In this paper we present an improved experimental method for studying initial dewatering process in papermaking. Effect of the dewatering pressure profile and the furnish type on the development of flow resistance and final solid content of the sheet is studied. Major difference to previous studies is the possibility to control the dewatering pressure profile during each filtration. The filtration process is monitored by measuring the pressure drop over the filtrated sheet,the velocity of the suspension surface and the final solid content. Finallythe sheet is analysed for its z-directional porosityusing X-Ray microtomography andfines distribution using a sheet splitting technique. Our results indicate that the sheet solid content after the initial dewatering depends on the pressure profile used during the filtration and that this dependency remains also after wet pressing. It is also shown that by using laboratory scale measurements presented here it is possible to find optimal dewatering conditions for different furnish types. Based on our results a novel model for development of sheet flow resistanceduring filtration is presented.
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