US4823359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Furnance having dense refractory oxide liner
Assignee: Saint Gobain Abrasives Inc
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Filing: 1987-11-25
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Granted: 1989-04-18
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Expires: 2007-11-25
Abstract
Abstract A refractory product is shown in the form of a dense sintered alumina-chromia, zirconia-alumina-silica, zirconia-alumina body, or zirconia-chromia-alumina having less than about 8% of homogeneously distributed closed porosity formed by sintering an intimate interdispersion of fine particles of alumina-chromia, zirconia-alumina-silica, zirconia-alumina, or zirconia-chromia-alumina.
Inventors
- 👤 Neil N. Ault
- 👤 Anthony K. Butkus
- 👤 Louis J. Trostel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:06
CPC Classifications
C; C03; C03B; C03B5/00; C03B5/16; C03B5/42; C03B5/43; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/101; C04B35/105; C04B35/106; C04B35/12; C04B35/66
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
74 words
A furnace for melting glass or gasifying coke and coal wherein the improvement comprises: a furnace lining consisting essentially of a sintered mixture of particulate oxides wherein the oxides are at least 98% pure, said lining is at least 92% of its theoretical density with the porosity present being non-continuous and uniformly distributed throughout the lining, and said mixture of oxides is made up of 10% to 90% alumina and 90% to 10% chromia.
Claim 2
Dependent Claim
74 words
A furnace for melting glass or gasifying coke and coal wherein the improvement comprises: a furnace lining consisting essentially of a sintered mixture of particulate oxides wherein the oxides are at least 98% pure, said lining is at least 92% of its theoretical density with the porosity present being non-continuous and uniformly distributed throughout the lining, and said mixture of oxides is made up of 10% to 90% alumina and 90% to 10% chromia.
Claim 3
Dependent Claim
26 words
The furnace of claim 1 wherein all of said particles of said oxides prior to sintering fall within a size range of 50 microns or less.
Claim 4
Dependent Claim
33 words
The furnace of claim 1 wherein said lining is constructed of bricks that have been hot pressed under a pressure of 1.5 tons per square inch at a temperature of about 1600° C.
Claim 5
Dependent Claim
66 words
The furnace of claim 1 wherein said mixture of oxides prior to sintering is formed by suspending said particles in a fluid and performing a high energy shearing action on the particles in the fluid suspension causing intimate and uniform dispersion of the particles throughout the fluid, and drying mixture so formed prior to the performance at said sintering step which is done by hot pressing.
Claim 6
Dependent Claim
23 words
The furnace of claim 1 wherein said mixture of oxides is rendered finely pulverized and intimately mixed by dry milling prior to sintering.
Claim 7
Dependent Claim
34 words
The furnace of claim 1 wherein said lining is constructed of bricks made by compressing said mixture of particulate oxides at room temperature followed by heat treating at about 1600° C. at atmospheric pressure.
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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) | 1992-04-17 | 1992-10-17 | 1993-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-17 | 1996-10-17 | 1997-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-17 | 2000-10-17 | 2001-04-18 | $7700.00 | Window Closed / Lapsed |