The hot zone is perhaps the most critical feature of a vacuum furnace in terms of its effect on furnace performance and operating cost. There are a variety of hot zone designs and the choice of a design should be based on a careful analysis of specific processing applications. Most vacuum-furnace hot zones consist of four major components: the heating elements and the details on which they are mounted; the insulation package (or heat shields); a surrounding structure that supports the heating elements and insulation package; and a hearth that supports the load during processing.
Most vacuum-furnace hot zones consist of four major components: the heating elements and the details on which they are mounted; the insulation package (or heat shields); a surrounding structure that supports the heating elements and insulation package; and a hearth that supports the load during processing. A hot zone can be constructed in either rectangular or cylindrical form, with the latter being far more prominent in vacuum furnaces today. All hot zones are constructed in modular form for ease of installation into and removal from the vacuum chamber. BY JEFF PRITCHARD