GB833073A - System for supplying oxygen to blast furnace tuyeres - Google Patents

Abstract

833,073. Fluid-pressure servomotor control systems. UNITED STATES STEEL CORPORATION. July 22, 1957 [Sept. 13, 19561, No. 23185/57. Class 135. [Also in Group XII] In a system for supplying oxygen to a blast furnace tuyere having a connection to a hot-air blast main, the amount of oxygen supplied to the tuyere is dependent upon the rate of flow through the air blast main and/or the tuyere, the arrangement preferably being such that the oxygen flow is inversely proportional to the air blast flow so that the total oxygen flow through the tuyere is substantially constant. In the arrangement shown, each tuyere 3 has an associated oxygen supply pipe 7 fitted with a regulating valve 10 operated by a fluid-pressure motor 12. The latter is controlled by a pivoted jet tube 18 whose end moves between the ends of the motor fluid supply conduits 24, the movements of tube 18 being controlled by diaphragm motors 15, 16 connected to Venturis 31, 34 in the blast main 2 and tuyere 3 respectively. The ratio of the forces applied by the motors 15, 16 may be varied by adjusting the position of a fuldrum 20, and a proportional control of valve 10 is provided by a lever 27 having an adjustable fulcrum 30, and connected at one end 28 to the valve-actuating mechanism and at the other to motor 16 through a spring 29. In the event of decrease of the air flow through the main 2, or the tuyere 3, e.g. due to partial obstruction by the furnace charge, the motor 12 is operated to cause the valve 10 to permit an increased flow of oxygen through the supply pipe 7. The diaphragm motor 15 may be omitted if desired.