US3930820A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Strengthening sheet glass by ion exchange
Assignee: ASG Industries Inc
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Filing: 1974-06-11
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Granted: 1976-01-06
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Expires: 1994-06-11
Abstract
Abstract By the addition of a small quantity of potassium chloride or arsenous sulfide to commercial grades of molten potassium nitrate, the potassium nitrate may be activated or purified sufficiently to produce strengthened glass by ion exchange equal to glass strengthened by use of highly purified laboratory reagent grades of potassium nitrate.
Inventors
- 👤 william C. Cooke
- 👤 Albert H. Agett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:53
CPC Classifications
C; C03; C03C; C03C21/00; C03C21/001; C03C21/002
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
60 words
In the method of activating a molten bath of chemically impure potassium nitrate for use in strengthening glass by an ion exchange method, the improvement comprising adding to said molten potassium nitrate bath, an effective amount of potassium chloride or arsenous sulfide to remove substantially all of the calcium and magnesium impurities as compounds that are insoluble in potassium nitrate.
Claim 2
Dependent Claim
60 words
In the method of activating a molten bath of chemically impure potassium nitrate for use in strengthening glass by an ion exchange method, the improvement comprising adding to said molten potassium nitrate bath, an effective amount of potassium chloride or arsenous sulfide to remove substantially all of the calcium and magnesium impurities as compounds that are insoluble in potassium nitrate.
Claim 3
Dependent Claim
31 words
The method of claim 1 in which the effective amount of arsenous sulfide added to the chemically impure potassium nitrate bath is at least o.4% by weight of the potassium nitrate.
Claim 4
Dependent Claim
31 words
The method of claim 1 in which the effective amount of potassium chloride added to the chemically impure potassium nitrate bath is at least 0.6% by weight of the potassium nitrate.
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) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |