Convection heating system for vacuum furnaces

摘要

A convection heating system includes a hot zone enclosure defining a hot zone and a plurality of gas injection nozzles for injecting a cooling gas into the heat treatment zone of furnace. Each gas injection nozzle may include a flap disposed and pivotally supported therein for substantially preventing the escape of heat from the hot zone during a heating cycle, but for permitting the injection of the cooling gas into the furnace hot zone during a cooling cycle. A gas exit port may be provided and may include a flap pivotally mounted therein for impeding the unforced outward flow of a gas from the heat treatment zone during a heating cycle.