Pneumatic spraying without heating of paint material
Pneumatic spraying without heating is used to apply paints, enamels and other coatings. Paintwork materials based on almost all kinds of film formers.
Disadvantages of the method:
- fairly high solvent costs;
- considerable expenses of paintwork materials for fogging (from 20 to 40%, and sometimes even more);
- it is necessary to paint in special chambers with good ventilation and air cleaning system;
- Expensive operation of paint spraying booths.
The components of the pneumatic spraying unit: oil-water separator, centralized compressed air line (or mobile, portable compressor), spray gun (paint sprayer), hoses for paint and compressed air supply, paint hopper with mixing device and reducer.
In order to obtain compressed air, use portable compressors SO-62M, SO-45A, SO-7A, etc.
At large volumes of painting often use compressors CO-7A and CO-62M, as they are mobile vertical, working at a high pressure (6 kgf/cm2), have a fairly high rate of output (30 m3 / h). Their safety valve is adjusted on excess pressure of 8 kgf/cm2. Receiver capacity is 22 and 24 liters, and engine power is 3.0 and 4.0 kW, respectively. The weight of SO-7A portable unit is 140 kg, and SO-62M - 165 kg.
CO-45A compressor is portable, so it is more mobile. Maximum pressure is two times less than that of its vertical congeners, and productivity is 10 times less.
The power of the electric motor of CO-45A compressor is 0,15 kW. There is no receiver. Relief valve is adjusted to an excess pressure of 3.1 kgf/cm2. And the weight is only 21 kg. The indisputable advantage of the SO-45A diaphragm compressor is that it can act as a vacuum-pump to create a vacuum (about 25 mm Hg).
Two-cylinder single-stage simple-acting piston compressors with air-cooled cylinders can create an air working pressure of about 4 to 7 kgf/cm2.
One-stage portable diaphragm compressor CO-45A is used for sprayers painting material that operate at low air pressure (up to 3 kgf/cm2). In most cases these are airbrushes.
High quality compressor units are produced by VZSOM (Vilnius plant of construction and finishing machines).
Oil sprayers can be suspended (SO-15A or C-418A) or floor (C-732) designed by VZSOM.
In industrial environments are often used paint spraying tanks type SO-13, SO-12 and SO-42 (VZSOM).
SO-13 unit (paint-spraying tank) is a completely sealed vessel with a lid. It is on the lid and mounted fittings of the tank. In order to reduce air pressure on the paint, a reducer is used. From the reducer, one part of the air goes to the paint sprayer and the other part (where the pressure is reduced) goes to the paint tank and displaces the paint to the paint sprayer. If there is excess pressure in the tank, it can be relieved manually by turning the pressure relief valve screw. If, for some reason, the person working on the unit has not released the overpressure, it is released independently when the pressure reaches 4.5 kgf/cm2. Self-relieving pressure is carried out by means of a safety valve. This provides additional safety of work and safety of the product.
VZSOM produces a large number of different units and devices. One of them is a pneumatic turbine C-417A. It is necessary to transmit rotary motion to the agitator.