US3959002A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing white furnace boats for firing ceramic articles and novel furnace boats
Assignee: Robert Bosch GmbH
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Filing: 1974-05-02
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Granted: 1976-05-25
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Expires: 1994-05-02
Abstract
Abstract A method for manufacturing white furnace boats which are used for firing ceramic articles at temperatures up to about 1700° C. The furnace boat is made from a mixture of between 45% and 55% of synthetic corundum having a particle size of between 1 and 2 mm, between 25% and 35% of synthetic corundum having a particle size of between 0.1 and 0.2 mm, between 5% and 20% of kaolin having a particle size of 99% under 0.06 mm and 0.1% over 0.06 mm, and between 5% and 10% of quartz having a particle size of between 0.1 and 2 mm. The product white furnace boats are α-Al 2 O 3 in the amount of 60% to 70%, mullite in the amount of 20% to 30%, and a glass phase together with some cristobalite in the amount of 5% to 10%.
Inventors
- 👤 Friedrich J. Esper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:55
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/101; C04B33/00; C04B33/02; C04B33/13
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
A method for manufacturing iron-free refractory ceramic articles comprising admixing until a homogeneous mixture is obtained a. between 45% and 55% of synthetic corundum having a particle size of between 1 and 2 mm; b. between 25% and 35% of synthetic corundum having a particle size of from between 0.1 and 0.2 mm; c. between 5% and 20% of kaolin having a particle size of 99.9% under 0.06 mm and 0.1% over 0.06 mm; and d. between 5% and 10% of quartz having a particle size of between 0.1 and 2 mm; and then firing said homogeneous mixture at an elevated temperature to form a white furnace boat.
Claim 2
Independent Claim
108 words
A method for manufacturing iron-free refractory ceramic articles comprising admixing until a homogeneous mixture is obtained a. between 45% and 55% of synthetic corundum having a particle size of between 1 and 2 mm; b. between 25% and 35% of synthetic corundum having a particle size of from between 0.1 and 0.2 mm; c. between 5% and 20% of kaolin having a particle size of 99.9% under 0.06 mm and 0.1% over 0.06 mm; and d. between 5% and 10% of quartz having a particle size of between 0.1 and 2 mm; and then firing said homogeneous mixture at an elevated temperature to form a white furnace boat.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said homogeneous mixture is fired in the temperature range of 1600 to 1700° C.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein said homogeneous mixture is of a dough-like consistency and contains water and a wetting agent and a binder.
Claim 5
Dependent Claim
24 words
The method of claim 3 wherein said dough-like homogeneous mass is formed into the shape of a furnace boat and then dried and fired.
Claim 6
Dependent Claim
115 words
The method of claim 4 wherein 52% of synthetic corundum having a particle size of 1 to 2 mm; 28% of synthetic corundum having a particle size of from 0.1 to 0.2 mm; 13.5% of kaolin having a particle size of 99.9% below 0.06 mm and 0.1% over 0.06 mm; and 6.5% quartz having the following particle size distribution 1.7% over 1 mm
0.6% 0.5 to 1.0 mm
0.5% 0.3 to 0.5 mm
0.7% 0.3 to 0.4 mm
1.2% 0.2 to 0.3 mm
1.8% 0.1 to 0.2 mm are admixed with about 10% of water and 0.5 to 5 percent of aluminum-monophosphate and 0.5 to 5 percent of alkali-lignin sulfonate to form said homogeneous mass.
Claim 7
Dependent Claim
24 words
The method of claim 1 wherein said dough-like homogeneous mass is formed into the shape of a furnace boat and then dried and fired.
Claim 8
Dependent Claim
24 words
The method of claim 2 wherein said dough-like homogeneous mass is formed into the shape of a furnace boat and then dried and fired.
Claim 9
Dependent Claim
84 words
An iron-free refractory white furnace boat produced in accordance with the process of claim 1 having good service characteristics when serving as furnace boats for sintering other ceramic articles, said iron-free refractory white furnace boat consisting essentially of between about 60% and 70% α-Al 2 O 3 , between about 20% and 30% mullite, between about 5% and 10% of glass phase containing cristobalite, and up to about 0.6% of impurities; and having a density of between about 2.6 and 2.8 g/cm 2 .
Claim 10
Dependent Claim
55 words
The furnace boat of claim 8 consisting essentially of about 87% Al 2 O 3 and about 13% SiO 2 , and containing between about 0.2% and 0.4% of impurities, wherein the amounts of Al 2 O 3 and SiO 2 are present in said α Al 2 O 3 , mullite and glass phase.
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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) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |