Airless: efficiency in the application

By: Vanesa Restrepo

The era when architectural and commercial applications were made only with brushes and rudimentary rollers was long gone. The rapid growth of cities and their modernization forced the industry to look for new solutions to have more applications on different surfaces, in a shorter time and with the best possible efficiency.

Initially, the spraying and painting application system was developed using systems developed based on air pressure. The operation of this equipment allows pressure to be applied to the paint by means of a pump that pushes it directly towards a gun. The latter fulfills a spraying function, making a sprinkler of the coating on the treated surface.

However, the air mixed with the paint particles forces to exert great pressures to push the material. By increasing this pressure, the rebound of the paint droplets increases, creating greater waste and problems in the areas adjacent to the application surface. As stated by James Valencia, in his document "Systems for the application of paint", excellent quality can be achieved with this process "but requires a higher pressure, in the range of 50-75 psi. This higher pressure causes an excessive 'bounce' or turbulence of the material, decreasing the efficiency to 15 - 30%" However, the author clarifies that this type of applications provide an excellent finish.

New solutions
The solution to these problems was the elimination of the harmful element: air. This is how airless equipment was born, systems that carry the material to the gun by pressure, generating the atomization of it.

According to Valencia "the fluid pressures in this system are in a range between 1,500 to 3,000 psi. The quality of atomizing without air can be classified between acceptable and good with an efficiency between 30 - 40%. The increase in efficiency is due to the fact that there is no presence of air in the paint giving a low rebound of material".

These systems are on the market in presentations ranging from electric pumps, to gas and pneumatic pumps. In this edition of INPRA LATINA we will analyze the advantages of these systems and see the technical characteristics of some of the main models of electric airless equipment, available in the Latin American market.

To that is added that in the airless system the paint bounces less, which implies a greater transfer of paint to the surface and a consequent saving in paint. As we already mentioned, the efficiency against the air spray system reaches 40%, thanks to the fact that thicker layers of paint can also be obtained and higher viscosity materials applied.

"The airless system is better suited to the high speeds on the production line. You can apply more paint with greater thickness, obtain good penetration in hidden areas of the pieces or the surface on which the application will be made. Additionally, airless painting will take five times less time than traditional brush applications, thanks to the fact that extensions or roller systems with self-feeding can be adapted," explains Valencia.

It should be noted that applications with airless equipment are easy to run on all kinds of surfaces: brick, block, stucco steel, wood and walls with reasonable times and cost efficiency.

The offer
In the Latin American market you can find different types of airless equipment, as well as guns and hoses to obtain better performance. The product lines are divided between electric airless sprinklers, such as those we will discuss in Table 2, pneumatic or gas-based.

The energy source can mean a higher or lower cost, depending on the application for which it is used. That is, if the person or company that acquires the equipment carries out work outdoors, in remote areas or in industrial fields, it should probably use a gas equipment, since it is not certain that it will find a source of electricity near the site of the work.

In the case of the equipment we deal with today, the electrical ones, it should be mentioned that they have the best performance and cost/benefit ratio in architectural or commercial applications, especially in urban areas. The reason is simple: the cost of energy in most Latin American countries is lower than that of fuels and gas.

Below we present the details of four references of electric airless equipment marketed in the region. Most of them can be purchased through distributors in different countries.