The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 18, 1992
Filed:
Feb. 20, 1990
Comalco Aluminum Ltd., Georgetown, AU;
Abstract
A process for controlling an aluminum smelting cell comprising monitoring the cell voltage and current, alumina dumps, additions, operations and anode to cathode distance movements, continuously calculating the cell resistance and the bath resistivity from said monitored cell voltage and current, monitoring the existence of low frequency and high frequency noise in the voltage of the cell, continuously calculating the time rate of change of resistance of the cell, suspending calculation for a predetermined time when an alumina dump, addition, operation or ACD movement occurs, establishing filtered resistance slope thresholds, determining whether the low frequency noise is above a predetermined threshold, and if so, increasing the filtered slope thresholds for low alumina concentration detection, calculating an alumina inventory from the alumina dumps, determining whether the cell is overfed, and if not feeding alumina to prevent an anode affect, calculating the heat supplied and heat required for aluminum production, calculating the heat available for dissipation, calculating the target heat for the cell, calculating the difference between the available heat and the target heat with respect to time, calculating a running heat inventory from the integral of this difference, establishing a target resistance for the cell and modifying that target resistance to achieve a zero heat integral, checking that the target resistance is an allowable value, and moving the anodes of the cell to establish the new target resistance, estimating the time rate of change of bath resistivity and checking whether resistivity and the derivative are greater than predetermined limits, and if so, adjusting the target heat of the cell to maintain the long term heat balance of the cell.