Control apparatus for a continuous cast billet

1,090,303. Automatic attitude control. KOPPERS CO. Inc. May 9, 1966 [June 18, 1965], No.20527/66. Heading G3R. A metal casting continuously withdrawn from a mould by pinch rolls, travels in a curved path to straightener rolls, and deviations from a desired curved path are self-corrected by automatic control of the speed of the straightener rolls. As shown, a metal casting 19, continuously withdrawn from a water-cooled mould 17 by pinch rolls 25 and further cooled at 23, is bent in the form of an arc before entering straightener rolls 29. Metal is supplied to mould 17 from a tun dish 13 and the rate of withdrawal of the casting is made dependent on the level in the mould by a radiation type level detector automatically controlling at 28 the speed of a motor 27 driving the pinch rolls. Variations in the attitude of the casting are detected by a weighted lever 43 which adjusts the core of a transformer 66 so that, if the movement exceeds a predetermined minimum, the voltage applied from a potentiometer 39 controls, through an amplifier 36, the speed of a motor 35 driving the straightener rolls and the casting is restored to a desired attitude. Feedback dependent on the speed of motor 35 is applied to the input of amplifier 36 from a tachogenerator 38 driven by motor 35. A changeover switch 46 is provided so that the basic speed of motor 35 may be adjusted manually by a potentiometer 43 or automatically in dependence on the speed of the pinch rolls by the output of a tachogenerator 42 driven by motor 27. Excessive movement of lever 43 causes operation of limit switches 77, 79 so that an alarm 103 is sounded and, if the casting is pulled too straight, motor 35 is temporarily stopped. Alarm 103 may be silenced by operation of a push button 105. Use of a radiation device instead of a feeler to detect changes in attitude of the casting is referred to.