The Warsaw Voice » The Polish Science Voice » Monthly - November 3, 2015
Environmental protection
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Staying Eco-Friendly in a Body Shop
Two Polish engineers have come up with a new eco-friendly and economical method for painting car bodies and furniture that ensures heat recovery and an optimal temperature throughout the process.

Air exchange plays an important role when car bodies and furniture parts are painted. The method developed by the engineers—Piotr Nikończuk, Ph.D., and Prof. Bogusław Zakrzewski from the West Pomeranian University of Technology in the northwestern city of Szczecin—is based on applying paint coatings while ensuring an exchange of air and the recovery of waste heat. The invention is intended for car body shops, furniture plants and companies that manufacture wood products.

In Poland there are about 4,500 car paint shops, and there is a huge market for their work, which can benefit from the new method developed by the Szczecin engineers. In 2006-2008, the number of road accidents and collisions recorded by police in Poland ranged from 436,000 to 458,000 a year. The method is also expected to generate interest in the wood and furniture industry as well as other sectors where manufacturing processes include painting.

The engineers say most paint booths use three operating modes: spraying, drying and ventilating. In the painting mode, the air in the booth is constantly exchanged. It is collected from the outside and pre-treated using a coarse filter. It is then heated to 20-21 degrees Celsius and fed into the paint booth using a ceiling filter. The air containing paint mist is cleaned with a “paint stop” filter and then removed from the booth via a floor canal. In the drying mode, the chamber temperature is from 40 to 60 degrees Celsius. After the process is completed, the booth is ventilated. The air circulation is the same as in the spraying mode except that during the ventilation stage, the air supplied to the paint booth is not heated, the engineers say.

Normally, when hot air is removed from the paint booth and fresh air is collected, large amounts of heat are lost. To recover heat, many paint shops use special devices. Ventilation systems are often equipped with recuperators, or heat exchangers, that exchange the air in layers. The air ejected from the booth is not completely purified. The floor filter removes from 93 to 97 percent of the particles, according to the engineers. The rest is deposited and forms a residue that cannot be completely cleaned or is difficult to clean. This means that after about five years of intensive work, the recuperator becomes clogged up. In addition, the engineers explain, the paint residue formed in this way is an effective good insulator, which results in a continuous decrease in the efficiency of the heat recovery mechanism. The thermal conductivity of such a residue is comparable to that of mineral wool.

In the method invented by Nikończuk and Zakrzewski, no residue is deposited. Moreover, the heat exchanger can be easily cleaned. Unlike with other methods, it is also possible to quickly cool the painted details and the paint booth.

In addition to providing financial savings for automotive companies, the invention is environmentally friendly. The waste heat recovered can be used to heat the building housing the paint shop. This reduces fuel consumption and leads to lower carbon dioxide emissions.

The inventors have secured financial support from Poland’s National Center for Research and Development (NCBR) under its Patent Plus program to patent their invention throughout Europe. Their method has also received a positive preliminary evaluation in terms of its patentability.

The new painting method developed by the Szczecin engineers has made it into the finals of Dziennik Gazeta Prawna daily newspaper’s Eureka! DGP competition, which seeks to promote innovative Polish technologies.

Karolina Olszewska