Abstract: A controlled atmosphere furnace having radiant heating tubes, through which hot gases from a fuel burner are passed, is converted to electrical operation by removing the fuel burner and exhaust connections from the heating tubes and replacing these with electrical connector extensions connected to an electrical power source so that electrical current is driven longitudinally through the heating tube walls and converted therein to heat which is radiated into the furnace enclosure.

Abstract: A preheating arrangement for bringing foundry ladles up to temperature is described. The arrangement comprises a slotted elongated graphite rod extending down from a ladle cover, a pair of clamp and contact elements extending through the cover and a transformer above the cover with a shell around the transformer forming a single turn secondary winding connected directly to the clamp and contact elements. A graphite element is coated to protect it from corrosive atmospheres by heating it, while buried in sand, to the fusing temperature of the sand and then allowing it to cool.