Abstract: In a throat stopper for shaft furnaces, in particular blast furnaces with two hoppers of which an upper hopper is rotatable through a drive device, the upper hopper is designed, by a stationary hood equipped with charging flap valves, as a sluice chamber to be closed pressureproof. For sealing the stationary hood relative to the rotatable upper hopper, there is disposed, at the hood, a peripheral flexible inflatable bellows. The bellows can be pressed against the wall of the upper hopper pneumatically or hydraulically. While material is being charged in the upper hopper, one of the charging valves is open and the bellows is pressureless. During, or shortly after, the charging, the uppr hopper is rotated. For filling the lower hopper, the valves of the upper hopper are closed, bellows is inflated, and the upper sluice chamber is pressurized.

Abstract: In a throat stopper for shaft furnaces, in particular blast furnaces with two hoppers of which an upper hopper is rotatable through a drive device, the upper hopper is designed, by means of a stationary hood equipped with charging flap valves, as a sluice chamber to be closed pressureproof. For sealing the stationary hood relative to the rotatable upper hopper, there is disposed, at the hood, a peripheral flexible inflatable bellows. The bellows can be pressed against the wall of the upper hopper pneumatically or hydraulically. While material is being charged in the upper hopper, one of the charging valves is open and the bellows is pressureless. During, or shortly thereafter, the charging, the upper hopper is rotated. For during the lower hopper, the valves of the upper hopper are closed, bellows is inflated, and the upper hopper is hopper are closed, bellows is inflated, and the upper sluice chamber is pressurized.