Process and apparatus employing a stream of electrolytic liquid for examining the porosity of coated objects

Apparatus for testing the porosity of objects having coated surfaces which have been coated by being subject to electrocoating with a water-based enamel, which comprises:

• at least one source of measurement voltage having first and second terminals;
• means for generating an uninterrupted stream of electrolytic liquid composed of the water-based enamel or its permeate derived through ultrafiltration for directing said stream against the coated surfaces of the object;
• first means for electrically connecting the first terminal of the source of measurement voltage to the objects;
• second means for electrically connecting the second terminal of the source of measurement voltage to the stream;
• and
• means for measuring the current flowing from the first electrically connecting means through the stream of liquid and the coating to the second electrically connecting means to test the porosity of the coating.

Apparatus for electrocoating the interior surfaces of ferromagnetic hollow bodies having open ends and for testing the porosity of the coatings, which comprises:

• a plurality of spaced, electrically conductive carrier and guide rails upon which the bodies are received with their open ends facing downwardly;
• means for directing a stream of electrolytic liquid into the bodies from below the guide rails through the spaces therebetween;
• means for applying an electrocoating voltage to the rails and to the stream to coat the interior surface of each body;
• means located above the carrier and guide rails for magnetically lifting the bodies off of the rails;
• and
• means for applying a measurement voltage to the bodies and to the stream and for measuring the current flowing through the bodies and the stream to test the porosity of the coating applied to the bodies.