Development of a mobile plasma cleaning method for facades
IGF 15271 N
Soiled façades are cleaned currently with blasting processes using water or mixtures of water, air and solid blasting agents (e.g. sand, glass beads or calcium carbonate). An alternative to the mentioned cleaning procedures is offered by the plasma technology. Typical façades materials like clinker, sandstone, stoneware, marble, granite, anodized aluminium and stainless steel can be cleaned with cold atmospheric pressure plasma, as shown in the finalized research project. Herewith was developed a mobile water- and chemical free cleaning method which has been proved to be also material protective.
As ubiquitous soils were used graffiti (acrylic and synthetic resin paint) and artificial atmospheric soils. After soiling the samples were exposed 30 days to an artificial weathering procedure consisting of alternating UV-irradiation and thawing steps.
In order to achieve a high soil removal by means of plasma, different process gases, like compressed air, argon and nitrogen, were considered and different plasma parameters, like nozzle geometry, distance nozzle to surface and number of treatments, were varied.
An effective removal (up to 100 %) of acrylic and synthetic resin paints (black, green and red), as well as of algae and fungi was achieved by using a highly energetic air plasma beam under special parameter settings. White and silver acrylic paints instead could be removed to a much lower extend (max. 70 %). Neither abrasion nor thermal damage of the analysed façade materials could be detected. During the plasma treatment were reached relatively low surface temperatures depending on the type of material considered. Thus were measured 60 to 80°C for mineral, respectively 70 to 115 °C for metallic substrates.
The developed plasma cleaning method was evaluated in practice by comparison with conventional cleaning methods, including cleaning agents. Contrary to the water high pressure blasting method, all typical soils (like paints, algae, fungi) could be removed by air plasma even from very rough façade materials, like finery and red clinker, chemical- and residue-free.
The IGF-project 15271 N of the research association Europäische Forschungsgemeinschaft Reinigungs- und Hygienetechnologie e.V., Campus Fichtenhain 11, D-47807 Krefeld, was supported via the AiF within the funding programme „Industrielle Gemeinschaftsforschung und –entwicklung (IGF)“ by the Federal Ministry of Economic Affairs and Technology (BMWi) due to a decision of the German Parliament..
The research report is available on request from FRT.