Two standard variations of ceramic insulation for box furnaces are rigid ceramic fiber boards and flexible blankets. They are manufactured using strands of refractory silicate compressed or woven into a lightweight textile, with excellent inherent strength and low thermal conductivity. Ceramic fiber board is often used as a secondary form of insulation in box furnaces to support the performance of flat plate heaters. As an alternative, a flat plate heater — a composite heating element and insulation product — can be supplied that exploits the low thermal mass of ceramic insulation to optimize the radiation of heat through a processing chamber. This utilizes a cast plate ceramic with grooves designed to house wire heaters, which may be fully embedded or partially exposed. Typical heating elements include helical coils, rod overbend and ribbon heaters.

Thermcraft Inc.