US4575678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion monitoring
Assignee: INTEGRITI SOLUTIONS Ltd
•
Filing: 1983-01-05
•
Granted: 1986-03-11
•
Expires: 2003-01-05
Abstract
Abstract In an apparatus or installation having a metal part corroding in an electrolyte contacting the part, that part is a first electrode electrically insulated from a second electrode, for example another part of the apparatus, also contacting the electrolyte. No external electrical power is applied to the electrodes/electrolyte system. The low frequency voltage between the electrodes is observed. This voltage is a low frequency noise signal. Amplitude values of the signal are measured and subjected to an averaging computation yielding data indicating the corrosion rate of the first electrode and the nature of the corrosion.
Inventors
- 👤 Karel Hladky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:22
CPC Classifications
G; G01; G01N; G01N17/00; G01N17/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
148 words
A method of monitoring the corrosion of a metal part wherein the part constitutes a first electrode in contact with an electrolyte, comprising; connecting a high input impedance volt meter between the first electrode and a second electrode which is in contact with the electrolyte but otherwise electrically insulated from the first electrode, the second electrode corroding in the electrolyte at a rate which does not exceed the rate of corrosion of the first electrode, said electrodes and electrolyte forming a system in which no current or voltage is applied from any source external to that system, filtering the output of the volt meter to remove (1) DC components and (2) AC components of the measured voltage having a frequency greater than a predetermined threshold frequency, and monitoring the amplitude of the filtered measured voltage, to provide an indication of the rate of corrosion of the first electrode.
Claim 2
Independent Claim
148 words
A method of monitoring the corrosion of a metal part wherein the part constitutes a first electrode in contact with an electrolyte, comprising; connecting a high input impedance volt meter between the first electrode and a second electrode which is in contact with the electrolyte but otherwise electrically insulated from the first electrode, the second electrode corroding in the electrolyte at a rate which does not exceed the rate of corrosion of the first electrode, said electrodes and electrolyte forming a system in which no current or voltage is applied from any source external to that system, filtering the output of the volt meter to remove (1) DC components and (2) AC components of the measured voltage having a frequency greater than a predetermined threshold frequency, and monitoring the amplitude of the filtered measured voltage, to provide an indication of the rate of corrosion of the first electrode.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1, further including determining the standard deviation of the filtered measured voltage, to provide a measure of the rate of corrosion.
Claim 4
Dependent Claim
28 words
A method as claimed in claim 1, further including determining the root mean square of the filtered measured voltage, to provide a measure of the rate of corrosion.
Claim 5
Dependent Claim
27 words
A method as claimed in claim 1, further including determining an average of the filtered measured voltage amplitude, to provide a measure of the rate of corrosion.
Claim 6
Dependent Claim
42 words
A method as claimed in claim 1, further including monitoring the filtered measured voltage in a range of frequencies below the said threshold frequency and detecting any increase in amplitude with an increase in frequency, to provide an indication of crevice corrosion.
Claim 7
Dependent Claim
42 words
A method as claimed in claim 1, further including monitoring the amplitude of the filtered measured voltage for a predetermined period and detecting any sharp peaks in the relationship between the monitored voltage and time, to provide an indication of pitting corrosion.
Claim 8
Independent Claim
108 words
An apparatus for monitoring the corrosion of a metal part, wherein the part constitutes a first electrode in contact with an electrolyte, comprising a second electrode in contact with said electrolyte but otherwise electrically insulated from said first electrode, a high input impedance volt meter connected to said first electrode and said second electrode, means for filtering the output of the volt meter to remove (1) DC components and (2) AC components of the measured voltage having a frequency greater than a predetermined threshold frequency, and means for monitoring the output of the filtering means to provide an indication of the rate of corrosion of the first electrode.
Claim 9
Independent Claim
108 words
An apparatus for monitoring the corrosion of a metal part, wherein the part constitutes a first electrode in contact with an electrolyte, comprising a second electrode in contact with said electrolyte but otherwise electrically insulated from said first electrode, a high input impedance volt meter connected to said first electrode and said second electrode, means for filtering the output of the volt meter to remove (1) DC components and (2) AC components of the measured voltage having a frequency greater than a predetermined threshold frequency, and means for monitoring the output of the filtering means to provide an indication of the rate of corrosion of the first electrode.
Claim 10
Dependent Claim
21 words
An apparatus according to claim 7, comprising means responsive to the monitoring means for introducing a corrosion inhibitor into the electrolyte.
Claim 11
Dependent Claim
20 words
An apparatus according to claim 7, comprising means responsive to the monitoring means for introducing gas bubbles into the electrolyte.
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) | 1989-03-10 | 1989-09-09 | 1990-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-10 | 1993-09-09 | 1994-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-10 | 1997-09-09 | 1998-03-11 | $7700.00 | Window Closed / Lapsed |