SPRAY TECHNOLOGY EXPLAINED
The key differences between the different types of spray atomisation are explained below. This will give you an idea of what kind of equipment you might need for your application:
1. AIR-ATOMISING SPRAY
Air-atomising spray is either:
HVLP (High Volume Low Pressure)
A large volume of air is used at the Air Cap.
This type of spray uses the lowest pressure
(up to 0.7 bar);
Compressed air is used at the Air Cap,
at a pressure of up to 7 bar.
A needle and nozzle regulates material flow.
HVLP has a higher transfer efficiency rate but lower application speed than conventional air-spray. However, most of our air-atomising spray guns are now available with 'transfer efficiency control' (TEC), or 'compliant' technology – this allows higher transfer efficiency with better application speeds.
2. AIRLESS SPRAY
Airless spray uses only high pressure for atomisation; no air is introduced into the system. An airless tip is used, which defines flow, angle and finish.
3. AIR-ASSISTED AIRLESS SPRAY
With air-assisted airless spraying, a relatively small quantity of air is introduced into the fluid fan to improve atomisation in addition to the fluid being atomised at high pressure through an airless tip.
4. ELECTROSTATIC SPRAY
This method of spraying involves electrostatically charging the fluid particles, which are then electrostatically drawn to a conductive surface. This considerably improves transfer efficiency. This method can only be used in conjunction with the air-atomising spray or air-assisted airless technology.
All of our spray equipment complies with international environmental legislation.
Transfer efficiency is a measure of the amount of material that is actually applied to the sprayed surface, taking material losses or 'overspray' into consideration.
This graph shows a comparison of the different spraying methods, and their relative transfer efficiency:
This graph demonstrates the application speed for each method against transfer efficiency:
As indicated, where transfer efficiency may be high, application speed can be low.