Abstract: The device comprises a main valve-seat of sheet metal having an anchoring flange attached to the valve body and a closure structure which is adapted to cooperate with the valve disk by means of an outer wall forming a curled shell, said closure structure being applied against the convex surface of an auxiliary seat which is in turn applied against the valve body in order to ensure resilient coiling-up of the curled shell when closing the valve, thereby reducing the operating torque of the valve and achieving enhanced leak-tightness in the closed position.

Abstract: The invention provides an annular seating, for valves and cocks comprising a body formed with an axial duct and a movable closure member having a bearing surface associated with the seating. The seating has a metal casing having a hollow cross-section having an anchor part adapted to be held in a recess of the body and an annular closure part having an annular contact surface adapted to co-operate resiliently with the annular bearing surface of the closure member when the seat is in the operating position.