serve essentially to avoid heat losses, and as safety devices for the operating per- sonnel, to screen them against the heat radiation and prevent the danger of falling. Furnace covers are made of steel plate with a ceramic cladding, which is as a rule cast. An imaginary furnace cover is et in place under processor opera- tion of a crucible furnace at he end of the melting process, and all stored values of the melt are processed, and displayed on the screen or printed out for the information of the operator (ready for further measures).
Larger furnaces with cover diameters of over approx. 1,200 mm have an addi- tional small cover that can be swung open by hand. Through this opening, addi- tives can be added to the melt or the temperature measured.