US4885263A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic foam filter and process for preparing same
Assignee: First Union National Bank of North Carolina
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Filing: 1987-03-23
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Granted: 1989-12-05
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Expires: 2007-03-23
Abstract
Abstract An improved ceramic foam filter for use in filtering molten metal prepared from a ceramic slurry containing silicon carbide and a colloidal silica binder. The filter has a solids content of at least 50% silicon carbide and at least 3% of silica.
Inventors
- 👤 Jerry W. Brockmeyer
- 👤 Leonard S. Aubrey
- 👤 James E. Dore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:36
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/20; B01D39/2068; B01D39/2093; B22; B22D; B22D11/00; B22D11/10; B22D11/11; B22D11/116; B22D11/119; C; C04; C04B; C04B38/00; C04B38/06; C04B38/0615; C22; C22B; C22B9/00; C22B9/02; C22B9/023; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
100 words
A process for preparing a ceramic foam filter for filtering molten metal which comprises: forming an aqueous slurry of a thixotropic ceramic composition including silicon carbide with a colloidal silica binder for imparting an improved level of thixotropy as a result of its colloidal nature, said composition having a solids content of at least 50% silicon carbide and at least 3% silica; providing a reticulated organic polymer foam; impregnating said foam with said aqueous slurry; drying and heating said impregnated polymeric foam to remove the organic components thereof; and firing at an elevated temperature to produce said ceramic foam filter.
Claim 2
Dependent Claim
100 words
A process for preparing a ceramic foam filter for filtering molten metal which comprises: forming an aqueous slurry of a thixotropic ceramic composition including silicon carbide with a colloidal silica binder for imparting an improved level of thixotropy as a result of its colloidal nature, said composition having a solids content of at least 50% silicon carbide and at least 3% silica; providing a reticulated organic polymer foam; impregnating said foam with said aqueous slurry; drying and heating said impregnated polymeric foam to remove the organic components thereof; and firing at an elevated temperature to produce said ceramic foam filter.
Claim 3
Dependent Claim
16 words
A process according to claim 1 wherein the silica solids content is from 3 to 15%.
Claim 4
Dependent Claim
20 words
A process according to claim 1 wherein the silicon carbide has a grain size of -b 100 mesh or smaller.
Claim 5
Dependent Claim
12 words
A process according to claim 1 wherein said ceramic composition includes alumina.
Claim 6
Dependent Claim
18 words
A process according to claim 4 wherein said alumina has a grain size of -325 mesh or smaller.
Claim 7
Dependent Claim
12 words
A process according to claim 1 wherein said slurry includes 10-50% water.
Claim 8
Dependent Claim
18 words
A process according to claim 1 wherein said heating stage is at a temperature up to 1250° F.
Claim 9
Dependent Claim
19 words
A process according to claim 1 wherein said polymer foam has a pore size of at least 3 ppi.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-04 | 1993-06-05 | 1993-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-04 | 1997-06-05 | 1997-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-04 | 2001-06-05 | 2001-12-05 | $7700.00 | Window Closed / Lapsed |