Valve with a metal gasket

Valve comprising an annular body, a butterfly which is mounted therein in a manner rotating at 90°, and an annular metal gasket having an axis and a dynamic-sealing element with a lateral face and main faces, wherein the gasket is interposed between the body and the butterfly while being accommodated in a housing belonging to one of the body and the butterfly, whereas the other of the body and the butterfly forms a seat which is inclined in relation to the axis of the gasket and with which the free lateral face of the dynamic-sealing element of the gasket is in contact when the valve is in a closed position, said dynamic-sealing element being connected by a metal sheet to a spring static-sealing element which is clamped in the housing,

• wherein:
• the metal sheet is flexible;
• the dynamic-sealing element has a first part, on the same side as the static-sealing element, which is in contact with the housing, and a second part, on the same side as the seat, wherein there is a clearance between the housing and the main faces of the dynamic-sealing element, when the said dynamic-sealing element is at a distance from the seat;
• and
• the flexible metal sheet comprises two side-pieces and a ring is interposed between the two side-pieces with clearance between it and each of the side-pieces when the gasket is not subjected to a compressive force in the direction of its axis.