New Technology in Spray Coating – Nitrotherm Spray

Technology is advancing rapidly each day, and keeping pace with it—or even shaping that change—has become critically important. In our time, it is clear that without technological support in virtually every medium and application, efficient processes and production would be impossible. As in every sector, one of the most important examples of changes in paints and coatings technology is the "Nitrotherm Spray Coating" technology, which is used by many brands worldwide and has been introduced to the market in our country by Latro Kimya. First, as can be understood from the name Nitrotherm, it is a technology whose name is derived from the abbreviation of the words Nitrogen (Azot) and Thermo (Isı). The system operates in summary as follows: Air coming from an existing compressor is instantaneously separated from oxygen and other gases through a patented membrane filter, leaving only nitrogen. The nitrogen, which comprises 78% of the air, begins to accumulate in a tank within the unit. The 21% oxygen and 1% other gases present in the air outside of nitrogen cannot pass through the filter due to molecular differences and are sent to the external environment through the exhaust section. The system retains only dry, moisture-free nitrogen gas, enabling its use in the coating system. Furthermore, temperature fluctuations caused by seasonal and day-night variations, which can never be stabilized, are made stable and controllable through the heated hose. This allows for application at constant temperature throughout all four seasons. In manual spray coating systems, spray guns have two inlets. One is the air inlet from the compressor, and the other is the paint inlet from the paint pump. These two lines are completely independent inputs. In normal systems, air exiting the compressor first passes through a dryer where moisture and oil removal takes place. The air then reaches the gun nozzle and exits through the air cap to contact the paint. However, compressors are always at a distance from the paint booth, and the dryer system is located immediately at the compressor outlet. Due to the length of the line and temperature fluctuations in the environment, air passing through the hose will cause moisture buildup. At the same time, since air always carries oxygen molecules, moisture formation is inevitable.

The atomization air that meets the paint at the gun nozzle will therefore be humid and the application quality, actually considered good, will be substandard. At precisely this point, Nitrotherm Spray comes into play, and pure, dry nitrogen gas, completely separated from moisture and oxygen, plays a significant role in improving surface quality. In laboratory trials, paint particles were measured to reach a fixed surface at 7 m/s with air, while measurements made using nitrogen gas showed that paint particles reached a fixed surface at 13 m/s.

For example, in an application using normal air, 6 bar atomization pressure is used with 4 bar and 400 ml/min paint flow rate. When surface thickness is measured, a thickness of 40 microns is obtained. Of course, because application is performed at high pressure and high flow rate, "overspray" and "bounce effect" occur, meaning paint is wasted. In the same application using Nitrotherm Spray, the 6 bar atomization pressure was reduced to 4.5 bar, and the paint flow rate was reduced from 4 bar 400 ml/min to 3 bar 300 ml/min. Subsequently, when surface thickness was measured, the desired 40 micron thickness and improved surface quality were achieved. Here, advantage was taken of the speed of nitrogen gas and its moisture-free nature. Since pressure and paint flow rate were reduced, overspray was significantly decreased, and thanks to nitrogen being a moisture-free and dry gas, a higher quality surface was obtained. The reduction in overspray—excessive spraying—means savings as well as a reduction in harmful solvent-containing gases released to the environment, lowering VOC values. Governments are particularly interested in this matter and take quite favorable approaches for incentive purposes. Through intensive field work and technical knowledge of our sales engineers, Nitrotherm Spray technology is providing significant benefits across many sectors in terms of savings, quality, and environmental protection. Discover this technology with Latro Kimya, which shapes technological advancement and takes your coating systems and production lines one step beyond today's technology. Gürkan Serttaş / Technical Sales Manager / Latro Kimya