Patent US3900338A successfully refreshed from Google Patents.
US3900338A
Expired / Lapsed
US
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Water soluble block polymers used as silt control agents
Assignee: Calgon Corp
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Filing: 1974-04-30
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Granted: 1975-08-19
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Expires: 1994-04-30
Abstract
Abstract Water-soluble block polymers of the A-B-A type wherein the A block is derived from a water-soluble monomer and the B block is derived from N-vinyl pyrrolidone for use as silt control agents.
Inventors
- 👤 Regis Robert Rumpf
- 👤 David Elmer Farley
- 👤 Lawrence James Guilbault
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:50
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12; C02F1/00; C02F1/52; C02F1/54; C08; C08F; C08F8/00; C08F8/12
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
90 words
A METHOD OF REMOVING ALLUVIUM AND SLIT DEPOSITS AND INHIBITING THE DEPOSITION OF ALLUVIUM AND SILT IN AQUEOUS SYSTEMS COMPRISING ADDING TO THE WATER IN SAID AQUEOUS SYSTEM LEAST 0.05 PPM OF A POLYMER OF THE FORMULA A-B-A WHEREIN THE A BLOCK REPRESENTS FROM 10 TO 100,000 MER UNITS OF ACRYLAMIDE AND THE B BLOCK REPRESENTS FROM 10 TO 5,000 MER UNITS OF N-VINYLPYRROLIDONE, FLOWING SAID WATER IN CONTACT WITH THE DEPOSITS IN SAID SYSTEM THEREBY FORMING A FLOCK AND FLUSHING SAID WATER CONTAINING SAID FLOCK OUT OF SAID SYSTEM.
Claim 2
Independent Claim
90 words
A METHOD OF REMOVING ALLUVIUM AND SLIT DEPOSITS AND INHIBITING THE DEPOSITION OF ALLUVIUM AND SILT IN AQUEOUS SYSTEMS COMPRISING ADDING TO THE WATER IN SAID AQUEOUS SYSTEM LEAST 0.05 PPM OF A POLYMER OF THE FORMULA A-B-A WHEREIN THE A BLOCK REPRESENTS FROM 10 TO 100,000 MER UNITS OF ACRYLAMIDE AND THE B BLOCK REPRESENTS FROM 10 TO 5,000 MER UNITS OF N-VINYLPYRROLIDONE, FLOWING SAID WATER IN CONTACT WITH THE DEPOSITS IN SAID SYSTEM THEREBY FORMING A FLOCK AND FLUSHING SAID WATER CONTAINING SAID FLOCK OUT OF SAID SYSTEM.
Claim 3
Dependent Claim
12 words
A process as in claim 1 wherein the acrylamide is partially hydrolyzed.
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) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |