Abstract: The present invention refers to the use of screens comprising at least two layers of different mesh or pore size in a cellulose powder preparation method as well as to said method, wherein grinding the cellulose pulp and sieving the obtained particles can be carried out on-line.

Abstract: A device for the treatment of a medical fluid including a permanently installed fluid treatment machine and a cassette with fluid-carrying channels as well as an elastic matt placed between these two items. The matt channels are recessed in the elastic matt and are provided with slits. Via the matt channels, an optimised vacuum distribution takes place and the slits serve the purpose of removing air between the cassette and the fluid treatment machine.