forced air duct.

The main purpose of the invention is a metal sealing system (6) for a triple eccentricity butterfly valve (30) comprising: a dynamic metal seal (21), comprising a metal core surrounded by an external coating; a metal case (15) with an external surface that has an inclined conical shape, comprising a first housing inside which the dynamic metal seal (21) is mounted; a metal cover (29) fixed to the metal case (15) to allow it to close by flush fitting of the upper or lower faces of the metal cover (29) and the metal case (15), the metal case comprising a second housing into which the metal cover fits, the dynamic metal seal (21) being located between the metal cover (29) and the surface of the metal case (15) defining the first housing.

Example seal glands for butterfly valves are disclosed herein. An example butterfly valve disclosed herein includes a valve body and a valve retainer mounted to the valve body, where the valve body and the valve retainer define a circumferential cavity. The example circumferential cavity includes a first surface substantially perpendicular to a longitudinal axis of a flow path of process fluid through the butterfly valve, a second surface substantially perpendicular to the longitudinal axis, where the second surface offset from the first surface, and a third surface extending between the first surface and the second surface. In the example butterfly valve, the first surface, the second surface, and the third surface enable a seal to translate within the cavity in a direction substantially parallel to the first surface.

A valve assembly has a stationary valve body and a valve member that is movable relative to the valve body at least from a closed position, in which the valve member cooperates with a valve seat to completely obstruct a fluid path formed through the valve body, to an open position, which allows fluid to flow through the fluid path. The valve member has a disc- or ball-shaped rigid component that is overmolded with a flexible component and at least partially encompasses the rigid component in a circumferential direction to form a ring gasket section.

A fluid switchover device includes a housing having at least three ports leading into an interior space; a valve flap rotatably arranged within the housing and having a rotational axis that is mounted to the housing at first and second locations; and a circumferential seal mounted to the valve flap and having first and second evasion portions at first and second locations, respectively, which are configured to evade the rotational axis on the same side of the valve flap, and the valve flap is configured to slidingly engage a boundary of the interior space by means of the circumferential seal, so that at a first position of the valve flap, the first and second ports are connected, and the first and third ports are mutually sealed off, and in a second position, the first and third ports are connected, and the first and second ports are mutually sealed off.

A valve comprising a valve body including a first end and a second end spaced apart along a longitudinal axis, a central portion disposed between the first end and the second end, wherein the first end and the second end define a first flow passageway and a second flow passageway, respectively, and wherein the central portion defines an interior chamber, wherein the first end of the valve body includes a bore, a valve seat disposed in the bore including a concave seating surface, and a disc rotatable within the interior chamber between an open position and a closed position, wherein the disc includes a seal having a shape corresponding to the concave seating surface and wherein the shape of the seal and the concave seating surface define an elliptical offset from a centerline of the valve.

A valve body has a substantially disk shape and is provided in a gas passage. A shaft supports the valve body so as to be rotatable in the gas passage. A groove portion is provided at an outer edge portion of the valve body on an outer side in a radial direction so as to extend in a circumferential direction of the valve body. A seal ring is formed in an annular shape, has a separated portion as a cut in a part in the circumferential direction, and is fitted in the groove portion of the valve body. At least one of one end surface in a circumferential direction and the other end surface in the circumferential direction of the seal ring is a inclined surface that is inclined so as to guide a foreign matter accumulated in a gap of the separated portion to an outside of the gap.

A valve comprising a valve body including a first end and a second end spaced apart along a longitudinal axis, a central portion disposed between the first end and the second end, wherein the first end and the second end define a first flow passageway and a second flow passageway, respectively, and wherein the central portion defines an interior chamber, wherein the first end of the valve body includes a bore, a valve seat disposed in the bore including a concave seating surface, and a disc rotatable within the interior chamber between an open position and a closed position, wherein the disc includes a seal having a shape corresponding to the concave seating surface and wherein the shape of the seal and the concave seating surface define an elliptical offset from a centerline of the valve.