US3633099A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and apparatus for determining crevice corrosion by polarization techniques
Assignee: United States Department of the Interior
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Filing: 1969-06-30
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Granted: 1972-01-04
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Expires: 1989-06-30
Abstract
Abstract Crevice corrosion is detected and its extent is qualitatively measured by use of a two-electrode, polarization-type probe. The two electrodes are fabricated of the same metal and have substantially equal surface areas. At least one of the electrodes is shaped to define a crevice area of relatively narrow width. The crevice area may be formed by cutting or milling a slot in the electrodes, by grooving or threading the electrodes or by encircling the electrodes with a sleevelike element of a nonconducting material.
Inventors
- 👤 Russell B Richman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:33
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
159 words
A device for the detection and measurement of crevice corrosion by polarization techniques which comprises: a. a pair of elongated electrodes fabricated of the same metal, each of the electrodes having substantially equal surface areas and at least one of the electrodes being provided with an extended crevice area, said extended crevice area formed by a sleevelike member nonconductive to electricity encircling a portion of at least one of the electrodes to define an extended crevice area between the member and the electrode; b. a base member supporting the electrodes in a fixed physical relationship for exposure to a test environment, the base member maintaining the electrodes in electrical isolation from each other and from the base member; c. electrical conducting members communicating between a terminal point of each electrode and a point external to the test environment, and d. electrical means, adapted to produce a signal representative of corrosion onset and intensity, operably connected to said conducting members.
Claim 2
Independent Claim
159 words
A device for the detection and measurement of crevice corrosion by polarization techniques which comprises: a. a pair of elongated electrodes fabricated of the same metal, each of the electrodes having substantially equal surface areas and at least one of the electrodes being provided with an extended crevice area, said extended crevice area formed by a sleevelike member nonconductive to electricity encircling a portion of at least one of the electrodes to define an extended crevice area between the member and the electrode; b. a base member supporting the electrodes in a fixed physical relationship for exposure to a test environment, the base member maintaining the electrodes in electrical isolation from each other and from the base member; c. electrical conducting members communicating between a terminal point of each electrode and a point external to the test environment, and d. electrical means, adapted to produce a signal representative of corrosion onset and intensity, operably connected to said conducting members.
Claim 3
Dependent Claim
36 words
The device of claim 1 wherein said electrical means comprise means for impressing a known potential across the electrodes and measuring means to determine magnitude of current flow across the electrodes resulting from the impressed potential.
Claim 4
Dependent Claim
45 words
The device of claim 1 wherein the member nonconductive to electricity comprises at least one beadlike element surrounding a major portion of at least one of the electrodes, said electrode being of generally cylindrical shape, and forming in cooperation with the electrode an annular crevice.
Claim 5
Dependent Claim
70 words
The device of claim 3 wherein the beadlike element is axially pierced to form a bore extending through the element, a portion of the bore substantially conforming in diameter to the diameter of the electrode and the remaining portion of the bore having a diameter greater than that of the electrode so as to form a crevice having a width in the range of about 2 to about 50 mils.
Claim 6
Dependent Claim
27 words
The device of claim 2 wherein the extended crevice region is formed by grooving at least one of the electrodes over a substantial portion of its length.
Claim 7
Dependent Claim
41 words
The device of claim 5 wherein said grooving comprises threading and wherein a threaded collar fabricated of a nonconductive material providing a loose mating fit with the electrode forms in cooperation with the electrode an extended crevice region of controlled width.
Claim 8
Independent Claim
176 words
A device for the detection and measurement of crevice corrosion by polarization techniques which comprises: a. a pair of elongated electrodes fabricated of the same metal, each of the electrodes having substantially equal surface areas and at least one of the electrodes being provided with an extended crevice area, said extended crevice area formed by threading at least one of the electrodes over a substantial portion of its length and wherein a threaded collar fabricated of a nonconductive material providing a loose mating fit with the electrode forms in cooperation with the electrode an extended crevice region of controlled width; b. a base member supporting the electrodes in a fixed physical relationship for exposure to a test environment, the base member maintaining the electrodes in electrical isolation from each other and from the base member; c. electrical conducting members communicating between a terminal point of each electrode and a point external to the test environment, and d. electrical means, adapted to produce a signal representative of corrosion onset and intensity, operably connected to said conducting members.
Claim 9
Independent Claim
176 words
A device for the detection and measurement of crevice corrosion by polarization techniques which comprises: a. a pair of elongated electrodes fabricated of the same metal, each of the electrodes having substantially equal surface areas and at least one of the electrodes being provided with an extended crevice area, said extended crevice area formed by threading at least one of the electrodes over a substantial portion of its length and wherein a threaded collar fabricated of a nonconductive material providing a loose mating fit with the electrode forms in cooperation with the electrode an extended crevice region of controlled width; b. a base member supporting the electrodes in a fixed physical relationship for exposure to a test environment, the base member maintaining the electrodes in electrical isolation from each other and from the base member; c. electrical conducting members communicating between a terminal point of each electrode and a point external to the test environment, and d. electrical means, adapted to produce a signal representative of corrosion onset and intensity, operably connected to said conducting members.
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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |