GB1241712A - A control device for rolling mills - Google Patents

Abstract

1,241,712. Automatic control of rolling mills. HITACHI Ltd. June 16, 1969 [June 19, 1968], No.30461/69. Heading G3R. In a system for controlling the gap in a rolling mill in response to a combination of the target thickness ho of rolled material, the roll pressure and the mill spring constant M, the latter is computed at intervals from measurements of the gap, the pressure and the actual thickness. Measurements of the roll gap and pressure from devices 3 and 4 respectively are supplied to memory circuits 11, 12 via a gate 10 which is opened briefly by a differentiating circuit 18 which responds to the change over of a flip-flop 15. Similarly, a measurement of actual thickness from an X-ray gauge 6 is supplied to a memory 17 via a gate 16 controlled by a second differentiator 19 responsive to the flip-flop changing in the opposite sense. Change-over occurs when an integrator or pulse counter 9 supplied with voltage or pulses from a tachogenerator 8 has determined that the material between the rolls when the gate 10 opened has reached the X-ray gauge 6. Thus, all the measurements stored in the memory circuits relate to the same cross-section of material. From these measurements a computer 13 calculates M, the spring constant, which is thus updated at intervals corresponding to the transit time from the rolls to the gauge. The most recent value of M is stored in another memory 14 and is used by a roll gap control computer 7 in the calculation of the required gap to achieve thickness ho. Correction is made either continuously, with each new value of M, or at less frequent intervals.