US3645684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fractionation of silica aerosols
Assignee: Cities Service Co
•
Filing: 1970-07-01
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Granted: 1972-02-29
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Expires: 1990-07-01
Abstract
Abstract Pigmentary silica is produced by hydrolysis of silicon tetrafluoride in hot flame gases. The silica in the resultant aerosol is then agglomerated and the silica is thereafter filtered from the gases at a temperature above the dew point. The concentration of silica in the aerosol is substantially the same at filteration as when produced, i.e., little or none of the agglomerated silica is permanently separated from the aerosol prior to filtration.
Inventors
- 👤 George L De Cuir
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:32
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/28; C09C1/30; C09C1/3009; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/18; C01B33/181; C01B33/183; C01B33/184; C01P; C01P2004/00; C01P2004/50
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
24 words
The process of claim 1 wherein the aerosol is filtered at a temperature within the range of about 300* F. to about 600* F.
Claim 2
Dependent Claim
15 words
The process of claim 1 wherein the silica particles are flocculated within a centrifugal agglomerator.
Claim 3
Dependent Claim
15 words
The process of claim 1 wherein the silica particles are flocculated within a tubular agglomerator.
Claim 4
Dependent Claim
15 words
The process of claim 1 wherein the silica particles are flocculated within an electrostatic precipitator.
Claim 5
Dependent Claim
24 words
The process of claim 1 wherein the aerosol is filtered at a temperature within the range of about 300* F. to about 450* F.
Claim 6
Dependent Claim
14 words
The process of claim 6 wherein the aerosol is filtered with a Teflon media.
Claim 7
Dependent Claim
14 words
The process of claim 6 wherein the aerosol is filtered with a Nomex media.
Claim 8
Dependent Claim
30 words
The process of claim 1 wherein the concentration of silica in the aerosol does not exceed about 12 grains per standard cubic foot of the gaseous fraction of the aerosol.
Claim 9
Dependent Claim
30 words
The process of claim 1 wherein at least about 10 square feet of filter media is provided for each pound per hour of silica which is passed to the filter.
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) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |