US3891568A
Expired / Lapsed
US
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Method and composition for control of corrosion and scale formation in water systems
Assignee: Wright Chemical Corp
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Filing: 1972-08-25
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Granted: 1975-06-24
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Expires: 1992-08-25
Abstract
Abstract A composition for controlling corrosion and scale deposition in aqueous systems which comprises a phosphonate, an alkali metal molybdate salt and an alkali metal mercaptobenzothiazole or benzotriazole. In a preferred embodiment, a polyacrylate or polyacrylamide is combined with these constituents. In accordance with the method of this invention, these constituents are added to the aqueous system in amounts which are sufficient to provide a phosphonate concentration of at least 0.8 ppm, a molybdate salt concentration of at least 7 ppm and a mercaptobenzothiazole salt concentration of at least 2 ppm or benzotriazole concentration of at least 1 ppm.
Inventors
- 👤 Kazuo Nishio
- 👤 Paul G Bird
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:56
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14; C02F5/145; C23; C23F; C23F11/00; C23F11/08
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
32 words
A METHOD FOR CONTROLLING CORROSION AND SCALE DEPOSITION IN AN AQUEOUS SYSTEM, COMPRISING ADDING TO SAID SYSTEM: A FIRST CONSTITUENT SELECTED FROM THE CLASS CONSISTING OF (A) COMPOUNDS HAVING THE GENERAL FORMULA
Claim 2
Independent Claim
32 words
A METHOD FOR CONTROLLING CORROSION AND SCALE DEPOSITION IN AN AQUEOUS SYSTEM, COMPRISING ADDING TO SAID SYSTEM: A FIRST CONSTITUENT SELECTED FROM THE CLASS CONSISTING OF (A) COMPOUNDS HAVING THE GENERAL FORMULA
Claim 3
Dependent Claim
27 words
The method of claim 1 wherein said first constituent is selected from the group consisting of 1-hydroxyethylidene-1, 1-diphosphonic acid, and the alkali metal and ammonium salts thereof.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein said first constituent is selected from the group consisting of nitrilo-tri(methylene phosphonic acid), and the alkali metal and ammonium salts thereof.
Claim 5
Dependent Claim
26 words
The method of claim 1 wherein an alkali metal or ammonium salt of a polyacrylate or a partially hydrolyzed polyacrylamide is also added to said system.
Claim 6
Dependent Claim
78 words
The method of claim 1 wherein said constituents are added to said aqueous system in amounts sufficient to provide in said system from approximately 0.8 to 3 ppm of said first constituent, from approximately 7 to 14 ppm of said second constituent, and from approximately 1 to 15 ppm of said third constituent if said third constituent is benzotriazole and from approximately 2 to 15 ppm of said third constituent if said third constituent is a mercaptobenzothiazole salt.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein said second constituent is sodium molybdate.
Claim 8
Dependent Claim
12 words
The method of claim 1 wherein said third constituent is sodium mercaptobenzothiazole.
Claim 9
Dependent Claim
49 words
The method of claim 1 wherein said first constituent is selected from the class consisting of 1-hydroxyethylidene-1, 1-diphosphonic acid, nitrilo-tri(methylenephosphonic acid) and sodium salts thereof, said second constituent is sodium molybdate, and said third constituent is selected from the group consisting of benzotriazole and the sodium salts of mercaptobenzothiazole.
Claim 10
Dependent Claim
31 words
A formulation for controlling corrosion and scale deposition in aqueous systems, said formulation consisting essentially of: a first constituent selected from the class consisting of (a) compounds having the general formula
Claim 11
Dependent Claim
31 words
A formulation for controlling corrosion and scale deposition in aqueous systems, said formulation consisting essentially of: a first constituent selected from the class consisting of (a) compounds having the general formula
Claim 12
Dependent Claim
26 words
The formulation of claim 9 wherein said first constituent is selected from the group consisting of the alkali metal and ammonium salts of 1-hydroxyethylidene-1, 1-diphosphonic acid.
Claim 13
Dependent Claim
26 words
The formulation of claim 9 wherein said first constituent is selected from the group consisting of the alkali metal and ammonium salts of nitrilo-tri(methylene phosphonic acid).
Claim 14
Dependent Claim
12 words
The formulation of claim 9 wherein said second constituent is sodium molybdate.
Claim 15
Dependent Claim
12 words
The formulation of claim 9 wherein said third constituent is sodium mercaptobenzothiazole.
Claim 16
Dependent Claim
31 words
A formulation for controlling corrosion and scale deposition in aqueous systems, said formulation consisting essentially of: a first constituent selected from the class consisting of (a) compounds having the general formula
Claim 17
Dependent Claim
31 words
A formulation for controlling corrosion and scale deposition in aqueous systems, said formulation consisting essentially of: a first constituent selected from the class consisting of (a) compounds having the general formula
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |