METHOD AND APPARATUS FOR REGULATING THE MOLTEN METAL LEVEL IN A MOLD OF A CONTINUOUS CASTING INSTALLATION

1449846 Continuous casting CONCAST AG and SCHLOEMANN AG 16 Oct 1973 [17 Oct 1972] 48239/73 Heading B3F [Also in Division G3] In a method of controlling the level of the pool of molten metal 35 in the mould 4 of a continuous casting plant, a detector 5, 6 provides a signal of the actual level for comparison by comparator 13 with a reference signal from 15, a resultant error signal being used to control the flow of metal into the mould, e.g. by adjusting the stopper 3 of a tundish 1, and also being fed via line 20 to a function generator 28 which supplies a speed reference signal to a loop which controls the speed of withdrawal of the incipient casting 7 from the mould, the withdrawal speed reference signal being thereby modified if the rate of change of the level error signal exceeds a preset value. As shown, the withdrawal speed control loop comprises a-motor 24 driving rolls 9 and a tachogenerator 23 providing a feedback signal to a regulator 22. The function generator 28 receives a reference signal from 29 to set the withdrawal speed under normal operating conditions. The signal from the level detector, which is of radio-active type, is also fed to the generator 28 via a line 48 and, if the level reaches a maximum or minimum permitted value, the withdrawal speed reference signal is modified irrespective of the rate of change of the level error signal. The generator 28 includes a feedback unit (43, Fig. 2, not shown) whereby its output on line 31 is compared with its input from the reference source 29. The feedback unit attempts to restore the actual speed reference signal to the desired value from 29 after a time delay to allow the pool level to be restored to its proper value.