Patent ID: 6797230
Filing Date: 2004-09-28
Classification: B22D,C21C

Abstract:
A gas bubbler stone for metallurgical vessels comprising:a porous, gas-permeable molded stone made of a refractory material, a gastight partial sheathing enclosing it, made of a metal casing which extends around the lateral peripheral surface of the molded stone and a sheet metal cover which covers the outer end face of the-molded stone, and a gas delivery pipe which extends from the under side of the sheet metal cover and is joined to the sheet metal cover in the area of a gas inlet opening formed in the sheet metal cover and which has a narrowed cross section at a distance from the gas inlet opening of the sheet metal cover and a closing body which is movable at least in the axial direction of the gas delivery pipe and is situated in the pipe section between the sheet metal cover and the narrowed cross section, its cross section being smaller than the inside diameter of the gas delivery pipe and greater than the narrowed cross section, said closing body, like a non-return valve, being loaded in the direction of the narrowed cross section which defines a valve seat by a helical compression spring which is supported on the sheet metal cover, wherein a free annular clearance is provided between the inside wall of the gas delivery pipe and the helical compression spring and the cross section of the gas inlet opening at least partially overlaps the cross section of the free annular clearance.