Molten metal filtration and distribution device and method for manufacturing the same

• US 6,270,717 B1
• Filed: 03/04/1998
• Issued: 08/07/2001
• Est. Priority Date: 03/04/1998
• Status: Expired due to Term

• Current Assignee: Les Produits Industriels de Haute Temperature Pyrotek Inc. (Pyrotek Incorporated)
• Original Assignee: Les Produits Industriels de Haute Temperature Pyrotek Inc. (Pyrotek Incorporated)
• Inventors: Tremblay, Sylvain P., Dault, Réjean, Legast, Pierre, Delvaux, Pierre
• Primary Examiner(s): KASTLER, SCOTT R
• Application Number:
  US09/034,337
• Time in Patent Office: 1,252 Days
• Field of Search: 222/606, 222/607, 222/594, 266/230, 266/227
• US Class Current: 266/230
• CPC Class Codes: B01D 2239/0457 Specific fire retardant or heat resistant properties apparatus incorporating such gas filtering material B01D46/0093
• CPC Class Codes: B01D 2239/0464 Impregnants
• CPC Class Codes: B01D 2239/0478 on a layer of the filter
• CPC Class Codes: B01D 2239/1291 Other parameters
• CPC Class Codes: B01D 39/086 of inorganic material
• CPC Class Codes: B22C 9/086 Filters

Abstract

There is provided a filtration and distribution device for a molten metal, which is in the form of a bag having parts made of a solid heat-resistant fabric and open areas made of an open weave heat-resistant fabric. At least some of the parts made of the solid heat-resistant fabric are replaced by rigid parts made of a moldable or thermo-formable composite consisting of an open weave heat-resistant fabric embedded into a matrix made of a heat-resistant inorganic material compatible with the open weave heat-resistant fabric. Preferably, the open weave heat-resistant fabric forming the open areas of the bag, is made of yarns that are rigidified and protected by application thereto of a heat-resistant coating. This coating is preferably made of a heat-resistant inorganic material applied by spraying or dipping after the yarns are weaved. The rigidification can be achieved naturally or by thermal treatment. There is also provided a distribution device for a molten metal, which comprises a hollow body provided with an outlet connectable to a molten metal feed pipe and at least one outlet through which the molten metal fed into the body may escape. This hollow body is made of the very same moldable and thermo-formable composite already mentioned hereinabove.

Claims

1. A filtration and distribution device for a molten metal, which is in the form of a bag having parts made of a solid heat-resistant fabric and open areas made of an open weave heat-resistant fabric, wherein at least some of said parts made of said solid heat-resistant fabric are replaced by rigid parts made of a moldable or thermo-formable composite consisting of an open weave heat-resistant fabric embedded into a matrix made of a heat-resistant inorganic material compatible with said open weave heat-resistant fabric and wherein the matrix is prepared from a moldable refractory composition in the form of a slurry which comprises:

from 8 to 25% by weight of an aqueous phosphoric acid solution having a concentration of phosphoric acid ranging from 40 to 85% by weight, said phosphoric acid having up to 50% of its primary acidic functions neutralized by reaction with vermiculite; and

from 75 to 92% by weight of a mixture containing wollastonite and an aqueous suspension containing from 20 to 40% by weight of colloidal silica in a weight ratio of said aqueous suspension to said wollastonite ranging from 0.5 to 1.2.

2. The device according to claim 1, wherein the bag is a combo bag comprising a main body, an outer shell, end patches, bottom and reinforcement patches and position tabs sewn altogether and wherein the parts of said combo bag that are replaced by said rigid parts are selected from the group consisting of said main body, outer shell, end patches, bottom and reinforcement patches and positioning tabs.

3. The device according to claim 2, wherein all the heat-resistant fabrics consist of glass fiber fabrics and, in the moldable refractory composition:

the aqueous phosphoric acid solution has a concentration of phosphoric acid equal to about 55% by weight;

the primary acidic functions of the phosphoric acid contained in the aqueous phosphoric acid solution are neutralized by reaction of 1 part by weight of vermiculite per 5 parts by weight of said aqueous phosphoric acid solution;

the aqueous suspension contains about 40% by weight of colloidal silica and about 60% by weight of water; and

the composition comprises from 10 to 20% by weight of said aqueous phosphoric acid solution partially neutralized with vermiculite.

4. The device according to claim 1, wherein the bag is a channel bag comprising a pan having a bottom portion and side portions and wherein the parts of said channel bag that are replaced by said rigid parts are parts of said bottom portion and side portions.

5. The device according to claim 4, wherein all the heat-resistant fabrics consist of glass fiber fabrics and, in the moldable refractory composition:

the aqueous phosphoric acid solution has a concentration of phosphoric acid equal to about 55% by weight;

the primary acidic functions of the phosphoric acid contained in the aqueous phosphoric acid solution are neutralized by reaction of 1 part by weight of vermiculite per 5 parts by weight of said aqueous phosphoric acid solution;

the aqueous suspension contains about 40% by weight of colloidal silica and about 60% by weight of water; and

the composition comprises from 10 to 20% by weight of said aqueous phosphoric acid solution partially neutralized with vermiculite.

7. The device according of claim 2, wherein the open weave heat-resistant fabrics forming the open areas of the bag is made of yarns that are rigidified and protected by a heat-resistant coating.

8. The device according to claim 7, wherein said heat-resistant coating is prepared from an aqueous suspension of wollastonite, colloidal silica and sugar having a sufficient viscosity to cover the fibers of the fabric while avoiding obturating the free spaces between said fibers, and wherein:

said suspension contains from 30 to 50% by weight of solids;

the colloidal silica and wollastonite are present in a weight ratio of colloidal silica to wollastonite ranging from 0.5 to 1.2; and

the sugar amounts to at least 25% by weight of the suspension and is present in a weight ratio of sugar to wollastonite+colloidal silica +sugar ranging from 0.55 to 1.0.

9. The device according of claim 4, wherein the open weave heat-resistant fabrics forming the open areas of the bag is made of yarns that are rigidified and protected by a heat-resistant coating.

10. The device according to claim 9, wherein said heat-resistant coating is prepared from an aqueous suspension of wollastonite, colloidal silica and sugar having a sufficient viscosity to cover the fibers of the fabric while avoiding obturating the free spaces between said fibers, and wherein:

said suspension contains from 30 to 50% by weight of solids;

the colloidal silica and wollastonite are present in a weight ratio of colloidal silica to wollastonite ranging from 0.5 to 1.2; and

the sugar amounts to at least 25% by weight of the suspension and is present in a weight ratio of sugar to wollastonite+colloidal silica +sugar ranging from 0.55 to 1.0.

6. A filtration and distribution device for a molten metal, which is in the form of a bag having parts made of a solid heat-resistant fabric and open areas made of an open weave heat-resistant fabric;

wherein at least some of said parts made of said solid heat-resistant fabric are replaced by rigid parts made of a moldable or thermo-formable composite consisting of an open weave heat-resistant fabric embedded into a matrix made of a heat-resistant inorganic material compatible with said open weave heat-resistant fabric;

wherein the open weave heat-resistant fabrics forming the open areas of the bag are made of yarns that are rigidified and protected by a heat-resistant coating;

wherein said heat-resistant coating is prepared from an aqueous suspension of wollastonite, colloidal silica and sugar having a sufficient viscosity to cover the fibers of the fabric while avoiding obturating the free spaces between said fibers, and wherein;

said suspension contains from 30 to 50% by weight of solids;

the colloidal silica and wollastonite are present in a weight ratio of colloidal silica to wollastonite ranging from 0.5 to 1.2; and

the sugar amounts to at least 25% by weight of the suspension and is present in a weight ratio of sugar to wollastonite+colloidal silica+sugar ranging from 0.55 to 1.0.

11. A distribution device for a molten metal, comprising a hollow body provided with an inlet connectable to a molten metal feed pipe and at least one outlet through which the molten metal fed into the hollow body may escape, wherein said hollow body is made of a moldable or thermo-formable composite consisting of an open weave heat-resistant fabric embedded into a matrix made of a heat-resistant inorganic material compatible with said open weave heat-resistant fabric and wherein said matrix is prepared from a moldable refractory composition in the form of a slurry which comprises:

from 8 to 25% by weight of an aqueous phosphoric acid solution having a concentration of phosphoric acid ranging from 40 to 85% by weight, said phosphoric acid having up to 50% of its primary acidic functions neutralized by reaction with vermiculite; and

from 75 to 92% by weight of a mixture containing wollastonite and an aqueous suspension containing from 20 to 40% by weight of colloidal silica in a weight ratio of said aqueous suspension to said wollastonite ranging from 0.5 to 1.2.

12. A distribution device for a molten metal comprising a hollow body provided with an inlet connectable to a molten metal feed pipe and at least one outlet through which the molten metal fed into the hollow body may escape;

wherein said hollow body is made of a moldable or thermo-formable composite consisting of an open weave heat-resistant fabric embedded into a matrix made of a heat-resistant inorganic material compatible with said open weave heat-resistant fabric;

wherein said at least one outlet is provided with a screen made of an open weave heat-resistant fabric having yarns that are rigidified and protected by a heat-resistant coating;

wherein said heat-resistant coating is prepared from an aqueous suspension of wollastonite, colloidal silica and sugar having a sufficient viscosity to cover the fibers of the fabric while avoiding obturating the free spaces between said fibers, and wherein;

said suspension contains from 30 to 50% by weight of solids;

the colloidal silica and wollastonite are present in a weight ratio of colloidal silica to wollastonite ranging from 0.5 to 1.2; and

the sugar amounts to at least 25% by weight of the suspension and is present in a weight ratio of sugar to wollastonite+colloidal silica+sugar ranging from 0.55 to 1.0.

13. The device of claim 12, wherein the matrix is prepared from a moldable refractory composition comprising:

8 to 25% by weight of an aqueous phosphoric acid solution having a concentration of phosphoric acid ranging from 40 to 85% by weight, said phosphoric acid having up to 50% of its primary acidic functions neutralized by reaction with vermiculite; and

75 to 92% by weight of a mixture containing wollastonite and an aqueous suspension containing from 20 to 40% by weight of colloidal silica in a weight ratio of said aqueous suspension to said wollastonite ranging from 0.5 to 1.2.

14. The device according to claim 12, wherein said hollow body comprises at least two of said at least one outlet, which are spaced apart.

15. The device of claim according to claim 13, wherein said hollow body comprises at least two of said at least one outlet, which are spaced apart.