High Tech Separating Solution for Overspray
in Car Paint Coating
E-Scrub revolutionises automobile painting
Colour is one of the most important means of giving expression to our lively and creative nature. This is also applicable to our car. The colour of one’s vehicle always reveals something about the nature of the owner – and the corresponding underlying sentiment of society.
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Source/Quelle: Eisenmann AG
With E-Scrub, Eisenmann AG has developed an electrostatic separation system for wet paint application systems as a highly efficient alternative to traditional separation principles.
At the beginning of the 1990’s, most of our roads were populated by bright and striking colours. This was then followed by silver/grey and black. The most recent trend has been white, standing for purity and honesty. The latest trend is brown and matt paint. Colours are expected to become brighter in the course of the next few years, according to trend researchers, and the 1970’s retro look might put in a reappearance.
Irrespective of the colour used, all cars have to be painted. And in general, this is carried out in car coating lines at one of the two leading manufacturers of paintwork installations in the world. Eisenmann, with headquarters in Böblingen and Holzgerlingen as well as branches around the globe, is one of these two leading manufacturers. With E-Scrub, this leading international system provider has now developed a separating process which is revolutionising the application of car paintwork.
Electrostatic separation system instead of a wall of water
In traditional solutions, cars have been painted by spraying the “overspray” – the paint which is sprayed past the bodywork – and is deposited against a wall of water. This water is subjected to chemical coagulation and disbanding and is treated with filters or decanters in a recycling arrangement. The high energy input is a major handicap of this method. Depending on the paint application process and the shape of the vehicle, the overspray accounts for approximately 25 to 35 percent of all the paint. This is a considerable quantity. With E-Scrub, Eisenmann AG has developed an electrostatic separation system for wet paint application systems as a highly efficient alternative to traditional separation principles. In this way, it is possible to reduce CO2 emissions by lowering the energy requirement. Water consumption is also reduced, by up to 86 percent, and chemical consumption is reduced by approximately 75 percent. However, the main savings are achieved in terms of energy consumption, which is reduced by up to 75 percent. Particulate emissions can also be reduced by a factor of 35.
These decanters reliably ensure that the separating agent remains at a stable level, is recycled and can be sprayed onto the separating plates – for the next car.
Source/Quelle: Eisenmann AG
The process in detail
The electrostatic dry overspray separating system is located below a grid in the spray booth. The separating modules consist of high voltage wires and separating plates, which are coated with a thin film of separating agent. The high voltage wires ionise the air molecules in the surrounding air. The paint particles take on this charge as they pass by, and are then attracted by the earthed separating plate. This is where the paint particles are bound and disbanded by the separating agent. The separating agent together with the overspray then flows into a buffer tank.
Centrifugal separation solution for the valuable separating liquid
And this is precisely the point at which the technology of GEA Westfalia Separator Group is used. This is because a process of separating the valuable and the separating liquid from the paint particles requires a high tech separating solution. Eisenmann therefore approached GEA Westfalia Separator Group and agreed to a long-term collaboration for developing the process. Firstly, GEA Westfalia Separator Group designed a specially modified decanter - UCE 205 - at the end of 2009, with a capacity of one cubic meter per hour for the laboratory-scale and demonstration installation at Eisenmann in Böblingen. Eisenmann was extremely satisfied.
After the installation had been successfully commissioned, the manufacturer received its first major order in 2010 for using the E-Scrub at a well-known German car maker, in which two identical UCE 205 decanters were integrated. These decanters reliably ensure that the separating agent remains at a stable level, is recycled and can be sprayed onto the separating plates – for the next car. The dry overspray which is discharged as a solid from the decanter can be disposed of properly. Accordingly, the combination of E-Scrub and the decanters means that, in the future, vehicles can be painted in a much more energy-efficient manner and thus in a much more environmentally friendly way, and at the same time using a more efficient method – using the brightest colours.
UCE 205 decanter