tin 3,723,285 [45] Mar. 27,1973
[54] SYSTEM FOR PROTECTING
ELECTROLYTIC CELLS AGAINST
SHORT CIRCUITS
[751 Inventors: Giorgio Abbate Daga; Lino Cerrocchi; Pietro Fracassi, all of Milan, Italy
[73] Assignee: Montecatini Edison S.p.A.; Guardigli S.p.A., both of Milan, Italy
[22] Filed: Oct. 13,1970
[21] Appl. No.: 80,433
[30] Foreign Application Priority Data
Oct. 16, 1969 Italy 23449 A/69
[52] U.S. CI 204/228, 204/219, 204/250
[51 ] Int. CI BOlk 3/00, C22d 1/04
[58] Field of Search 204/99, 219-220,
204/225,228,250
[56] References Cited
UNITED STATES PATENTS
3,531,392 9/1970 Schmeiser 204/225
3,574,073 4/1971 Ralston, Jr 204/225
3,476,660 11 /1969 Selwa 204/219 X
3,558,454 1/1971 Schaferetal 204/99
3,462,356 8/1969 Wallinder 204/228
3,594,300 7/1971 Schafer....: 204/225
Primary Examiner—John H. Mack
Assistant Examiner—D. R. Valentine
Attorney—Stevens, Davis, Miller & Mosher
[57] ABSTRACT
A device for protecting electrolytic cells against short circuits, having an operational amplifier for each of the ascent bars of said cells, said amplifiers having adjustable gain and being supplied through difference inputs with voltage falls picked up on said bars, circuits being included for compensating the effects due to temperature variations of the bars as well as circuits for the rejection of the common mode voltages due to anodic transversal voltages, the output voltages from said operational amplifiers supplying an averaging circuit for determining the average voltage and a discriminating circuit for determining the highest voltage, the outputs of said averaging and discriminating circuits terminating at a comparator circuit in its turn associated with an alarm and/or control unit.
18 Claims, 3 Drawing Figures
