GB927593A - Method for the electrical control of blast furnaces - Google Patents

Abstract

927,593. Electric selective signalling systems. RHEINSTAHL EISENWERKE MULHEIM/ MEIDERICH A.G. Dec. 17, 1959 [Dec. 20, 1958], No. 42980/59. Class 40 (1). The position at which a rotary hopper drops a charge into a blast furnace is controlled by recording the instantaneous value of the angular position of the hopper in a counting mechanism at a control station where it is compared with an adjustable programme of control commands, and means is provided to control successive values of the dropping position in accordance with the control programme. A rotary hopper is charged on one side at a fixed charging point, and as the hopper is rotated the charge moves away from the charging point towards a selected angular position where it is to be dropped into the furnace. A toothed wheel 3 operates a contact 4 to supply a pulse to a counting mechanism 5 for each degree of rotation of the hopper from the charging point. In response to each pulse, counter 5 steps wiper 6 to apply a positive potential to one of the 360 contacts of twelve switches 7-8 whose corresponding contacts are connected in parallel. Assuming that the programme comprises a sequence of twelve different angular positions, these positions are selected in switches 7-8 by suitable positioning of the selector arm. Switch 9 selects switches 7- 8 in succession, and each time the desired angular position is reached a pulse is supplied to relay 10 which opens contact 10<SP>1</SP> to stop hopper-drive motor 2, and at the same time resets counter 5 to zero. Immediately after resetting, counter 5 is again responsive to pulses, so any over-run by motor 2 is compensated for in the next operation. A fresh charge is loaded into the hopper at the point which stops under the charging point, so that the succeeding rotation is again measured from the charging point. Operation of relay 10 also, through contact 10<SP>11</SP> supplies a pulse to counter 11 to step the wiper of switch 12 to the next position, and, for the straight sequence of twelve angular positions, a pulse is supplied to relay 14 on each successive operation of counter 10. Relay 14 resets counter 11 and applies a pulse to counter 15 so that the next position of switch 9 is selected. By varying the position of the selector arm of switch 12, the number of repetitions of each angular position may be varied. Certain commands set in switches 7-8 may be omitted from the sequence by operating switch 16. The Specification mentions the control of temperature and flow rate of the air blast and of temperature, flow rate and pressure of cooling water by means of a similar system.