Improvements relating to the electrolytic production of aluminium

摘要

1,012,790. Automatic control systems for electrolytic cells. SWISS ALUMINIUM Ltd. Aug 17, 1964 [Aug 30, 1963], No. 33525/64. Drawings to Specification. Heading G3R. The terminal voltage of an electrolytic cell is automatically regulated by a control system which is responsive to cell conditions for a short interval, e.g. one minute, of each of a number of successive electrolysis periods of from five to thirty minutes; during each such interval, regulating data is transmitted as required in response to terminal voltages above the desired value but below a threshold level. During the non-regulated part of each electrolysis period the terminal voltage tends to rise, and with the development of the "anode effect" this voltage, at the start of a regulating interval, tends to exceed the threshold level; the control system is then arranged to effect only limited regulation, so that the terminal voltage rises to an upper limiting value above which the system ceases to transmit regulating data. This arrangement allows for the full development of the "anode effect", said to be necessary for the purpose of regenerating the electrolyte. The operation of the system is described graphically with reference to Fig. 1 (not shown), and apparatus which regulates the terminal voltage by adjusting the distance between the electrodes is describedwith reference to Fig. 2 (not shown) which illustrates schematically a suitable arrangement of known control elements. Specification 602,876 is referred to.