US4525462A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dark blue dyed furnace sight glass with high infrared absorption
Assignee: Deutsche Spezialglas AG
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Filing: 1983-05-26
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Granted: 1985-06-25
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Expires: 2003-05-26
Abstract
Abstract Dark blue dyed furnace sight glass of soda-lime-silica further containing carbon and oxides of iron and cobalt with substantially no infrared transmission and which sight glass affords a view of details in the melting operation. Other ingredients may include K 2 O, MgO, Al 2 O 3 or ZrO 2 .
Inventors
- 👤 Werner Behr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:22
CPC Classifications
F; F27; F27D; F27D21/00; F27D21/02; C; C03; C03C; C03C1/00; C03C1/10; C03C3/00; C03C3/04; C03C3/076; C03C3/089; C03C3/091; C03C3/093; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/904; Y10S501/905
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
140 words
Dark blue dyed furnace sight glass with a high infrared absorption, characterized by the fact that it has been melted from an amount of basic glass containing iron compounds to which a carbon containing reducing agent is added, its blue coloring being due to at least one cobalt compound and its iron, carbon and cobalt contents being such that the absorption characteristics of the glass in the visible spectral area provide distinctly visible details at slight differences in temperature between different portions of a radiating body and in the infrared spectral area provide substantially no transmittance of wavelengths of about 800 nanometers, the glass characterized by the following composition (in percent by weight): ______________________________________
65-72 SiO.sub.2
0-3 Al.sub.2 O.sub.3
0-3 ZrO.sub.2
12-16 Na.sub.2 O
0-5 K.sub.2 O
2.5-10 CaO
0-4 MgO
2.2-4.9 Fe.sub.3 O.sub.4
0.1-0.35 CoO
0.2-0.5 C .
______________________________________
Claim 2
Dependent Claim
140 words
Dark blue dyed furnace sight glass with a high infrared absorption, characterized by the fact that it has been melted from an amount of basic glass containing iron compounds to which a carbon containing reducing agent is added, its blue coloring being due to at least one cobalt compound and its iron, carbon and cobalt contents being such that the absorption characteristics of the glass in the visible spectral area provide distinctly visible details at slight differences in temperature between different portions of a radiating body and in the infrared spectral area provide substantially no transmittance of wavelengths of about 800 nanometers, the glass characterized by the following composition (in percent by weight): ______________________________________
65-72 SiO.sub.2
0-3 Al.sub.2 O.sub.3
0-3 ZrO.sub.2
12-16 Na.sub.2 O
0-5 K.sub.2 O
2.5-10 CaO
0-4 MgO
2.2-4.9 Fe.sub.3 O.sub.4
0.1-0.35 CoO
0.2-0.5 C .
______________________________________
Claim 3
Dependent Claim
27 words
The sight glass of claim 1 in which said magnesium oxide is present in said composition in an amount in the range of 2.9-4 percent by weight.
Claim 4
Dependent Claim
20 words
The sight glass of claim 1 in which said reducing agent consists essentially of carbon or a carbon containing compound.
Claim 5
Dependent Claim
23 words
The sight glass of claim 1 in which said glass composition is sufficiently devitrification-resistant to be produced according to the Fourcault drawing process.
References Cited (Backward Citations)
US2034994A
Cited
FR1389087A
Cited
US2755212A
Cited
GB1163482A
Cited
US3378431A
Cited
JPS5325615A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |