Baking synthetic carbon mouldings by resistance heating - esp. in mfg. large anodes for producing aluminium by electrolysis of molten salt

摘要

This is an addn. to 2906678, which described the electric resistance heating of a preformed green moulding using at least two electric circuits adjusted w.r.t. each other. The novelty in the present invention is that the electric currents in the circuits are coupled via one or more choke coils so that the total excitation, obtd. by the sum of the prods. of vector currents times number of turns, is zero. The pref. heating plant uses several pairs of electrodes in contact with a carbon moulding, and connected via leads with the sec. windings of at least one transformer, choke coils being provided in the leads. Uniform distribution of electric current in the moulding is obtd. so baking is homogeneous.