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.

The disclosure relates to a unitary disc-stem apparatus for a valve, which has a disc defining a circumference around the disc; a first hub integral to the disc; a second hub integral to the disc; a first stem portion joining the disc at the first hub and a second stem portion joining to the disc at the second hub; a curved extended edge which is transposed on opposite sides of the disc, wherein the curved extended edge is progressively longer moving circumferentially away from the first hub and the second hub along the circumference of the disc, and longest at a position where the opposite curved extended edges of the disc are along an axis perpendicular to the first stem portion and the second stem portion.

A soft-sealing, concentric butterfly valve for mounting with grooved couplings or flanges in a pipe system. The butterfly valve comprising a valve housing with a through running boring with a rotary damper, mounted to a spindle placed upright in a circular-cylindrical valve seat, said valve seat being equipped internally with conical contact surfaces for the damper, and the valve housing comprises on a first side a coupling end piece cast in one piece with the valve housing and equipped with an external circular groove. The valve has a removable coupling part, comprising a second coupling end piece equipped with an external circular groove, mounted to said second side of the valve housing, and said valve seat is compressed between the valve housing and the removable coupling part and surrounds the damper to provide a leak proof connection.

A valve seat includes an annular sealing surface comprising a rubber-lubricant mixture; and a seat body. A valve includes a valve body; a valve element disposed within the valve body; and a valve seat comprising a rubber-lubricant mixture, the valve element configured to seal against the valve seat. A method for forming a valve seat includes mixing a raw rubber with a lubricant to form a rubber-lubricant mixture; placing the rubber-lubricant mixture into a mold configured to form a valve seat; and curing the rubber-lubricant mixture.

The invention is a butterfly valve assembly for above-ground pipelines wherein the valve assembly is inserted between adjacent pipe sections, the pipe sections terminating in a pipe flange. The invention has a valve body which can be directly attached to the pipe flanges of adjacent pipe sections by welding, for example. The valve body includes first and second flange abutment members which align with the flanges of the adjacent pipe sections and can be permanently fastened to the flanges. The butterfly valve and valve seal can be removed from the valve body and replaced or serviced without having detach the remainder of the valve body from the pipeline.

A valve assembly having a valve housing, the valve housing defining a passageway. A flapper valve arranged within the passageway is coupled to a rotatable valve shaft. A flexible wall, sealed along opposed edges to the valve housing, is controllable to at least two positions. The first position seals against the flapper valve and the second position releases the flapper valve allowing for ready movement of the valve.

A replaceable seat is provided for a convertible check valve. The convertible check valve includes a first valve body section having a first passageway and a first flange, and a second valve body section having a second passageway and a second flange. The second flange is configured for connection to the first flange. The check valve also includes a flapper that moves between a closed state and an opened state. The flapper prevents flow between the first passageway and the second passageway when the flapper is in the closed state. The check valve also includes a gasket interposed between the first flange and the second flange. The gasket includes an opening to permit fluid communication between the first passageway and the second passageway and a valve seat with an integrated O-ring that is configured to contact the flapper when the flapper is in the closed state.

A butterfly valve includes a valve body with an internal flow passage, a seat ring attached to an inner peripheral surface of the internal flow passage, a valve stem rotatably supported by the valve body, and a valve element rotatably supported by the valve body via the valve stem. The valve element has an annular outer peripheral edge surface, and includes, at opposite positions in the direction of the rotation axis on the outer peripheral edge surface, two valve-stem openings for the valve shaft to pass therethrough. The outer peripheral edge surface of the valve element includes two annular opening raised portions each extending along the periphery of the corresponding valve stem openings, and peripheral edge raised portions connecting the two opening raised portions, each having a peripheral edge sealing surface extending along a top thereof, and chamfered surfaces inclined and extending along both sides of the peripheral sealing surface.

A seat ring for a butterfly valve provided at an inner circumferential surface of a valve body so as to create a seal between the inner circumferential surface of a valve body and the valve disc when closing the valve, and a sealing projection continuously protruding inwardly provided between a pair of bosses formed around a pair of opposite valve stem holes for inserting valve stems positioned radially outwardly of a flow passage direction. The sealing projection consists of a contact surface and an adjacent semi-elliptic surface, wherein the contact line of the contact surface and top portion of the adjacent semi-elliptic surface is a semi-elliptic edge displaced by an offset h from a plane defined by a vertical valve centerline and a transversal valve centerline in disc closing direction.

A mechanical joint includes a main body having an interior surface, an exterior surface, an inlet end, and an outlet end, the interior surface defining a fluid path from the inlet end to the outlet end, the interior surface defining a pipe seat proximate to a one of the inlet end and the outlet end, the pipe seat having a pipe seat stop surface facing towards the one of the inlet end and the outlet end; and a lining engaging the interior surface and covering at least a portion of the pipe seat stop surface of the pipe seat.