US4828795A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Systems inhibited against corrosion and/or scale deposition
Assignee: FMC Corp
•
Filing: 1987-06-22
•
Granted: 1989-05-09
•
Expires: 2007-06-22
Abstract
Abstract Aqueous or partly aqueous systems are treated against the corrosion of metals, especially ferrous metals, in contact therewith, and/or against scale deposition therefrom, by adding to these systems from 0.1 to 50 000 ppm of 2-hydroxyphosphonoacetic acid having the formula I ##STR1## or a water-soluble salt thereof.
Inventors
- 👤 Barry Cook
- 👤 Norman Richardson
- 👤 Joseph Tames
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:48
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C23F11/10; C23F11/167; C23F11/1676; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14; C07; C07F; C07F9/00; C07F9/02; C07F9/28; C07F9/38; C07F9/3804; C07F9/3808; C09; C09K; C09K5/00; C09K5/20; C10; C10M; C10M173/00; C10M173/02; C23F14/00; C23F14/02; C10M2201/00; C10M2201/02; C10M2215/00; C10M2215/02; C10M2215/04; C10M2215/042; C10M2223/00; C10M2223/06; C10M2223/061; C10M2223/065; C10N; C10N2030/00; C10N2030/12; C10N2040/00; C10N2040/08; C10N2040/20; C10N2040/22; C10N2050/00; C10N2050/01
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
43 words
A method of inhibiting scale formation on and corrosion of metal surfaces, comprising contacting said surfaces with a scale forming or corrosive medium which contains 1 to about 5 ppm of 2-hydroxyphosphonoacetic acid, or a salt thereof which is soluble in the medium.
Claim 2
Independent Claim
43 words
A method of inhibiting scale formation on and corrosion of metal surfaces, comprising contacting said surfaces with a scale forming or corrosive medium which contains 1 to about 5 ppm of 2-hydroxyphosphonoacetic acid, or a salt thereof which is soluble in the medium.
Claim 3
Dependent Claim
56 words
The method according to claim 1, wherein the medium contains metal ions selected from the group consisting of calcium magnesium or mixtures thereof, and the medium and metal surfaces are those contained in a cooling system, a steam generating system, a saline evaporator, a hydrostatic cooker, a gas scrubbing system or a closed circuit heating system.
Claim 4
Dependent Claim
48 words
The method according to claim 1, wherein the 2-hydroxyphosphonoacetic acid or salt thereof is present in conjunction with at least one member selected from the group consisting of a dispersing or threshold agent, a precipitating agent, an oxygen scavenger, a sequestering agent, an antifoaming agent or a biocide.
Claim 5
Dependent Claim
12 words
The method according to claim 1 wherein the medium further comprises triethanolamine.
Claim 6
Dependent Claim
28 words
The method according to claim 4 wherein triethanolamine is present in an amount such that the weight ratio of 2-hydroxyphosphonoacetic acid to triethanolamine is from 2:1 to 1:20.
Claim 7
Dependent Claim
22 words
The method according to claim 1, wherein the 2-hydroxyphosphonoacetic acid or salt thereof is present in conjunction with a different corrosion inhibitor.
References Cited (Backward Citations)
DE1045373B
Cited
US3032500A
Cited
US3719598A
Cited
US4057511A
Cited
US3933427A
Cited
DE2310450A1
Cited
US4105551A
Cited
US4042324A
Cited
DE2505435A1
Cited
DE2632774A1
Cited
US4243417A
Cited
JPS552218A
Cited
US4689200A
Cited
JPS6417115A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |