Electrostatic spray coating with variable voltage - and numerous electrodes, to produce highly uniform coating at wide ranging distances

摘要

Electrostatic spraying of a coating comprising powder, granules or liq. onto an article consists of applying a lower charge to those particles which have only a short distance to travel to reach the article than the charge applied to those particles which have a longer distance to travel. Pref. the H.T. voltage used is modified periodically, esp. with a frequency of 10-100 (15-25) per min. A much greater uniformity of coating thickness is obtd., in particular where depressions occur in the article to be coated. It is also possible to spray nylon powder.