GB800381A - Improvements in and relating to the heating and reheating of ferrous metals - Google Patents

Abstract

800,381. Heat-treating furnaces ; furnace atmospheres. METALLURGICAL OXYGEN PROCESSES, Ltd. Oct. 11, 1956 [Oct. 11, 1955], No. 28979/55. Addition to 606,401. Classes 51 (1) and 51 (2). In a furnace for the heat-treatment of metals in which the fuel is burnt in several stages, gas supplied by a burner 16 is partially burnt in the treatment chamber PC, burnt to a secondary combustion stage in chamber SC surrounding said chamber PC, and completely burnt in a two-part recuperator 22 with air supplied through a duct 31. The upper recuperator section 23 supplies preheated gas to the burner 16 through pipe 18, and the lower section 24 supplies preheated oxygenated air to the burner through pipe 17, a branch 19 supplying the chamber SC through ports 20, 21. Products of primary combustion reach chamber SC through ports 14. Fig. 2 illustrates the gaseous flow to the furnace, gas being supplied through pipe 32 under control of valve 34 and back-pressure valve 33 in front of the recuperator section 23, and of valve 35 and non-return valve 36 near the burner. Air from a fan passes through valve 37 to pipe 31, and through valve 38 and non-return valve 39 to the recuperator section 24, mixing with oxygen supplied through valve 41 and non- return valve 42. Valve 43 and non-return valve 44 regulate the air supply to the burner. Chamber PC may be lined with heat-conducting bricks or with porous refractory bricks.