Patent US3671448A successfully refreshed from Google Patents.
US3671448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods of scale inhibition using substoichiometric amounts of amino alcohol and phosphonic acids
Assignee: Monsanto Co
•
Filing: 1970-09-10
•
Granted: 1972-06-20
•
Expires: 1990-09-10
Abstract
Abstract The precipitation of scale-forming materials in an aqueous system is inhibited by adding substoichiometric amounts of a precipitation inhibitor which consists of a mixture of an amino alcohol such as triethanolamine and certain phosphonic acids, such as amino tri(methylene phosphonic acid), to said system.
Inventors
- 👤 Xavier Kowalski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:38
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14; C11; C11D; C11D3/00; C11D3/16; C11D3/26; C11D3/30; C11D3/36; C11D3/361; C11D3/364
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
31 words
The method of claim 1 wherein the scale-forming material is selected from the group consisting of alkaline earth metal carbonates, sulfates, oxalates, phosphates, fluorides, silicates, transition metal hydroxides, or mixtures thereof.
Claim 2
Dependent Claim
23 words
The method of claim 1 wherein the mole ratio of precipitation inhibitor to scale-forming cation material is from about 1:2.5 to about 1:10,000.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein the amino alcohol is triethanolamine and the weight ratio of phosphonic acid to amino alcohol is from about 0.25:1 to about 1:1.
Claim 4
Dependent Claim
14 words
The method of claim 4 wherein the scale-forming material is an iron hydroxy compound.
Claim 5
Dependent Claim
28 words
The method of claim 4 wherein the precipitation inhibitor is present in the system at concentrations from about 0.1 part per million to about 500 parts per million.
Claim 6
Independent Claim
37 words
A method of inhibiting the precipitation of iron hydroxy compounds in an alkaline aqueous system containing calcium and magnesium ions, comprising adding threshold amounts of a mixture of triethanolamine and amino tri(methylene phosphonic acid) to said system.
Claim 7
Dependent Claim
20 words
A method of claim 7 wherein the alkaline aqueous system has a pH of from about 6.5 to about 12.
Claim 8
Dependent Claim
23 words
The method of claim 8 wherein the mole ratio of said mixture to iron hydroxy compound is from about 1:2.5 to about 1:10,000.
Claim 9
Dependent Claim
27 words
The method of claim 8 wherein the mixture is present in the system at concentrations from about 0.1 part per million to about 500 parts per million.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |