GB810245A - Method of and apparatus for heat treating coils of metal rod, wire or the like - Google Patents

Abstract

810,245. Heat treatment furnaces. WILSON, L. Oct. 11, 1956 [Oct. 24, 1955], No. 31042/56. Class 51 (2). In a bell furnace for heat treating coils of wire carried by the stem of a spider, the base of the spider rests on vanes forming open-topped passages extending radially from an opening in which a blower is arranged below an annular blower inlet plate which also rests on the vanes. Vanes 10 extend helically outwards from the space surrounding a blower 11, an annular inlet plate 13 resting on the inner ends of the vanes, which may be recessed so that the top surface of plate 13 is flush with the upper edges of the outer part of the vanes 10. Furnace atmosphere drawn in through the centre opening of plate 13 is directed outwardly between the vanes 10 to the outer part of the furnace. Coils of wire C are supported on three spiders comprising an apertured baseplate 15 and a tubular stem 18 which is ribbed or corrugated and has holes 19 to allow the atmosphere to reach the inside. The flow outwards between the vanes 10 induces a secondary atmosphere flow around the coils C through the apertured spider stem and base. In a modification, Fig. 5, a single spider is supported above spacing 'struts 26 and an inlet plate 24 by a grating of concentric rings 30 spaced apart by radial and diagonal webs. In this case the secondary flow passes through the coils and down outside the stem 15 of the spider.