US4189367A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for testing ion selective electrodes in continuous measuring systems
Assignee: Leeds and Northrup Co
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Filing: 1978-10-19
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Granted: 1980-02-19
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Expires: 1998-10-19
Abstract
Abstract The membrane of an ion selective electrode is tested for damage while it is being used for continuous measurement by sending a test current through the electrode system and measuring the voltage change produced. If the voltage change does not reach the value expected with an intact high resistance electrode, a defective electrode is indicated. A reverse current of the same magnitude and duration is then sent through the electrode system.
Inventors
- 👤 James G. Connery
- 👤 Robert D. Jurenko
- 👤 Earl W. Shaffer, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:20
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/4163; G01N27/4165; G01N27/28; G01N27/30; G01N27/333
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
122 words
A method for testing the integrity of the ion selective membrane of an ion selective electrode system while continuously measuring the concentration of said ion in a solution, comprising the steps of: passing a first current through said electrode system; passing a second current through said electrode system in an opposite direction to said first current and of magnitude and duration sufficient to cancel any charge remaining in said electrode system as a result of said first current; and measuring the total change in voltage across said electrode system as a result of the flow of current so that a measured voltage change to a value below that expected for an electrode system having an intact membrane indicates damage to said membrane.
Claim 2
Independent Claim
122 words
A method for testing the integrity of the ion selective membrane of an ion selective electrode system while continuously measuring the concentration of said ion in a solution, comprising the steps of: passing a first current through said electrode system; passing a second current through said electrode system in an opposite direction to said first current and of magnitude and duration sufficient to cancel any charge remaining in said electrode system as a result of said first current; and measuring the total change in voltage across said electrode system as a result of the flow of current so that a measured voltage change to a value below that expected for an electrode system having an intact membrane indicates damage to said membrane.
Claim 3
Dependent Claim
30 words
The method of claim 1 in which the total change in voltage across said electrode system is a result of the flow of one of said first and second currents.
Claim 4
Dependent Claim
29 words
The method of claim 1 in which the total change in voltage across said electrode system is a result of the flow of both said first and second currents.
Claim 5
Dependent Claim
54 words
The method of claim 1, 2, or 3 in which the current for which the voltage change is measured is of a magnitude and duration such that for the existing temperature of the glass membrane it will produce across the electrode system at least a predetermined voltage change if the membrane is not damaged.
Claim 6
Independent Claim
141 words
A method for testing the integrity of the ion selective membrane of an ion selective electrode system while continuously measuring the concentration of said ion in a solution, comprising the steps of: passing a test current through said electrode system, said test current being of a magnitude and duration such that for the existing temperature of the glass membrane it will produce at least a predetermined voltage change across the electrode system if the membrane is not damaged; measuring the change in voltage across said electrode system as a result of said test current flow so that a damaged membrane is indicated when said voltage change is less than said predetermined amount; and passing another current through said electrode system in an opposite direction to said test current to remove any effect on said electrode system caused by said test current.
Claim 7
Independent Claim
141 words
A method for testing the integrity of the ion selective membrane of an ion selective electrode system while continuously measuring the concentration of said ion in a solution, comprising the steps of: passing a test current through said electrode system, said test current being of a magnitude and duration such that for the existing temperature of the glass membrane it will produce at least a predetermined voltage change across the electrode system if the membrane is not damaged; measuring the change in voltage across said electrode system as a result of said test current flow so that a damaged membrane is indicated when said voltage change is less than said predetermined amount; and passing another current through said electrode system in an opposite direction to said test current to remove any effect on said electrode system caused by said test current.
Claim 8
Independent Claim
185 words
A method for testing the integrity of the ion selective membrane of an ion selective electrode system while continuously measuring the concentration of said ion in a solution, comprising the steps of: passing a first test current through said electrode system, said test current being of a magnitude and duration such that for the existing temperature of the glass membrane it will produce at least a predetermined voltage change across the electrode system if the membrane is not damaged; measuring the change in voltage across said electrode system as a result of said first test current flow; passing a second test current of magnitude equal to said first test current through said electrode system in an opposite direction to said first test current and for the same duration; measuring the change in voltage across said electrode system as a result of said second test current flow; and subtracting said change in voltage due to said second test current from said change in voltage due to said first current so that a damaged membrane is indicated when the resulting difference is less than a predetermined amount.
Claim 9
Independent Claim
185 words
A method for testing the integrity of the ion selective membrane of an ion selective electrode system while continuously measuring the concentration of said ion in a solution, comprising the steps of: passing a first test current through said electrode system, said test current being of a magnitude and duration such that for the existing temperature of the glass membrane it will produce at least a predetermined voltage change across the electrode system if the membrane is not damaged; measuring the change in voltage across said electrode system as a result of said first test current flow; passing a second test current of magnitude equal to said first test current through said electrode system in an opposite direction to said first test current and for the same duration; measuring the change in voltage across said electrode system as a result of said second test current flow; and subtracting said change in voltage due to said second test current from said change in voltage due to said first current so that a damaged membrane is indicated when the resulting difference is less than a predetermined amount.
Claim 10
Dependent Claim
126 words
In a pH measuring system which periodically samples the voltage output between a glass electrode and an associated reference electrode in a solution being measured, apparatus for testing the glass electrode between consecutive samples to determine if the glass membrane is cracked, comprising: means for passing a test current through said electrode combination for a period which is at least less than half the sampling period and for automatically passing another current of the same magnitude in the opposite direction for a period of the same duration as said test current; and means for measuring the voltage change between said reference and said glass electrode as a result of said test current for indicating a cracked electrode if said voltage change is below a minimum amount.
Claim 11
Dependent Claim
126 words
In a pH measuring system which periodically samples the voltage output between a glass electrode and an associated reference electrode in a solution being measured, apparatus for testing the glass electrode between consecutive samples to determine if the glass membrane is cracked, comprising: means for passing a test current through said electrode combination for a period which is at least less than half the sampling period and for automatically passing another current of the same magnitude in the opposite direction for a period of the same duration as said test current; and means for measuring the voltage change between said reference and said glass electrode as a result of said test current for indicating a cracked electrode if said voltage change is below a minimum amount.
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) | 1983-02-18 | 1983-08-20 | 1984-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-18 | 1987-08-20 | 1988-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-18 | 1991-08-20 | 1992-02-19 | $7700.00 | Window Closed / Lapsed |