US3790475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Porous glass support material
Assignee: Corning Glass Works
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Filing: 1973-03-30
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Granted: 1974-02-05
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Expires: 1993-03-30
Abstract
Abstract POROUS GLASS SUPPORT MATERIALS HAVING TWO ESSENTIALLY DISTINCT ZONES OF POROSITY. AN OUTER SURFACE ZONE COMPRISES AN OUTER SHELL WITH RELATIVELY LARGE PORES OF CONTROLLED DIAMETER WHILE AN INNER ZONE COMPRISES A CORE PORTION HAVING RELATIVELY SMALLER PORES OF CONTROLLED DIAMETER. THE MATERIALS ARE MADE BY SUBJECTING POROUS GLASS BODIES OF SUBSTANTIALLY UNIFORM PORE SIZE TO A CAREFULLY CONTROLLED ALKALI ETCHING CYCLE IN WHICH ONLY THE OUTER ZONE OF THE BODIES HAVE THEIR PORES ENLARGED. THE THUS TREATED BODIES ARE PARTICULARLY USEFUL AS CHROMATOGRAPHIC SUPPORT MATERIALS WHICH, IN USE, DEMONSTRATE A DESIRABLY LOW HEIGHT EQUIVALENT THEORETICAL PLATE (HETP).
Inventors
- 👤 D Eaton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:50
CPC Classifications
C; C03; C03C; C03C11/00; C03C11/005; B; B01; B01J; B01J20/00; B01J20/28; B01J20/28054; B01J20/28078; B01J20/28088; B01J20/28092; B01J20/281; B01J20/282; B01J20/283; C03C15/00; B01J2220/00; B01J2220/50; B01J2220/54
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |