Modern principles of sheet-forming systems like Hybrid Formers and Gap Formers could be realized only because new components and materials with specific properties are available today.
With the examples of a dewatering and forming shoe with curved formation length and a two slotted felt suction cover, the selection criterious necessary for ceramic covers in modern Paper Machines will be explained.
When producing Fine Papers with heavy filler load the wear resistancy of modern ceramic materials can be an even more important selection criterion than the heat resistancy factor.
Studying the Tribosystem involving the factors fabric, ceramic cover and fillers more closely, we find the fabric wear and the drive load consumption of a sheet former mainly determined by the filler and the ceramic material in use.
When using filler materials, considered from a mineralogical point of view, consisting of hard and adrasive substances like ground calcium carbonate, fabric and cover wear is determined by the abrasiveness of the filler material and the surface characteristic of the ceramic material.
We can prove, that fabric and cover wear are determined more by the particle size and particle size distribution than by the quantity of fillers in use. The percentage of pores, the diameter of pores and the pore distribution in the caramic cover's suface play a dominating role in the wearing mechanism, too.
With ceramic cover materials it is now possible to measure the surface porosity with an interactive picture analysis system. This makes it possible to give exact statements about pore nombers, pore sizes and pore size distribution. Today this IBAS surface porosity measurement is an important supplement to the previously known measuring methods with which the surface of ceramic covers are described and defined. Now it is possible to give clear statements about the diameter relation of filler particle and cover pore.
The manufacturers of fabrics, fillers and ceramic covers now can play an active role in optimizing their products further to assist the paper makers' efforts in achieving a higher productivity in modern sheet formers.
抄録全体を表示