Induction furnace for oxidation - uses radiation from steel rod to preheat zircon tube to temp. adequate for inductive coupling

摘要

The induction furnace (c. 2000 degrees C) for heating materials in an oxidising atmosphere, consists of a zircon heating tube around which is wound a cylindrical inductor. The tube is surrounded by thermally insulating material. Since zircon has a high resistance at room temp. it is necessary to reduce this resistance before inductive coupling can take place between the inductor and the zircon tube. This is achieved by inserting a refractory non-oxidisable steel rod into the furnace. The rod is heated by induction and heats the zircon tube by radiation. When the zircon tube's temp. is high enough for inductive coupling to the inductor the steel rod is withdrawn. The charge can then be introduced and heated by radition from the now inductively heated zircon tube.