Patent ID: 7001497

Claim:
A process for replacing anodes in an electrolysis cell comprising a bus bar and at least one anode having an anode rod connected with said bus bar, comprising the steps: (a) calculating a desired distance (D 4 ) from said bus bar to a reference point on or adjacent to an anode rod for a new anode to replace a spent anode in said cell, where the bus bar is chosen as an absolute reference for vertical positioning, said calculation comprising the steps: (1) measuring a first distance (D 1 ) from said bus bar to a reference point on or adjacent to an anode rod for said spent anode, (2) measuring a second distance (D 2 ) from a suitable location on or adjacent to a bottom of said spent anode to said reference point on or adjacent to said anode rod for the spent anode, (3) measuring a third distance (D 3 ) from a suitable location on or adjacent to a bottom of said new anode to said reference point on or adjacent to said anode rod for the new anode, and (4) calculating said desired distance (D 4 ) as follows: D 4 =D 3 −D 2 +D 1 +X, wherein X is a predetermined distance between said bottom for the spent anode and said bottom for the new anode, (b) replacing said spent anode with said new anode so that said reference point is spaced from the bus bar by an actual distance (D 5 ), (c) measuring said actual distance (D 5 ) by means of at least one laser distance detector associated with and sending signals to a programmable logic controller (PLC) which compares the actual distance (D 5 ) with the desired distance (D 4 ) and controls raising or lowering the new anode, and, (d) repeating step (c) at least once, to reduce the distance between the actual distance (D 5 ) and the desired distance (D 4 ) to an acceptable level.