GB582429A - Improvements in method and means for improving blast furnace operations - Google Patents

Abstract

582,429. Blast furnaces. UNITED STATES STEEL CORPORATION OF DELAWARE. Dec. 13, 1943, No.20854. Convention date, June 22. [Class 72] [Also in Groups XXXV and XXXVIII] Means are provided in a blast furnace for automatically regulating the temperature of the hot air blast to compensate for fluctuations in the humidity of the cold air supply. As shown, a sample of air taken from the blower intake is passed through a chamber 9 which is kept at a constant temperature and contains a thermopile 14 the alternate junctions of which are moistened by a water spray and whose output thus depends on the humidity of the sample. Under normal conditions, the voltage developed by a thermocouple 16 in the hot air main together with a portion of the voltage developed by thermopile 14 should balance the voltage across resistor 31 and that part of a slide wire below its contact 33. A change in humidity or temperature will unbalance the voltages causing relay 20 to deflect and by closing contacts 22 or 23 cause rotor 24 to turn until the voltages are balanced again. The rotation of cam 36 by the rotor actuates control arm 45 and energises motor 18 thus closing or opening mixer valve 6 which controls the amount of cold air bye-passed round the air heater 3 and varies the temperature. The position of the cam follower controlling arm 45 and thus the setting of valve 6 can be adjusted by knob 43 to obtain a desired temperature setting for a given humidity. A modification, Fig. 2 (not shown), has a potentiometer controller operating in response to thermopile 14 and controlling the position of a cam follower actuating contact arm 45 and a second controller operating in response to thermocouple 16 to control the position of the cam.