Method and apparatus for forming valve metal foil

Claim 1

A PROCESS FOR PLACING AN OXIDE FILM UPON A VERY THIN METAL FOIL WHICH PROCESS COMPRISES: PASSING A METAL FOIL HAVING SIDES CONSISTING OF METAL SELECTED FROM THE GROUP CONSISTING OF ALUMINUM AND TATALUM IN ONE DIRECTION THROUGH AN ENCLOSED FORMING CHANNEL HAVING CATHODE MEANS LOCATED THEREIN SO AS TO BE SPACED FROM BOTH SIDES OF SAID METAL FOIL, SAID METAL FOIL BEING SPACED FROM SAID CHANNEL AND SAID CATHODE MEANS DURING MOVEMENT THROUGH SAID CHANNEL, PASSING AN ELECTROLYTE THROUGH SAID FORMING CHANNEL IN THE SAME DIRECTION AT A FASTER RATE THAN THE RATE AT WHICH SAID METAL FOIL IS PASSED THROUGH SAID CHANNEL AND AT A TURBULENT VELOCITY WHILE SIMULTANEOUSLY PASSING SAID METAL FOIL THROUGH SAID CHANNEL, SAID ELECTROLYTE BEING PASSED THROUGH SAID CHANNEL SO THAT THE FORCES EXERTED ON THE SIDES OF SAID METAL FOIL THROUGHOUT THE ENTIRE LENGTH OF SAID CHANNEL ARE SUBSTANTIALLY EQUAL ON BOTH SIDES OF SAID METAL FOIL AT ANY POINT ALONG THE LENGTH OF SAID METAL FOIL AND SO THAT SAID ELECTROLYTE SERVES TO MAINTAIN SAID METAL FOIL IN THROUGH SAID CONDITION DURING MOVEMENT OF SAID METAL FOIL AN UNBENT FORMING CHANNEL, AND APPLYING CURRENT TO SAID CATHODE MEANS AND TO SAID METAL FOIL WHEREBY SAID METAL FOIL IS OXIDIZED IN SAID FORMING CHANNEL, SAID ELECTROLYTE FLOW AT A TURBULENT VELOCITY CAUSING SUBSTANTIALLY COMPLETE INTERMIXTURE OF SAID ELECTROLYTE WITHIN SAID CHANNEL SO AS TO PREVENT THE ACCUMULATION OF SURFACE IMPURTITIES ON SAID CATHODE MEANS, SO AS TO CAUSE UNIFORM ELECTRO-CHEMICAL CONDITIONS WITHIN SAID CHANNEL AND SO AS TO PREVENT HEAT BUILD UP WITHIN SAID FORMING CHANNEL.