GB1456979A - Process and apparatus for automatically controlling an oxygen top-blowing process - Google Patents

Abstract

1456979 Controlling top-blown converter SIEMENS AG and FRIED KRUPP GmbH 10 Dec 1973 [8 Dec 1972] 57213/73 Heading C7D In a top-blown converter process the oxygen distribution is monitored and any deviation from a predetermined value, or change in the latter caused to alter the lance height through a control loop. Furthermore the deviation and its rate of change are also monitored whereby when the deviation exceeds a pre-set limit the control loop is overridden and the lance moved by an alternative system to a position determined by the magnitude of the deviation, control then reverting to the primary system after a predetermined delay; when the deviation does not exceed the limit, and is decreasing at or above a pre-set rate, the gain of the primary controller is brought to zero, but is given a finite value above that rate. As particularly described the oxygen distribution value 11 is compared at 5 with target value 13 and caused to operate primary controller 1. If the deviation is excessive unit 4 transfers control to open loop unit 3, the action of the latter being blocked by comparator 6 unless the magnitude of the adjustment is above a threshold value. The gain of controller 1 is adjusted by circuit 14 while a further controller 2 is responsible for oxygen flow, the oxygen flow and lance height systems being inter-connected.