The butterfly valve comprises a body in which an inserting space is formed; and a disk inserted into the inserting space of the body, wherein fluid flow is opened or closed in response to rotation of the disk, wherein the disk further includes: a disk body formed of a metal; a first plastic layer formed of a first plastic on the disk body; a second plastic layer formed of a second plastic on the first plastic layer, wherein a melting point of the first plastic layer is different from a melting point of the second plastic layer, and the disk body is formed of a framework structure having an internal space.

A butterfly valve includes a drive unit and a valve unit that are coupled to each other. The drive unit includes a hollow part in which a rod is inserted between a DD motor and an end portion of the drive unit on a coupling side to the valve unit. In the hollow part, a cylindrical magnetic member is placed coaxially with the rod to cover the outer peripheral surface of the rod. A magnetic fluid is filled in a void between the outer peripheral surface of the magnetic member and the inner peripheral surface of the hollow part. The rod is made of a non-magnetic corrosion-resistant alloy.

An improved butterfly valve having (a) a valve housing, (b) a valve-plate having a peripheral edge located in a central plane when in a fully-closed position, (c) a valve stem configured to rotate the valve-plate about an axis parallel to the central plane to control flow through the valve, and (d) a valve seat configured to engage the peripheral edge to form a seal when the valve-plate is in closed positions, the improvement wherein the valve seat comprises (1) a resilient sealing member having an inward valve-seating surface engaging the peripheral edge therearound and an opposite outward surface; and (2) a ring structure: (i) having an inner surface adjacent to the outward surface; (ii) having the valve stem passing therethrough along the axis; (iii) divided into two sub-ring portions adjacent to each other with valve-stem-adjacent ends; and (iv) sized to permit central-plane-parallel relative sub-ring-portion displacement perpendicular to the axis, thereby lowering valve actuation force.

A fluoroplastic butterfly valve structure is disclosed that includes an inner metallic butterfly disc and an outer fluoroplastic material enclosing the metallic butterfly disc within a valve body. The butterfly disc has a board-like or cone-like cross section. A fluoroplastic lining has an interference fit with the butterfly disc. A back-up ring is provided between an inner surface of the valve body made of high temperature resistant rubber. The butterfly disc has a complex sealing structure, which includes an unequal-width conical surface and an unequal-width curved surface. The unequal-width curved surface is disposed in a closing direction of the butterfly disc for preventing interference sliding thereof.

A valve includes an actuation assembly including a drive device that generates a driving force, a needle shaft connected, at one end thereof, to the drive device to receive the driving force from the drive device and perform linear motion, a needle nut that is coupled to the drive device and that has an empty space through which the needle shaft passes, so as to guide the linear motion of the needle shaft, and a valve disc coupled to an opposite end of the needle shaft, a body is coupled with the actuation assembly and that has a valve opening inside, the valve opening being selectively opened or closed as the valve disc, which is inserted into the body in which water flows, performs linear motion, and a clip that fixes the body and the actuation assembly such that the body and the actuation assembly are not separated from each other.

Disclosed is a valve comprising: an annular body defining a body bore having a bore axis, the body further defining a channel coannular with the bore, the channel comprising an axially outer edge defining a seat retention groove, the seat retention groove comprising a metal barrier; an annular valve seat positioned in the channel, the valve seat comprising a radially inner surface; and a valve element positioned in the bore and coupled to the body, the valve element comprising a rotatable disc configured to rotate about and between a closed position, in which the rotatable disc is configured to prevent fluid from flowing through the valve, and an open position, in which the rotatable disc is configured to allow maximum fluid flow through the valve, the radially inner surface of the valve seat configured to seal against the rotatable disc in the closed position.

The invention relates to a closure device (28) for a filter unit (1) for the mutual and releasable insertion into a return air duct or exhaust air duct (2) of a barrier system (3), comprising a main body (30), an opening (6) in the main body (30) that can be peripherally bounded by an annular seal (11), a lid (10) that can be switched between an open position in which the opening (6) is open and a closed position in which it bears in a sealing manner against the annular seal (11) in order to selectively open and close the opening (6) and that has passing through it an imaginary longitudinal axis (A), wherein the lid (10) is connected in an articulated manner to the main body (30) so as to be able to pivot by means of at least one rotary articulation (40) through which there passes a pivot axis (S). The lid (10) is designed so as to be able to pivot at least double-eccentrically, wherein the first eccentricity arises from the fact that the pivot axis (S) is arranged at a distance (A.sub.1) from a plane (E.sub.1) in which a closure section ( ) of the lid (10) lies, and wherein the second eccentricity arises from the fact that the pivot axis (S) is arranged at a distance (A.sub.2) from a vertical longitudinal mid-plane (E.sub.2) which passes vertically through the center of the lid (10) when the latter is in its closed position.

Example aspects of a valve are disclosed. The valve can comprise a valve body defining a first end, a second end opposite the first end, an inner surface, and an outer surface, the inner surface defining a body bore extending from the first end to the second end and a channel extending radially outward from the body bore, the channel defining a seat retention groove; a metal barrier applied to the inner surface and covering the seat retention groove, the metal barrier defining a first edge and a second edge, the first edge oriented between the seat retention groove and the first end, and the second edge oriented between the seat retention groove and the second end; and a valve seat positioned within the channel.

An improved butterfly valve having (a) a valve housing, (b) a valve-plate having a peripheral edge located in a central plane when in a fully-closed position, (c) a valve stem configured to rotate the valve-plate about an axis parallel to the central plane to control flow through the valve, and (d) a valve seat configured to engage the peripheral edge to form a seal when the valve-plate is in closed positions, the improvement wherein the valve seat comprises (1) a resilient sealing member having an inward valve-seating surface engaging the peripheral edge therearound and an opposite outward surface; and (2) a ring structure: (i) having an inner surface adjacent to the outward surface; (ii) having the valve stem passing therethrough along the axis; (iii) divided into two sub-ring portions adjacent to each other with valve-stem-adjacent ends; and (iv) sized to permit central-plane-parallel relative sub-ring-portion displacement perpendicular to the axis, thereby lowering valve actuation force.

Disclosed is a valve comprising: an annular body defining a body bore having a bore axis, the body further defining a channel coannular with the bore, the channel comprising an axially outer edge defining a seat retention groove, the seat retention groove comprising a metal barrier; an annular valve seat positioned in the channel, the valve seat comprising a radially inner surface; and a valve element positioned in the bore and coupled to the body, the valve element comprising a rotatable disc configured to rotate about and between a closed position, in which the rotatable disc is configured to prevent fluid from flowing through the valve, and an open position, in which the rotatable disc is configured to allow maximum fluid flow through the valve, the radially inner surface of the valve seat configured to seal against the rotatable disc in the closed position.