Abstract: A high temperature vacuum furnace has a circulating path external to the heating chamber for facilitating inert gas circulation during initial convection heating of a high temperature vacuum furnace. The heating chamber of the furnace and a surrounding cooling gas introduction chamber are within a metallic convection shroud in such a way that the space in between defines a heating gas circulation chamber for circulating heated inert gas during low temperature heating for accelerating the heating-up of the hot zone to its normal operating temperatures. Once the hot zone has reached a selected temperature, the inert gas is pumped out and the furnace then operates in a vacuum. Quenching is achieved by introducing cooling gas into the heating chamber via nozzles through the heating chamber walls.

Abstract: A vacuum furnace has a heating chamber heated by metal strip electric heater elements. The elements have insulated mechanical support between their ends to hold them in position in the furnace. Support is provided by assemblies having spaced apart mounting assemblies with a rigid bridge compliantly mounted therebetween. The heater strip is compliantly connected to the bridge. Each mounting assembly has a metal post connected to the furnace heating chamber and surrounded by a ceramic sleeve. The ceramic sleeve is surrounded by two ceramic tubes which hold an end of the bridge therebetween.