GB314392A - Method of and means for sectional electro-plating, particularly applicable for plating large objects with chromium - Google Patents

Abstract

314,392. Siemens & Halske Akt.- Ges., (Assignees of Schwartz, K. W.). June 26, 1928, [Convention date]. Drawings to Specification. Chromium and other metals, depositing; metals, pickling; electrodes, moving; connections; electrolytes, circulating, heating, and cooling.- Large objects are electroplated in sections using anodes which are divided into sections insulated from one another and connected to separate supply leads. For chromium-plating the inside of a reaction chamber for oil cracking purposes having a height of 12 metres and a diameter of 3 metres, the anodes are rotated by a spindle introduced through an aperture at the top of the chamber and supported in a bearing in a horizontal plate near the bottom. The anode sections are supported by tubes which serve as protectors for the supply leads, the tubes comprising easilydetachable longitudinal sections, the upper of which are removed successively so as to effect plating of the container in strips from bottom to top. The leads are connected to independent collector rings. Two anode sections lying in the same plane may be provided, one of which is conected to such a voltage that generation of gas without deposition of metal takes place so as to effect cleaning of the cathode, the other anode being connected to a higher voltage for deposition. Curved anode sections are provided for plating the ends of the container; these may be connected so as to produce a higher current density at recessed parts. An overflow chamber is fitted at the top of the container from which the electrolyte consisting mainly of chromic acid is returned by a pump through a heating or cooling device to the bottom of the container.