Filter medium for filtering molten metals
AssigneeSwiss Aluminium Ltd.
InventorsWolfhart Rieger, Lugwig Gauckler, Konrad Kampfer, Albert Mauer, Marco Dellapina, Volker Nobbe
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Abstract
Filter medium in the form of a stable body made of ceramic material and employed for filtering molten metals. The filter medium is made up of at least two effective filter layers such that a relatively thick layer of large pore diameter lies on a relatively thin layer of small pore diameter. This arrangement aims at attaining the maximum possible wetting of the interior of the filter medium.
Claims9
A filter medium in the form of a stable body of ceramic material for filtering molten metal comprising at least a first filtering layer A and a second filtering layer B arranged one after the other in the direction of filtration, said at least first filtering layer A having a thickness d.sub.A of between 9-91 mm, porosity f.sub.A of between 0.25-0.8 and pore diameter .lambda..sub.A of between 0.5-2 mm wherein the parameter H.sub.SA of layer A which is proportional to the filtering resistance of layer A is equal to ##EQU4## and has values of between 28-14,560 cm.sup.-1, said at least second filtering layer B having a thickness d.sub.B of between 1-33 mm, porosity f.sub.B of between 0.25-0.5 and pore diameter .lambda..sub.B of between 0.2-1 mm wherein the parameter H.sub.SB of layer B which is proportional to the filtering resistance of layer B is equal to ##EQU5## and has values of between 20-33,000 cm.sup.-1, and wherein the ratio of thickness d.sub.A to thickness d.sub.B lies between 9:1 and 3:1, and the ratio of the numerical values of parameters H.sub.SA and H.sub.SB lies between 1:1.2 and 1:30.
Dependencies are inferred from the claim text.