Method and apparatus for electrostatic powder coating
US4377603A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1979 |
| Grant date | Mar 22, 1983 |
| Priority date | — |
| Expiry date | Nov 1, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C2218/31
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A workpiece which may be made of a highly electrically insulating material is held in a spaced opposing relationship with respect to a silent discharge plate electrode to which an a.c. voltage is applied. A d.c. voltage is applied across the workpiece and the silent discharge plate electrode to form a driving electric field therebetween. Powder particles suspended in air are charged in the same polarity as that of the silent discharge plate electrode and then injected into the region between the silent discharge plate electrode and the workpiece where the electric field drives the charged particles toward the workpiece to coat it. The a.c. voltage is sufficient to repel the electrode surface confronting the workpiece and to maintain the silent discharge at a reduced level and effectively precluding deposit of powder particles on the mentioned surface. An apparatus for the electrostatic coating is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.