GB933435A - Improvements in control systems for blast furnaces - Google Patents

Abstract

933,435. Controlling blast furnaces. BAILEY METER CO. May 30, 1962 [June 1, 1961], No. 20757/62. Class 72. [Also in Groups XII and XXIX] The amount of fuel injected into a blast furnace is automatically regulated to maintain the top gas issuing from the furnace of constant composition. A device 38 produces a pressure proportional to the amount of at least one combustible constituent of the flue gas, which is applied through a relay 40 and a manual/ automatic selector 42 to a relay 43. The relay 43 produces an output pressure dependent on the flue gas composition and is arranged to anticipate changes caused in the flue gas by the changes in the amount of the blast. The blast, which may be oxygen enriched, is regulated by blower motor control unit 33 operated by a fluid pressure relay 27 of the proportional and reset action type described in U.S.A. Specification 2,805,678 through a manual/automatic selector 30 which has an adjustment for the reference value fed to the bellows 27A of relay 27. A pressure from the blast flow controller 25 is applied to the relay 43 as well as to the air flow control relay 27. The output pressure from relay 43 is supplied to the fuel flow control relay 48 together with an output from the fuel flow controller 47. The relay 48 controls a valve 46 in the fuel supply line. A hot air store by-pass valve 17 may be operated manually or automatically to compensate for the drop in blast temperature caused by the fuel input. The fuel supply to each tuyere may be controlled individually.