Patent GB-647606-A (GB)
Title: Improvements in or relating to metal strip rolling mills
IPC: B21B37/28
Filed: 1948-06-02
Abstract: 647,606. Automatic control systems. COOKE, E. A., and KAPELLA, Ltd. June 2, 1948, Nos. 14918/48 and 5842/49. [Class 38 (iv)] [Also in Groups XXII, XXIX and XXXVIII] Control apparatus for a metal strip rolling- mill comprises means whereby the effective loading of the work rolls is so controlled automatically in accordance with the thickness of the strip, before or after the pass, that any departure of the thickness of the strip from a given value produces a change in the effective loading which is proportional to the said departure. Backing roll A4 is hydraulically loaded through conduits E1, E2, by pumps C, D, of the kind forming the subject of Specification 577,016, [Group XXIX], and each comprising a plurality of plungers C3 operated by a swash-plate C4, which may be angularly adjusted to vary the output of the pump. The conduits communicate with cylinders F1, G1 of pressure control valves F and G respectively, each containing a byepass control lever F5, pivoted on a diaphragm F4. That portion of the lever on one side of the diaphragm cooperates with the stem F3 of a plunger F2 and is urged towards a byepass orifice C6 by a spring H1, adjustably loaded by a rod H3, so that movement of the plunger F2 reduces or increases the flow of liquid through the orifice C6 from a vented servo-sylinder C8 and the resulting movement of the servo-piston C9 and the associated swash-plate C4 increases or decreases the delivery of the pump. The other end of the lever co-operates with an adjustable stop F6 and carries an armature F7 movable within a solenoid F8. Two electromagnetic gauges J, K, as described, for example, in Specifications 541,627, 556,607 and 561,141, [all in Group XXXVIII], are provided, one before and one behind the work rolls, and connected to a changeover switch L, whereby either J or K operates on the control valves F and G, through the medium of an electronic amplifier M whose output, is varied by the respective gauge J or K. This output is connected to the solenoids F8, G8 whose energization is correspondingly modified, thereby causing the control levers F5 to modify the pump delivery pressure. That gauge J or K not operative upon the control valves is connected to a power unit N, which may be as described in Specification 541,627, [Group XXXVIII], to indicate thickness variations on a microammeter P9. Since it will not be practicable under all conditions to operate effectively with equal pressures in the cylinders A7, A8, differential pressure adjusting means R enable the datum pressure of each cylinder to be fixed independently of the other. Operation of rotary knobs S1, S2, moves blocks R4, causing links R1, R2 to move the load control rods H3, H4, thereby increasing or decreasing the loading of the springs HI, H2, and, so increasing or decreasing the hydraulic pressure required to maintain the respective control lever F5 in equilibrium. Operation of a hand wheel S causes both links R1, R2 to pivot about pivots R3 and lowers or raises the datum pressure for both cylinders A7, A8 simultaneously whilst maintaining any differential settings which may have been applied through knobs S1, S2. Specifications 541,628 and 549,987, [Group XXXVIII], also are referred to.