Georg Fischer Aktiengesellschaft

Hans G Trapp

Rolf Rietzscher

Franz Hofmann

Wolfgang Kaettlitz

Gerd Trinki

Jurgen Otto

A ceramic filter for filtering molten iron is disclosed. The ceramic filter is made from a high-melting ceramic material having an open-celled foam structure, a variable bulk density in different portions of the filter, and at least one afflux surface. In order to filter molten iron efficiently, the ratio of filter surface to filter volume should be in the range of about 0.0003 to 9 m.sup.2 /cm.sup.3, the specific filter resistance should be in the range of about 0.1 to 0.9 bar-cm at a flow rate of 5 m.sup.3 /hour, and the pressure loss .DELTA.p across the filter should depend on the specific resistance .rho., the filter length, and the surface area of the afflux plane F in accordance with the relationship: ##EQU1## A method for filtering molten iron using this ceramic filter is also disclosed. In this method, the ceramic filter is located near the point in the casting system where the molten iron has its greatest kinetic energy. The molten iron is first caused to flow tangentially by the afflux plane of the ceramic filter and then is deflected to create turbulence directly before the afflux plane of the filter.

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Schaffhausen, Switzerland

Hans G Trapp