APPARATUS FOR TREATING THE INTERNAL SURFACE OF A TUBE BY ELECTRICAL GLOW DISCHARGE

摘要

To be able to treat the inside surface of metallic tubes by means of an electric glow discharge at pressures lower than heretofore in order to heat or coat such a surface, for example, an auxiliary electrode is positioned inside an article to be treated such as a tube extending close to the tube wall and parallel to the tube axis, with the auxiliary electrode and the tube being rotatable relative to each other. The apparatus and method are primarily for coating the inside of tubes.