Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
88 words
A honeycomb structure having a multiplicity of thin walls forming a plurality of open ended, substantially uniform, hollow cells extending between a pair of opposing outer surfaces of the structure and formed by an aggregation of grains, wide boundaries being present between grains, essentially all of said grains having average sizes, apart from the aggregation, of at least about 10 microns, the aggregation comprising at least 98% or more by weight A1 2 0 3 and alumina grain growth inhibitors in amounts insufficient to inhibit alumina grain growth.
Claim 2
Dependent Claim
88 words
A honeycomb structure having a multiplicity of thin walls forming a plurality of open ended, substantially uniform, hollow cells extending between a pair of opposing outer surfaces of the structure and formed by an aggregation of grains, wide boundaries being present between grains, essentially all of said grains having average sizes, apart from the aggregation, of at least about 10 microns, the aggregation comprising at least 98% or more by weight A1 2 0 3 and alumina grain growth inhibitors in amounts insufficient to inhibit alumina grain growth.
Claim 3
Dependent Claim
40 words
A honeycomb structure as claimed in claim 1 characterised in that the aggregation comprises at least 99.5% by weight A1 2 0 3 and a major proportion by weight of said grains have average sizes between 50 and 150 microns.
Claim 4
Dependent Claim
25 words
A honeycomb structure as claimed in claim 1 or claim 2 characterised in that aggregation has a total porosity of 10% or more bulk volume.
Claim 5
Dependent Claim
51 words
A honeycomb structure as claimed in any of claims 1 to 3 characterised in that the alumina is present in a form of reactive alumina particles essentially all of which have average sizes of 5 microns or less, further comprising a minor portion by weight of particles of a burned-out composition.
Claim 6
Dependent Claim
46 words
A honeycomb structure as claimed in claim 4 characterised in that the burned-out composition is provided in an amount sufficient to increase the total porosity of the thin walls to at least 10% bulk volume after sintering of the structure and combustion of the burned-out composition.
Claim 7
Dependent Claim
37 words
A honeycomb structure as claimed in claim 4 or claim 5 characterised in that the burned-out composition comprises artificial graphite in an amount of at least one part by weight graphite to 50 parts by weight alumina.
Claim 8
Dependent Claim
39 words
A honeycomb structure as claimed in claim 5 characterised in that it further comprises a minor portion by weight of reacted alumina aggregate, said reacted alumina aggregate containing at least 98% by weight A 1 2 0 3 .
Claim 9
Dependent Claim
30 words
A honeycomb structure as claimed in any of claims 4 to 7 characterised in that the reactive alumina particles contain at least 99.5% by weight A1 2 0 3 .
Claim 10
Independent Claim
61 words
A method of converting a honeycomb structure as claimed in any of claims 4 to 8 to a sintered molten metal filter, characterized in that the honeycomb is heated sufficiently to cause growth of the alumina particles into grains essentially all of which have average sizes of at least 10 microns, and until essentially all of said burned-out composition is combusted.
Claim 11
Dependent Claim
50 words
A method of filtering molten metal wherein a charge of molten metal is passed through the cells of a filter as claimed in claim 9 from one of the pair of opposing honeycomb outer surfaces whereby solid impurities in the molten metal charge are deposited on the one outer surface.