Ion Selective Electrode Resistance Measurement Stabilization
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Solution Overview
Problem
Conventional methods for measuring the direct-current resistance of ion selective electrodes in electrolyte concentration measuring apparatuses face inaccuracies due to parasitic capacity influences and unstable interface potentials, particularly with platinum electrodes, leading to errors in direct-current resistance measurements.
Innovation Solution
An electrolyte concentration measuring apparatus and method that includes multiple ion selective electrodes and a reference electrode, with a potential measuring unit to measure voltage and current, and a resistance measuring unit to determine direct-current resistance, stabilizing the interface potential and reducing parasitic capacity effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alternating-current measurement is used to measure resistance, then the measurement can be performed, but parasitic capacity influences cause underestimation of resistance and reduce measurement accuracy
Solution Approach 1:
The patent changes the measurement parameter from alternating-current resistance to direct-current resistance. By using direct-current voltage measurement, the parasitic capacity influence is eliminated because direct current does not cause capacitive reactance effects. The patent implements this by measuring the direct-current voltage across the ion selective electrode and calculating resistance based on the relationship between applied current and measured voltage, thereby achieving accurate resistance measurement without parasitic capacity underestimation.
2Measurement precision
If direct-current voltage measurement is performed for electrolyte concentration measurement, then concentration measurement is achieved, but direct-current resistance measurement cannot be performed simultaneously
Solution Approach 1:
The patent makes the potential measuring unit multi-functional by enabling it to perform both electrolyte concentration measurement and direct-current resistance measurement. The same potential measuring unit that measures direct-current voltage for concentration determination is also used to measure the voltage drop across the ion selective electrode when a known current is applied, allowing resistance calculation. This eliminates the need for separate measurement systems and enables both measurement types to be performed using the same hardware infrastructure.
Solution Approach 2:
The patent employs periodic switching between measurement modes. The measurement system alternates between performing electrolyte concentration measurements using direct-current voltage and performing resistance measurements by applying a known current and measuring the resulting voltage. This periodic action allows both measurement functions to be integrated into the same system without continuous interference, as each measurement type is performed in designated time intervals.
3Measurement precision
If platinum electrode is used for resistance measurement, then alternating-current measurement can be performed, but interface potential instability causes direct-current resistance measurement errors
Solution Approach 1:
The patent extracts the resistance measurement function from the context of alternating-current measurement with platinum electrodes and implements it separately using direct-current measurement. By removing the alternating-current component and the platinum electrode requirement, the patent eliminates the interface potential instability problem that plagues direct-current measurements with platinum electrodes. The resistance measurement is performed using the ion selective electrode itself with direct-current excitation, bypassing the need for stable platinum electrode interfaces.
4Measurement precision
If ion selective electrode is used regularly and replaced after certain use, then measurement accuracy is maintained, but frequent replacement increases operational complexity and cost
Solution Approach 1:
The patent performs preliminary resistance measurement on the ion selective electrode before it is fully degraded. By measuring the direct-current resistance and comparing it to reference values, the system can detect early signs of electrode degradation and prompt users to replace the electrode proactively. This preliminary detection prevents measurement accuracy degradation and reduces the need for frequent reactive replacements, thereby simplifying operational workflows and reducing downtime.
Solution Approach 2:
The patent implements a feedback mechanism where the measured resistance value is compared against predetermined thresholds or reference values. When the resistance exceeds a certain threshold indicating degradation, the system provides feedback to the user to replace the electrode. This feedback loop enables predictive maintenance, allowing users to replace electrodes based on actual condition rather than fixed schedules, thereby optimizing both measurement accuracy and operational efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables accurate measurement of direct-current resistance by stabilizing the interface potential and minimizing parasitic capacity influences, thereby improving measurement accuracy and reducing errors.
Implementation Method 1
the ion selective electrode is immersed, together with a reference electrode, in a sample solution containing an electrolyte. In this state, a potential difference between the electrodes is measured to determine the quantity of the ion to be measured in the sample
Implementation Method 2
a resistance measuring unit that measures a direct-current resistance of the plurality of ion selective electrodes
Implementation Method 3
a potential measuring unit that measures a voltage between the plurality of ion selective electrodes and the reference electrode
Data Source
AI summary
An electrolyte concentration measuring apparatus is provided with: a plurality of ion selective electrodes and one reference electrode; a sample introduction unit that introduces a sample solution to the plurality of ion selective electrodes and the reference electrode; a potential measuring unit that measures a voltage between the plurality of ion selective electrodes and the reference electrode; and a resistance measuring unit that measures a direct-current resistance of the plurality of ion selective electrodes.