Zusammenhang von Adhäsion und Reinigung von Mikropartikeln auf strukturierten Oberflächen

Adhesion of microparticles to surfaces is important for a number of industrial applications. Currently it is assumed that the adhesion between particles and surface needs to be resolved for a successful removal of unwanted particles in a cleaning process. It is supposed that the ability to remove particles from the surface correlates directly with the adhesion force measured by atomic force microscopy. Experiments are conducted with silicon‐ and stainless steel probes with various surface structures. An evaluation of the factors influencing adhesion and cleanability is performed.     

Reinigbarkeit von Oberflächen in der Lebensmittelindustrie durch Flüssigkeitsstrahlen

The influence of properties of product contact surfaces on cleanability is widely discussed in the food processing and pharmaceutical industry. In the present work stainless steel surfaces of different surface roughness, surface energy and electrokinetic properties were subject to organic soiling in order to study the influence of surface properties on cleanability. As food model test soils gelatinized starch and whey protein were chosen. The cleaning was realized by means of water jets from a flat fan nozzle.     

Berechnung der Haftung von Pulverpartikeln an strukturierten Oberflächen

The adhesion of powder particles on solid surfaces is influenced by many parameters. Among these influence factors the van‐der‐Waals‐forces and the humidity of the surrounding atmosphere play a dominant role. Since current models often neglect important parameters, in this paper different possibilities to calculate particle adhesion forces are presented. The calculated values allow the interpretation of adhesion force distribution and the assignment of adhesion forces to certain mechanisms.     

Untersuchung und Modellierung der Aufwirbelung von auf Oberflächen abgelagerten Partikelschichten

The paper describes an experimental method to create reproducible particle layers. These layers are to be resuspended. The resuspension process itself is monitored coincidentally with an optical method. A theoretical approach to the phenomena uses a balance of forces effecting at a characteristic particle of the layer to estimate a resuspension coefficient. This coefficient describes resuspension in the way mass transfer coefficients describe mass transfer phenomena in fluids.     

Abbildung von Oberflächen mit dem Rasterelektronenmikroskop unter besonderer Berücksichtigung der Abbauvorgänge bei der Bewitterung TiO2-pigmentierter Anstrichfilme

Studies on Surfaces Using Scanning Electron Microscope with Special Consideration of Degradation Processes During the Weathering of Paint Films Containing TiO₂-Pigment Fundamentals of scanning electron microscopy and the accessory instruments required for differentiating materials and for analysis are discussed. Using the scanning electron microscope a concept on the chalking of paint films containing TiO₂ as pigment was verified. It was found that in the course of degradation of the binding agent the particles of TiO₂ are not completely exposed, but instead, they adhere to the paint film via ?binder socket”?. The concepts derived from these studies permit the interpretation various phenomena that are observed in paint films subjected to weathering.     

Simulation der auf van der Waals Wechselwirkungen beruhenden Haftkräfte zwischen rauen Partikeln und glatten Wänden in gasförmiger Umgebung

A computer program is presented that can be used to calculate adhesion force distributions of irregularly shaped particles. Basis is the calculation of the single interactions between the involved atoms respectively molecules of the contact partners and overlapping these to a resultant whole interaction. The example of roughness shows that extremely bimodal distributions can arise for identical particles.