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US3784387A
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Glass compositions of low inherent radioactivity
Assignee: Schott AG
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Filing: 1971-03-04
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Granted: 1974-01-08
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Expires: 1991-03-04
Abstract
Abstract Borosilicate glass of low inherent radioactivity, free of potassium oxide.
Inventors
- 👤 W Sack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:42
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/076; C03C3/089; C03C3/091; C03C3/093
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
6 words
Glass tubing according to claim 1.
Claim 2
Dependent Claim
6 words
Glass container according to claim 1.
Claim 3
Dependent Claim
26 words
Glass according to claim 1, consisting essentially of: SiO2 - 65.5% B2O3 - 12.0% Al2O3 - 5.0% Na2O - 6.5% ZnO - 8.0% BaO - 3.0%
Claim 4
Dependent Claim
11 words
Glass according to claim 1, said BaO+CaO content being entirely BaO.
Claim 5
Dependent Claim
13 words
Glass according to claim 1, essentially free of Fe2O3, Cr2O3, TiO2 and CeO2.
Claim 6
Dependent Claim
80 words
Method of producing glass having radioactivity of less than 0.4 pulses per minute as determined with a Beta -anti-coincidental counter, which comprises forming a melt of the following composition in weight percent on an oxide basis: SiO2 - 63-68% B2O3 - 10-13% Al2O3 - 4-6% Na2O - 5.5-7.5% ZnO - 2-9% BaO+CaO - 2-9% ZnO+BaO+CaO - 11%, and including in the batch from which the melt is formed, in weight percent of said oxides, 0.05-0.15 wt.percent of a reducing agent.
Claim 7
Dependent Claim
25 words
Method of claim 7, said composition being: SiO2 - 65.5% B2O3 - 12.0% Al2O3 - 5.0% Na2O - 6.5% ZnO - 8.0% BaO - 3.0%
Claim 8
Dependent Claim
11 words
Method according to claim 7, said BaO+CaO content being entirely BaO.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |