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US 5,401,311 AGranted
Method for removing deposits from cooling water systems
AssigneeBetz Laboratories, Inc.
InventorsDonald T. Freese, Raymond M. Post, David M. Polizzotti
Life of this patent
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Abstract
Methods and compositions for removing deposits from surfaces in contact with the water of a cooling water system are disclosed. The combination of a chelant, a phosphonate or phosphate compound, and a base is effective in removing clay deposits from such surfaces.
Claims12
A method of removing clay deposits from surfaces in contact with the water of a cooling water system comprising the steps of:
- (a) maintaining the pH of said water within the range of from about 7 to about 11 throughout the entire method;
- (b) adding to said water a chelant selected from the group consisting of ethylenediaminetetraacetic acid and citric acid;
- (c) subsequently adding to said water a phosphonate or phosphate compound;
- and
- (d) blowing down said cooling water to remove said deposits.
2 more elements
A method of removing clay deposits from surfaces in contact with the water of a cooling water system consisting essentially of the steps of:
- (a) adding to said water from about 0.002-0.016 moles per liter of a chelant selected from the group consisting of ethylenediaminetetraacetic acid and citric acid;
- (b) subsequently adding to said water from about 300-20,000 parts per million of a phosphonate or phosphate compound;
- and
- (c) blowing down said cooling water to remove said deposits,
- the pH of said water being within the range of from about 7 to about 11.
2 more elements
Dependencies are inferred from the claim text.