| 摘要 |
<p>1476695 Aluminium production by fusion electrolysis REYNOLDS METALS CO 17 Sept 1974 [17 Sept 1973] 40477/74 Heading C7B In an alumina reduction cell, Fig. 1, maladjustment of an anode 11, which is allowing. current to be transmitted without contributing to the reduction, such as when the anode is, incipiently, grounded, is detected by comparing a measured value representing the number of sinusoidal fluctuations occurring in the anode current within a given time interval with a reference value representing the number of fluctuations due to formation and release of gas bubbles 32, 33 when the anode is correctly adjusted and generating a signal when the measured value is less than the reference value i.e. indicating a lower frequency fluctuation. The measured value may be obtained by producing a stem voltage, e.g. from leads 38, 40 on each Cu stem 12 connected by metal stub 14 cast in each C block anode 11, varying with the anode current, and preferably filtered to remove fluctuations at frequencies above and below a selected range, converting the varying voltage fed via leads 201, 202, Fig. 2, and amplifier 208 into a sequence of pulses having a frequency proportional to the fluctuation rate in current, in pulse shaper 203 and counting the pulses over the time interval in counter 213. The reference value may be developed from the voltage by use of a voltage to frequency converter 205, a digital counter 211. A digital comparator 219 is connected to the counters 211, 213. The anode stems 12 are connected to anode bus 16 by clamps 18 and lifted by motor driven bridge jack 19 attached to the cell frame 21. The C cathode 26 contacting the molten Al 30 are connected by collectors 24 to cathode bus 23.</p> |
