US3959167A
Expired / Lapsed
US
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Method and composition of inhibiting scale
Assignee: WR Grace and Co Conn
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Filing: 1973-12-10
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Granted: 1976-05-25
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Expires: 1993-12-10
Abstract
Abstract The invention disclosed relates to a method for using a new improved composition for inhibiting or preventing accumulation of scale or the like on heating surfaces in an aqueous system. The present composition includes an acrylic polymer, a water-soluble chelant, and an organophosphonic acid and/or their water-soluble salts. In a preferred embodiment, the composition is composed of sodium polymethylacrylate, nitrilotriacetic acid and hydroxyethylidene diphosphonic acid as its water-soluble salts.
Inventors
- 👤 Chih Ming Hwa
- 👤 Dionisio Guerrero Cuisia
- 👤 Murrell Leon Salutsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:48
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
139 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said systems of 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of an acrylic polymer selected from the group consisting of polymethacrylic acid and polyacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of a water-soluble chelant selected from the group consisting of nitrilotriacetic acid and its water soluble salts, ethylenediamine tetraacetic acid and its water soluble salts; and 0.1 to 100 parts by weight of hydroxyalkylidene diphosphonic acid having the structural formula of ##EQU2## wherein R denotes an alkyl group having from 1 to 5 carbon atoms, and water-soluble salts thereof.
Claim 2
Independent Claim
139 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said systems of 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of an acrylic polymer selected from the group consisting of polymethacrylic acid and polyacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of a water-soluble chelant selected from the group consisting of nitrilotriacetic acid and its water soluble salts, ethylenediamine tetraacetic acid and its water soluble salts; and 0.1 to 100 parts by weight of hydroxyalkylidene diphosphonic acid having the structural formula of ##EQU2## wherein R denotes an alkyl group having from 1 to 5 carbon atoms, and water-soluble salts thereof.
Claim 3
Independent Claim
119 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of an acrylic polymer selected from the group consisting of polymethacrylic acid and polyacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of a water-soluble chelant selected from the group consisting of nitrilotriacetic acid and its water soluble salts, ethylenediamine tetraacetic acid and its water soluble salts and 0.1 to 100 parts by weight of amino-trimethylenephosphonic acid and its water-soluble salts.
Claim 4
Independent Claim
119 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of an acrylic polymer selected from the group consisting of polymethacrylic acid and polyacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of a water-soluble chelant selected from the group consisting of nitrilotriacetic acid and its water soluble salts, ethylenediamine tetraacetic acid and its water soluble salts and 0.1 to 100 parts by weight of amino-trimethylenephosphonic acid and its water-soluble salts.
Claim 5
Independent Claim
91 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of a polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of nitrilotriacetic acid and water-soluble salts thereof; and 0.1 to 100 parts by weight of hydroxyethylidene diphosphonic acid and water-soluble salts thereof.
Claim 6
Independent Claim
91 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of a polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of nitrilotriacetic acid and water-soluble salts thereof; and 0.1 to 100 parts by weight of hydroxyethylidene diphosphonic acid and water-soluble salts thereof.
Claim 7
Independent Claim
90 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of ethylenediamine tetraacetic acid and water-soluble salts thereof; 0.1 to 100 parts by weight of hydroxyethylidene diphosphonic acid and water-soluble salts thereof.
Claim 8
Independent Claim
90 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of ethylenediamine tetraacetic acid and water-soluble salts thereof; 0.1 to 100 parts by weight of hydroxyethylidene diphosphonic acid and water-soluble salts thereof.
Claim 9
Independent Claim
88 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of nitrilotriacetic acid and its water-soluble salts; 0.1 to 100 parts by weight of amino-trimethylenephosphonic acid and its water-soluble salts.
Claim 10
Independent Claim
88 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous systems, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of nitrilotriacetic acid and its water-soluble salts; 0.1 to 100 parts by weight of amino-trimethylenephosphonic acid and its water-soluble salts.
Claim 11
Independent Claim
90 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous system, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of ethylenediamine tetraacetic acid and its water-soluble salts; and 0.1 to 100 parts by weight of amino-trimethylenephosphonic acid and its water-soluble salts.
Claim 12
Independent Claim
90 words
A method for inhibiting deposits of scale, sludge and other foulants in aqueous system, said method consisting essentially of adding to the said system from 0.01 to 500 parts per million of a mixture of 0.1 to 100 parts by weight of polymethacrylic acid and water-soluble salts thereof, said polymer having a weight average molecular weight of from about 1,000 to 1,000,000; 0.1 to 100 parts by weight of ethylenediamine tetraacetic acid and its water-soluble salts; and 0.1 to 100 parts by weight of amino-trimethylenephosphonic acid and its water-soluble salts.
Claim 13
Dependent Claim
45 words
The method of claim 1 wherein the acrylic polymer is present in an amount of 2-6 parts by weight, the chelant is present in an amount of 0.5-2 parts by weight and the diphosphonic acid is present in an amount of 0.5-2 parts by weight.
Claim 14
Dependent Claim
49 words
The method of claim 2 wherein the acrylic polymer is present in an amount of 2-6 parts by weight, the chelant is present in an amount of 0.5-2 parts by weight and the amino-trimethylenephosphonic acid and its water-soluble salts is present in an amount of 0.5-2 parts by weight.
Claim 15
Dependent Claim
58 words
The method of claim 3 wherein the polymethacrylic acid and water-soluble salts thereof is present in an amount of 2-6 parts by weight, the nitrilotriacetic acid and water-soluble salts thereof is present in an amount of 0.5-2 parts by weight and the hydroxyethylidene diphosphonic acid and water-soluble salts thereof is present in amount of 0.5-2 parts by weight.
Claim 16
Dependent Claim
59 words
The method of claim 4 wherein the polymethacrylic acid and water-soluble salts thereof is present in amounts of 2-6 parts by weight, the ethylenediamine tetraacetic acid and water-soluble salts thereof is present in an amount of 0.5-2 parts by weight, and the hydroxyethylidene diphosphonic acid and water-soluble salts thereof is present in an amount of 0.5-2 parts by weight.
Claim 17
Dependent Claim
58 words
The method of claim 5 wherein the polymethacrylic acid and water-soluble salts thereof is present in an amount of 2-6 parts by weight, the nitrilotriacetic acid and its water-soluble salts is present in an amount of 0.5-2 parts by weight and the amino-trimethylenephosphonic acid and its water-soluble salts is present in an amount of 0.5-2 parts by weight.
Claim 18
Dependent Claim
59 words
The method of claim 6 wherein the polymethacrylic acid and water-soluble salts thereof is present in an amount of 2-6 parts by weight, the ethylenediamine tetraacetic acid and its water-soluble salts is present in an amount of 0.5-2 parts by weight and the amino-trimethylenephosphonic acid and its water-soluble salts is present in an amount of 0.5-2 parts by weight.
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) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |