Vertical-shaft furnace for the heat-treatment of metallic workpieces

Abstract

A vertical-shaft furnace serves for heat-treating metallic workpieces. It comprises a furnace housing with a heating chamber arranged therein. The heating chamber is provided with a closed wall at its upper end, while its lower end can be opened in order to enable the workpieces, which are to be treated, to be loaded into the heating chamber from below. There are further provided heating means for heating the heating chamber, means for lifting a workpiece carrier from a first lower position below the lower end of the heating chamber into a second upper position inside the heating chamber, the workpiece carrier being suspended on at least one flexible element which is passed through the opening in the upper wall of the heating chamber and connected to a drive outside the heating chamber. The flexible element is provided with a rod-shaped section which in the second upper position of the workpiece carrier extends through the opening and is embraced in this second position by a sealing element in gas-tight relationship. A wall projecting from the sealing element in downward direction surrounds the opening in the upper wall of the heating chamber, which latter is immersed to float in a liquid contained in a double-walled vessel with open top which surrounds the opening in the upper wall of the heating chamber and is firmly connected to that wall at the upper end of the heating chamber.