Patent GB-558130-A (GB)
Title: Improved method of and apparatus for electroplating sheet metal
IPC: C25D7/06
Filed: 1942-06-18
Abstract: 558,130. Electroplating sheet metal. CROWN CORK & SEAL CO., Inc. June 18, 1942, No. 8391. Convention date, Dec. 24, 1941. [Class 41] Apparatus for producing tin-plate or other electroplated sheet metal in a continuous process comprises means for drawing the metal from rolls and welding the ends of the lengths together to form a continuous strip, a roller looping device for compensating for the interruptions or delays due to welding and ensuring a feed of the strip at constant speed, pickling, rinsing, plating, and further rinsing tanks, arrangements being made so that the sheet is covered with a protective liquid film in its passage from one tank to the next so as to, prevent oxidation, drying, further looping, severing and rewinding devices ; the operation normally affords coated metal having a dull or matt finish but optionally means for fluxing, rinsing and burnishing the plated sheet by heating and quenching in water may be provided. The metal stock, drawn from one or other of the supply rolls 11, Fig. 1, passes to a welder 12 where the lengths from the rolls are joined into a continuous strip, through power-operated pinch rolls 57 to a looping device 13 and then in turn through pickling, rinsing, plating, and further rinsing tanks 14 ... 17, to a dryer 18, and through a second looping device 19 which compensates for delays during the severing of the strip during the re-winding of the lengths into rolls in the re-winding device 20. The rolls 11, carried on a wheeled truck 25 running on rails, are brought into position adjacent to the cradle 34 and by cam-actuated tilting of the supporting platform 28 are transferred to one or other of them and by appropriate hydraulic or electric means are raised and supported for rotation in adjustable coned bearing members. After being connected into a continuous web in the welder 12 the sheets are drawn by the rolls 57 to the looper 13 comprising standards 58 on which are disposed a lower fixed and a slidable weight-actuated upper bracket (not shown) each carrying rollers between which a supply of the metal strip is collected. From the looper the strip passes over rubber-covered rolls in a rubber-lined heated tank 14 containing a preferably acid pickling. solution, following which it is rinsed, in cold water in a partitioned tank 15, being sprayed with water on both sides as it enters over roll 81, and on. one or both sides as it leaves over roll 87, the washings in each case being directed into tank 15 by troughs 83, 89. Before entering the plating tank 16 the under surface of the strip is engaged by a. soft brush 90, the upper surface also being brushed if desired, after which it passes through a pair of wringer rolls, the lower one of which is the first of a series of currentcarrier rolls 92 for the plating bath. Rubber contact rolls 94 and adjustable scrapers (not shown) are provided for the conductor rolls and insulated rubber-covered rollers. 95 over which the strip passes at the bottom of the tank. The strip passes between T- shaped tin anodes 103 supported on conveyers 105 mounted, on sprockets 107 ; by movement of the conveyer the anodes can in. turn be brought. to, a suitable, position for removal and replacement by a travelling crane 109. For tin, an aqueous electrolyte of sodium stannate, acetate, cyanide, and caustic soda is employed. Electrolyte from the bath and sludge from the pockets 110 can be drained into tank 112. and the solution restored to the bath, the tin in the sludge being reclaimed by heating with fused NaOH and treating with water to get the tin in solution. Current is supplied to the shafts of the rolls 92 through bushmgs mounted on and insulated from the tank. The strip leaves the plating bath over rolls 134, 135, 136, the last pair being water-sprayed and the washings directed back into the bath by a trough 137, and passes to a hot water rinsing tank 17 over roll 139 and past hot-water sprays, leaving between similar sprays 141 and passing between rolls 142 to a hot-air drier 18, from which it passes through a set of driven pinch rolls 147 to a second looper 19 and so past drag rolls 150 to the re-winding device 20 where severing of the strip to reform separate lengths is effected. The re-winder comprises a railed carriage 161 movably mounted on a base 160; it comprises a motordriven re-winding mandrel the rolls formed on which are after severing transferred to wheeled coil-receiving trucks 163 which are moved along the rails to deposit the wound coils on platform P. If a bright finish is desired the strip is either cold rolled or preferably submitted to a burnishing step which may follow the coating operation directly but is preferably applied to the wound coils of coated metal. From these the strip is fed through pinch rolls, welder, and looper as described above through heated fluxing and washing tanks to a fusing tower 207, Fig. 19a, passing up the pre-heating leg A, which may be heated by the combustion products of gas burners 212 in the fusing leg B, through which the strip passes downwardly; alternatively electric heating may be employed. From leg B the strip passes to a cold-water quenching tank 216, through a hot water tank 219, past hot-air driers 222 and thence via pinch rolls, looper, a branner and straightening rolls to severing and re-winding means. Specifications 259,200, [Class I (ii)], 503,475, 513,246 and 529,247 are referred to.