OCR Text |
Show I ELECTRIC FURNACES !! An ectrlc furnace for the heat treatment of stool used In automobile construction has been Introduced. Its method of producing uniform, dependable heat that Is bo urgently sought by automobile manufacturers Is quite novel in electric elec-tric furnace practico, although Its principle la comparablo to that of the well-known Nornst lamp. Both the floor and the domelike covers of this furnace are of a refractory material which Ib practically nonconducting at ordinary temperatures. tempera-tures. To start the furnace, a current is passed through a bed of coke laid on Its floor. On belli-sufllclently belli-sufllclently heated the floor becomes a conductor and In turn heats tho wall and top, rendering them conductive, until finally the entire furnace becomes Incandescent. It Is Btated by those who have tried the furnace that ita use In tho heat treatment of automobllo parts promises to be cxtonslve In tho futuro. |