GB1237287A - Rolling mill control system - Google Patents

Abstract

1,237,287. Rolling mills. KAISER ALUMINUM & CHEMICAL CORP. 9 Sept., 1968, No. 42872/68. Heading B3M. [Also in Division G3] A desired roll gap is maintained in a rolling mill by the operation of separate hydraulic prestressing and roll bending systems, the systems being interlocked for interdependent operation. In a 4-high arrangement, cylinders 33 urge the lower backing roll 14 upwardly with a constant force. The force is held constant by a feedback system incorporating, for each side of the mill, a load cell 76 which measures the force on the roll, using rods 74, a potentiometer 72 for setting a desired force, and an amplifier 70 which controls a valve 66 to reduce any difference between the measured and desired values of force. A similar feedback system controls the pressure exerted in bending cylinders 42, a potentiometer 74<SP>1</SP> setting a desired pressure, and a sensor 82 measuring the actual load. The amplifier 76<SP>1</SP> which controls the bending pressure has a further, adjustable, input from an auxiliary summing amplifier 86. The amplifier 86 is provided with pressure signals from both the feedback systems and serves to make the systems interdependent. In an alternative control system (Fig. 3, not shown), the measuring rods 74 and load cells 76 are dispensed with, and the operation of the prestressing control valves 66 is dependent on the pressures in the prestressing cylinders 33 and on the bending pressures in the cylinders 42. The work rolls of a 2-high mill may be controllably bowed using the invention.