METHOD FOR CONTROLLING FLOW RATE OF GAS TO BE BLOWN TO REFINING FURNACE

摘要

PURPOSE:To speed up the rise and fall of the flow rate of gas to improve a transient response characteristic in the stage of changing considerably the flow rate of the gas to be blown by changing over the set value after the change of said flow rate to the set value of an excessive flow rate and controlling the flow rate to a constant rate when the changed set value is attained. CONSTITUTION:The gas A past a flow rate control valve 16 is blown through a tuyere 12 into a converter 10 at the flow rate controlled to the set flow rate value. A change- over circuit 24A changes over the flow rate to the max. set value and outputs the same to a flow rate controller 22A to control the flow rate to the max. value in the stage of increasing considerably the flow rate of the gas A. Then the back pressure of the tuyere increases and therefore the pressure increase is detected by a pressure gage 20. The circuit 24A changes over the max. set value to the set value after the change by the command of a pressure controller 21. The controller 22A controls the flow rate to the constant rate by the changed set value. The set value is changed over to the min. set value by the similar operation and the control to the constant flow rate is executed after the set value is returned to the changed set value in the case of decreasing considerably the gas A.