GB547689A - Improvements in method and apparatus for heating ingots and the like - Google Patents

Abstract

547,689. Heating ingots and the like. KEENER, S. F., and HOPKINS, J. H. April 18, 1941, No. 5073. Convention date, April 18, 1940. [Classes 51 (i) and 51 (ii)] The heat treatment of metals is effected in a furnace provided with an annular hearth into the centre of which a flue opens and around which ports are provided so that heated gases may be circulated in either direction through the furnace in contact with the metal The ports communicate with an annular duct to which gases enter or leave tangentially by a flue forming part of a hot gas circulating system including burners, electric resistance or other heating elements and a fan. As shown in Figs. 1 and 2, ingots or other metal articles are supported on an annular hearth 11 provided with a flue opening 18 at its centre and ports 31 at its periphery communicating with an annular flue 14 to which gases are supplied tangentially by a flue 26 leading from a mixing chamber 20 in communication with a flue 19 conducting gases from the opening 18 and with a combustion chamber 21. A fan 27 circulates the gases through the furnace and flues in either direction. The ports 31 are provided with pivoted vanes 32 which are adjustable to equalize the flow of gases through the ports. The vanes may be shaped so as to direct the gases upwardly among the articles being treated. In a modification (not shown) the flue 14 may be of involute form. Fig. 6 shows a modification in which the gases enter the furnace upon being reversed through a central perforated vertical duct 50 or a series of vertically spaced frustoconical deflectors 51.