Corrosion inhibitor
US4384979A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 4, 1981 |
| Grant date | May 24, 1983 |
| Priority date | — |
| Expiry date | Nov 4, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23F11/08
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The waters used for cooling generally contain hard ions of the group consisting of calcium and magnesium ions concentration of from about 10 to 600 parts per million. Such waters also contain bicarbonate ions. When cooling waters are recirculated through a cooling tower, they are saturated with oxygen and tend to be corrosive and tend to promote formation of calciferous scale. Such propensities are inhibited by the injection of appropriate chemicals so that the inhibited water contains dispersants effective in dispersing incipient calcium compounds and inhibiting calciferous scale, so that the inhibited water contains a plurality of components forming a dynamic layer on metal surfaces protecting such metal from oxidation. The inhibited water contains about 1 part per million of polyacrylic acid having a molecular weight of about 1,000 and terminated by thioglycolic acid, plus about 2 parts per million of dispersants comprising both sodium sulfonate dispersants and phosphate ester salt types of dispersants plus about 300 parts per billion of a mixture of organic phosphonates selected from the group consisting of diphosphonates, triphosphonates, tetraphosphonates and polyphosphonates…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.