method and device for coating of metallgegenstaenden with pulverfoermigen materials

摘要

An electrostatic method of coating metal objects, e.g. steel pipes, with powdered resins, comprises grinding, heating to resin m.pt., electrostatic polarisation and the electrostatic discharge application of the powder; the grinding is followed, before the heating, by a high press. spray wash (esp. using water when handling steel pipes). The wash improves the surface finish and cancels the indeterminate charge caused by sand-blasting.