US4116782A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion prevention system
Assignee: Dow Chemical Co
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Filing: 1977-03-07
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Granted: 1978-09-26
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Expires: 1997-03-07
Abstract
Abstract A method to reduce corrosion of a metal conduit in an aqueous electrolyte conduit system including a nonmetallic conduit system physically attached to the metal conduit comprising impressing an electric potential between an electrode positioned at least partially within the nonmetallic conduit and a ground, the potential being at least about the difference between the electrochemical reaction potentials of reations occurring at the electrode and at the metal conduit.
Inventors
- 👤 Charles K. Bon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:17
CPC Classifications
C; C23; C23F; C23F13/00; C23F13/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
74 words
A method to reduce corrosion of a grounded metal conduit in an aqueous electrolyte conduit system including a nonmetallic conduit system physically attached to the metal conduit comprising impressing an electric potential between an anode positioned at least partially within the nonmetallic conduit and a ground, the potential being at least about the difference between the electrochemical reaction potentials, at the reaction temperature, of reactions occurring at the anode and at the metal conduit.
Claim 2
Independent Claim
74 words
A method to reduce corrosion of a grounded metal conduit in an aqueous electrolyte conduit system including a nonmetallic conduit system physically attached to the metal conduit comprising impressing an electric potential between an anode positioned at least partially within the nonmetallic conduit and a ground, the potential being at least about the difference between the electrochemical reaction potentials, at the reaction temperature, of reactions occurring at the anode and at the metal conduit.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein the impressed potential is sufficient to minimize corrosion of an iron or iron alloy conduit when the electrolyte consists essentially of an aqueous sodium chloride solution.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein the impressed potential is from about 1.5 to about 2.0 volts.
Claim 5
Independent Claim
163 words
A system to reduce corrosion of a grounded metal conduit with an inner surface in contact with an electrolyte comprising: (a) a source of stray electric current, said source adapted to be in contact with the electrolyte; (b) a conduit, having at least a nonmetallic inner surface, physically attached to said stray conduit source adapted to carry the electrolyte from said stray current source to a metal conduit; (c) a grounded metal conduit, physically attached to said nonmetallic conduit, adapted to carry the electrolyte from said nonmetal conduit; (d) an anode spaced apart from said metal conduit and physically attached to said nonmetallic conduit, said anode adapted to be in electric contact with the electrolyte within said nonmetallic conduit; (e) a means to impress a predetermined electric potential between said electrode and a ground, the potential being at least equal to about the difference between the electrochemical reaction potentials, at the reaction temperature, of reactions occurring at said anode and said metal conduit.
Claim 6
Independent Claim
163 words
A system to reduce corrosion of a grounded metal conduit with an inner surface in contact with an electrolyte comprising: (a) a source of stray electric current, said source adapted to be in contact with the electrolyte; (b) a conduit, having at least a nonmetallic inner surface, physically attached to said stray conduit source adapted to carry the electrolyte from said stray current source to a metal conduit; (c) a grounded metal conduit, physically attached to said nonmetallic conduit, adapted to carry the electrolyte from said nonmetal conduit; (d) an anode spaced apart from said metal conduit and physically attached to said nonmetallic conduit, said anode adapted to be in electric contact with the electrolyte within said nonmetallic conduit; (e) a means to impress a predetermined electric potential between said electrode and a ground, the potential being at least equal to about the difference between the electrochemical reaction potentials, at the reaction temperature, of reactions occurring at said anode and said metal conduit.
Claim 7
Dependent Claim
24 words
The system of claim 4 wherein the metal conduit is an iron or iron alloy member and the nonmetallic conduit is an electric insulator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-25 | 1982-03-27 | 1982-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-25 | 1986-03-27 | 1986-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-25 | 1990-03-27 | 1990-09-26 | $7700.00 | Window Closed / Lapsed |