Home | Table of Contents | Contact CEI | Search |What's New
|
Electrosol Painting
By W.M. Zadorsky (zadorsky@hotmail.com)
1. Introduction
Electropainting is a method that uses high-voltage electric discharge to convert a paint
spray to what is called electro(aero)sol. Its particles then allow controlled deposition
on a surface resulting in a very little loss of paint.
The process conventionally uses high-voltage devices which are bulky, unsafe and
expensive.
The project is aimed at development and elaboration of a compact, safe and low-cost unit
for high-quality electrosol painting.
2. Project Description
2.1. Equipment
The unit includes a rotational sprayer and a high voltage supply. The voltage converter of
the HVS is so compact that it permits placing it near the sprayer head. This results in
improved safety and reduced cost, for no high voltage cables are needed.
2.1.2. High-Speed Sprayer VR-30
The sprayer is basically a high-speed air turbine with a sprayer head attached to its
shaft. For more reliable service, the shaft is supported on two-row bearings. The solvent
and the paint are fed to the head via a system of passages. An additional air passage is
provided that enables control over the jet shape.
Specifications of VR-30 Sprayer
Paint work material flow rate 50-900 cm3/min
Head rotational speed Max. 30,000 rpm
Life to failure at max. speed service Min. 2000 h
Air pressure 0.2-0.3 MPa
Overall dimensions 135 by 100 by 100 mm
Weight Max. 1.8 kg
2.1.2. Low-Speed Sprayer
For less demanding applications, a simpler sprayer NR-4 may be used. It operates at 4000
rpm.
2.1.3. High Voltage Supply
The device consists of a control block and a voltage converter connected to it with a
common cord. The control block supplies low voltage of desired value and form which is
then converted to a preset high voltage. The converter is placed near the sprayer.
The system offers following advantages:
A. Safety.
(1) No high-voltage cables are used, for the high voltage is generated in the immediate
neighborhood of the sprayer.
(2) For improved fire safety, a duplex spark suppression system is provided. It uses
current stabilization and also switches HVS off as the electrode approaches an earthed
component.
B. Optimum operation due to current stabilization which maintains the specific charge
quantity at a preset level.
C. Compactness, light weight and reliable design of the converter.
Specifications of Korona-120-2 Continuous-Mode High Voltage Supply
Output voltage Max. 120 kV
Voltage amplitude Max. 12 V
Discharge current Max. 150 (A
Converter dimensions 60 by 60 by 315 mm
Converter weight 1.2 kg
Control block dimensions 320 by 285 by 140 mm
Control block weight 4 kg
Cord length Max. 20 m
Control block input voltage AC 220V ( 10%, 50Hz
Input power Max. 15 VA
Average life to failure 2500 h
2.2. Performance
The paint loss may be reduced to 2 % under industrial conveyor conditions. This holds
especially well for mass-produced components featuring a low solid area, like grids,
frames etc. The entire surface can be painted with a sprayer located on one side.
The high-speed sprayer ensures very good finish due to fine size of paint droplets.
The electric charging device can be used for any type of sprayer.
3. Novelty
Some engineering solutions used in the development are patentable.
4. Marketing
In its current condition, an electropainting system including the Korona-120-2 high
voltage device and a sprayer of either VR-30 or NR-4 type is offered for sale.
The system components allow further improvement that can be carried out within project
framework.
5. Applications
Mechanical and repair shops. Machine building factories.
Home | Table of Contents | Contact CEI | Search |What's New
|
