Patent US4575425A successfully refreshed from Google Patents.
US4575425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for controlling calcium oxalate scale over a wide pH range
Assignee: ECC SPECIALTY CHEMICALS Inc
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Filing: 1984-12-24
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Granted: 1986-03-11
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Expires: 2004-12-24
Abstract
Abstract The instant invention is directed to a composition useful for inhibiting precipitation of calcium oxalate in aqueous systems comprising: (a) a water soluble phosphate, phosphonate or phosphinate; and (b) a water soluble polyelectrolyte wherein the ratio of component (a) to component (b) ranges from 10:1 to 1:10. The instant invention is further directed to a method of inhibiting the precipitation and deposition of calcium oxalate scale in an aqueous system, comprising adding to said system an effective amount of the above described composition, wherein said aqueous system has a pH greater than or equal to 2.0.
Inventors
- 👤 Bennett P. Boffardi
- 👤 John P. Farkas
- 👤 Monica A. Yorke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:00
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14; C02F5/105; C02F5/12; C02F5/125
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
143 words
A method of inhibiting the precipitation and deposition of calcium oxalate scale in an aqueous system, comprising adding to said system an effective amount of (a) a compound selected from the group consisting of water soluble metaphosphates, pyrophosphates or polyphosphates of sodium, potassium, cesium, rhobidium, or ammonium, and amino tri(methylene phosphonic acid); and (b) an anionic water soluble polyelectrolyte selected from the group consisting of homopolymers of acrylic acid, homopolymers of methacrylic acid, copolymers of acrylic acid and methacrylic acid, copolymers of acrylica acid and 2-acrylamido-2-methyl propyl sulfonic acid, copolymers of methacrylic acid and 2-acrylamido-2-methyl propyl sulfonic acid, copolymers of acrylic acid and 2-hydroxypropyl acrylate, and copolymers of methacrylic acid and 2-hdroxypropyl acrylate wherein the ratio of component (a) to component (b) ranges from 10:1 to 1:10 by weight, and wherein the pH of said aqueous system ranges from about 4.0 to 6.0.
Claim 2
Independent Claim
143 words
A method of inhibiting the precipitation and deposition of calcium oxalate scale in an aqueous system, comprising adding to said system an effective amount of (a) a compound selected from the group consisting of water soluble metaphosphates, pyrophosphates or polyphosphates of sodium, potassium, cesium, rhobidium, or ammonium, and amino tri(methylene phosphonic acid); and (b) an anionic water soluble polyelectrolyte selected from the group consisting of homopolymers of acrylic acid, homopolymers of methacrylic acid, copolymers of acrylic acid and methacrylic acid, copolymers of acrylica acid and 2-acrylamido-2-methyl propyl sulfonic acid, copolymers of methacrylic acid and 2-acrylamido-2-methyl propyl sulfonic acid, copolymers of acrylic acid and 2-hydroxypropyl acrylate, and copolymers of methacrylic acid and 2-hdroxypropyl acrylate wherein the ratio of component (a) to component (b) ranges from 10:1 to 1:10 by weight, and wherein the pH of said aqueous system ranges from about 4.0 to 6.0.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said effective amount ranges from 0.1 to 1,000 ppm, based on the weight of said aqueous system.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein said ratio of component (a) to component (b) is from 1.5:1 to 1:1.5.
References Cited (Backward Citations)
US2774694A
Cited
US3449164A
Cited
US3518204A
Cited
US3692673A
Cited
US3709815A
Cited
US3709816A
Cited
US3806367A
Cited
US3898037A
Cited
US3837803A
Cited
US3890228A
Cited
US3928196A
Cited
US4108680A
Cited
US4209398A
Cited
US4118318A
Cited
JPS5440350A
Cited
JPS5459647A
Cited
JPS5481058A
Cited
JPS54125014A
Cited
US4389324A
Cited
US4255259A
Cited
GB2061249A
Cited
WO1983002607A1
Cited
WO1983002628A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-10 | 1989-09-09 | 1990-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-10 | 1993-09-09 | 1994-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-10 | 1997-09-09 | 1998-03-11 | $7700.00 | Window Closed / Lapsed |