Filters made from chemical binders and microspheres
This invention relates to filters made from a refractory material, preferably an insulating material, and chemical binder. The filters are used in the foundry industry to filter molten metal. The invention also relates to a process for preparing the filters.
1 . A filter comprising a refractory material bonded together with an effective bonding amount of a foundry binder.
2 . The filter of claim 1 wherein the refractory material is an insulating material that comprises ceramic microspheres.
3 . The filter of claim 2 which is shaped such that it has an entrance means and exit means.
4 . The filter of claim 3 wherein the exit means is flat.
5 . The filter of claim 4 wherein the exit means is concave.
6 . The filter of claim 5 wherein the exit means is convex.
7 . A process for preparing a filter comprising:
(a) forming a mix comprising a refractory material and an effective bonding amount of a foundry binder,
(b) shaping said mix to form a shape, such that shape contains openings through which molten metal can pass; and
(c) curing said shape.
8 . The process of claim 7 wherein the process is a cold-box process comprising:
(a) forming a mix comprising a refractory material and an effective bonding amount of a foundry binder,
(b) shaping said mix to form a shape, such that shape contains openings through which molten metal can pass; and
(c) curing said shape with a gaseous curing catalyst.
9 . The process of claim 8 wherein the refractory is an insulating material comprises ceramic microspheres.
10 . The process of claim 9 wherein the binder is a phenolic urethane binder and the catalyst is triethylamine.
11 . A no-bake process for preparing a filter comprising:
(a) forming a mix comprising a refractory material, an effective bonding amount of a foundry binder, and a liquid curing catalyst; and
(b) shaping said mix to form a shape, such that shape contains openings through which molten metal can pass.
12 . The process of claim 11 wherein the refractory material is an insulating material comprising ceramic microspheres.
13 . The process of claim 12 wherein the binder is a phenolic urethane binder and the catalyst is a liquid tertiary amine.
14 . A filter prepared by the process of claim 6 , 7 , 8 , 9 , 10 , 11 , 12 , or 13 .
15 . A process for casting a metal part which comprises:
(a) inserting the filter of claim 1 , 2 , 3 , 4 , 5 , or 6 into a pouring cup or directly in a sprue of a mold assembly;
(b) manufacturing the filter as an integral part of the pouring cup or mold assembly
(b) pouring metal, while in the liquid state, through said filter;
(c) allowing said metal to cool and solidify; and
(d) then separating the cast metal part from the casting assembly.