Claims
- 1. A method for inhibiting formation of scale in an aqueous steam generating boiler system comprising a chemical treatment consisting essentially of adding to the water in the system scale inhibiting amounts of a composition comprising:
- (1) a copolymer of maleic acid and allyl sulfonic acid or a water soluble salt thereof, said copolymer having a molecular weight of from about 800 to about 25,000 and an allyl sulfonic acid to maleic acid mole ratio of about 1:3 to 3:1; and
- (2) from about 0.25 to about 4 parts by weight, per part by weight of said copolymer or copolymer salt, of hydroxyethylidene-1,1-diphosphonic acid or a water soluble salt thereof; and further adding to the water
- (3) from about 500 to about 0.1 parts by weight, per part by weight of said copolymer or copolymer salt, of a water soluble sodium phosphate hardness precipitating agent.
- 2. Method as defined in claim 1 in which from about 15 to about 1.5 parts of sodium phosphate hardness precipitating agent are added perpart by weight of copolymer or copolymer salt.
- 3. Method as defined in claim 2 in which the weight ratio of additives (1) and (2) is about 1:1.
- 4. Method as defined in claim 3 in which the allyl sulfonic acid to maleic acid ratio in additive (1) is about 1:1.
- 5. Method as defined in claim 4 in which additive (1) is a copolymer having a molecular weight of about 1,000 to 15,000.
- 6. Method as defined in claim 1 in which the additives are added together as an aqueous solution consisting essentially of (1), (2) and (3).
- 7. A method for inhibiting formation of scale in an aqueous steam generating boiler system comprising adding to the boiler water an aqueous solution consisting essentially of (1) a copolymer of maleic acid and allyl sulfonic acid, said copolymer having a molecular weight of from about 1,000 to about 15,000 and an allyl sulfonic acid to maleic acid mole ratio of about 1:1; (2) hydroxyethylidene-1,1-diphosphonic acid; and (3) a water soluble sodium phosphate hardness precipitating agent; said copolymer (1) and said phosphonic acid (2) being present in a weight ratio of about 1:1; said copolymer (1) and sodium phosphate hardness precipitating agent (3) being present in a weight ratio of from about 1:15 to about 2:3; and said solution being added in an amount sufficient to provide a total amount of (1), (2) plus (3) of from about 20 to about 2500 parts per million of system water in the boiler.
Parent Case Info
This is a division of application Ser. No. 559,517, filed Dec. 8, 1983, now U.S. Pat. No. 4,600,524.
US Referenced Citations (12)
Foreign Referenced Citations (9)
Number |
Date |
Country |
0009304 |
Feb 1980 |
EPX |
0122013 |
Oct 1984 |
EPX |
1233259 |
May 1971 |
GBX |
1463173 |
Feb 1977 |
GBX |
1539974 |
Feb 1979 |
GBX |
1575173 |
Sep 1980 |
GBX |
1581968 |
Dec 1980 |
GBX |
1589109 |
May 1981 |
GBX |
2105319 |
Mar 1983 |
GBX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
559517 |
Dec 1983 |
|