Method of anticorrosive treatment for soft water boilers
First Claim
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1. A method of anticorrosive treatment for soft water boilers which comprises adding to a boiler water system which uses soft water at a temperature of at least 150°
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(a) at least one phosphorous compound selected from the group consisting of polyphosphoric acids, orthophosphoric acids and organophosphoric acids, in an amount of 10-200 mg/l, (b) at least one carboxylic acid compound selected from the group consisting of aliphatic hydroxycarboxylic acids and amino acids, in an amount of 40-500 mg/l, and (c) at least one metal compound that releases in water metal ions selected from the group consisting of tin ions, manganese ions and nickel ions, in an amount of 0.5-50 mg/l as metal ion, wherein the weight ratio of the compound (b) to the metal ions of the compound (c) is 3 or more, thereby preventing corrosion of iron family metals in the boiler water system.
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Abstract
A method of anticorrosive treatment for soft water boilers to prevent iron family metals from corrosion, especially from pitting corrosion, which is characterized by adding, to a boiler water system using soft water at a high temperature, (a) a specific amount of a phosphorus compound, (b) a specific amount of a carboxylic acid compound and (c) a specific amount of a metal compound.
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8 Claims
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1. A method of anticorrosive treatment for soft water boilers which comprises adding to a boiler water system which uses soft water at a temperature of at least 150°
- C.;
(a) at least one phosphorous compound selected from the group consisting of polyphosphoric acids, orthophosphoric acids and organophosphoric acids, in an amount of 10-200 mg/l, (b) at least one carboxylic acid compound selected from the group consisting of aliphatic hydroxycarboxylic acids and amino acids, in an amount of 40-500 mg/l, and (c) at least one metal compound that releases in water metal ions selected from the group consisting of tin ions, manganese ions and nickel ions, in an amount of 0.5-50 mg/l as metal ion, wherein the weight ratio of the compound (b) to the metal ions of the compound (c) is 3 or more, thereby preventing corrosion of iron family metals in the boiler water system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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