US4978500A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inhibitor for metal corrosion by brine
Assignee: Individual
•
Filing: 1989-09-15
•
Granted: 1990-12-18
•
Expires: 2009-09-15
Abstract
Abstract An inhibitor composition of sodium hexametaphosphate and a water soluble orthophosphate, together with a pH adjusting, water-soluble alkali, effectively prevents corrosion of metal surfaces by sodium chloride brines. This corrosion inhibitor can be used to prevent corrosion of motor vehicles and steel reinforcing members and structures by brines formed by roadway deicing salt.
Inventors
- 👤 W. Bruce Murray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:47
CPC Classifications
C; C09; C09K; C09K3/00; C09K3/18; C09K3/185; C23; C23F; C23F11/00; C23F11/08; C23F11/18; C23F11/184; Y; Y10; Y10S; Y10S507/00; Y10S507/939
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
97 words
A method of inhibiting the corrosion of metal surfaces by brines containing from 0.5 to about 5 weight percent of sodium chloride, which comprises: a. incorporating in the brine, sodium hexametaphosphate in an amount from 100 to about 500 parts per million, and effective to form a passivating surface on said metal surface; b. also incorporating in said brine, a soluble orthophosphate in a molar proportion to said hexametaphosphate from 5 to about 10 molar parts per molar part of said hexametaphosphate; and c. adjusting the pH of said brine to a value from 6.46 to 6.9.
Claim 2
Independent Claim
97 words
A method of inhibiting the corrosion of metal surfaces by brines containing from 0.5 to about 5 weight percent of sodium chloride, which comprises: a. incorporating in the brine, sodium hexametaphosphate in an amount from 100 to about 500 parts per million, and effective to form a passivating surface on said metal surface; b. also incorporating in said brine, a soluble orthophosphate in a molar proportion to said hexametaphosphate from 5 to about 10 molar parts per molar part of said hexametaphosphate; and c. adjusting the pH of said brine to a value from 6.46 to 6.9.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein the pH of said brine is adjusted by the addition thereto of an alkali selected from the class consisting of sodium bicarbonate, sodium carbonate, sodium hydroxide.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein said pH is adjusted to a value of 6.6.
Claim 5
Dependent Claim
49 words
The method of claim 1 as applied to the prevention of corrosion by brines formed by salt applied to roadways wherein said sodium hexametaphosphate and soluble orthophosphate are applied to said roadway at total dosage from 10 to about 20 pounds per mile of twenty foot width of roadway.
Claim 6
Dependent Claim
23 words
The method of claim 4 wherein said sodium hexametaphosphate and soluble orthophosphate are admixed with salt prior to its application to a roadway.
Claim 7
Dependent Claim
24 words
The method of claim 4 wherein said sodium hexametaphosphate and soluble orthophosphate are applied to said roadway separately from the application of salt thereto.
Claim 8
Dependent Claim
26 words
The method of claim 4 wherein said sodium hexametaphosphate and soluble orthophosphate are also contain a dye to render them visible when applied to said roadway.
Claim 9
Independent Claim
108 words
A method of inhibiting the corrosion of metal surfaces by brines containing from 0.5 to about 5 weight percent of sodium chloride, which comprises: a. adding to said brine an inhibitor having a pH from about 7 to 7.5 and consisting of: (i) sodium hexametaphosphate; and (ii) a soluble orthophosphate in a molar proportion to said sodium hexametaphosphate from 5 to about 10 molar parts per molar part of said hexametaphosphate; and b. adjusting the amount of said inhibitor in said brine to provide a concentration of sodium hexametaphosphate therein from 100 to about 500 part per million, effective to form a passivating surface on said metal surface.
Claim 10
Independent Claim
108 words
A method of inhibiting the corrosion of metal surfaces by brines containing from 0.5 to about 5 weight percent of sodium chloride, which comprises: a. adding to said brine an inhibitor having a pH from about 7 to 7.5 and consisting of: (i) sodium hexametaphosphate; and (ii) a soluble orthophosphate in a molar proportion to said sodium hexametaphosphate from 5 to about 10 molar parts per molar part of said hexametaphosphate; and b. adjusting the amount of said inhibitor in said brine to provide a concentration of sodium hexametaphosphate therein from 100 to about 500 part per million, effective to form a passivating surface on said metal surface.
Claim 11
Dependent Claim
22 words
The method of claim 8 including the step of adjusting the pH of said brine to a value from 6.46 to 6.9.
Claim 12
Dependent Claim
32 words
The method of claim 9 wherein the pH of said brine is adjusted by the addition thereto of an alkali selected from the class consisting of sodium bicarbonate, sodium carbonate, sodium hydroxide.
Claim 13
Dependent Claim
18 words
The method of claim 9 wherein the pH of said brine is adjusted to a value of 6.6.
Claim 14
Dependent Claim
45 words
The method of claim 8 as applied to the prevention of corrosion by brines formed by salt applied to roadways wherein said inhibitor is applied to said roadway at a dosage from 10 to about 20 pounds per mile of twenty foot width of roadway.
Claim 15
Dependent Claim
19 words
The method of claim 12 wherein said inhibitor is admixed with salt prior to its application to a roadway.
Claim 16
Dependent Claim
20 words
The method of claim 12 wherein said inhibitor is applied to said roadway separately from the application of salt thereto.
Claim 17
Dependent Claim
21 words
The method of claim 12 wherein said inhibitor also contains a dye to render it visible when applied to said roadway.
References Cited (Backward Citations)
US1903041A
Cited
US1997256A
Cited
US2096736A
Cited
US2900222A
Cited
US2980620A
Cited
US2988509A
Cited
US3029127A
Cited
US3248249A
Cited
US3215637A
Cited
US3313650A
Cited
DE1459664A1
Cited
DE1459642A1
Cited
US3432428A
Cited
US3542686A
Cited
SU482488A1
Cited
US3869317A
Cited
US3837803A
Cited
US3933459A
Cited
GB1536660A
Cited
GB1555468A
Cited
US4303568A
Cited
US4297237A
Cited
US4448702A
Cited
US4512907A
Cited
US4634532A
Cited
US4668416A
Cited
US4849171A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-17 | 1994-06-18 | 1994-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-17 | 1998-06-18 | 1998-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-17 | 2002-06-18 | 2002-12-18 | $7700.00 | Window Closed / Lapsed |