Potentiometric Sensor Glass Bulb Diagnostics Without Ground Rod
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Solution Overview
Problem
Existing potentiometric sensor assemblies require a solution ground rod for glass bulb diagnostics, adding complexity to the electrode assembly.
Innovation Solution
A potentiometric sensor assembly that performs glass bulb diagnostics without a solution ground rod, using an ion-sensing circuit to measure the impedance of the ion-sensitive glass bulb by injecting a test current and calculating the glass bulb's impedance, issuing warnings for 'broken glass' and 'out of solution' conditions based on pre-defined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solution ground rod is added to the electrode assembly for glass bulb diagnostics, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The sensor assembly performs self-diagnostics by using its own existing electrodes and circuitry to measure glass bulb impedance. The measurement electrode and reference electrode are used to apply a test current and measure the resulting voltage, allowing the system to monitor its own health without external diagnostic equipment or additional ground rods.
Solution Approach 2:
The existing electrodes serve dual purposes: the measurement electrode and reference electrode are used both for normal pH measurement and for glass bulb diagnostics. This multi-functionality eliminates the need for dedicated diagnostic components like a solution ground rod, reducing overall device complexity while maintaining diagnostic capability.
2Reliability
If impedance measurement is performed continuously, then sensor function monitoring is improved, but energy consumption increases
Solution Approach 1:
The system performs impedance measurements periodically or at specific intervals rather than continuously. The microprocessor can be configured to measure glass bulb impedance at startup, during calibration, or at scheduled intervals, reducing energy consumption while still providing adequate monitoring of sensor function throughout operation.
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
Enables reliable glass bulb diagnostics without the need for a solution ground rod, reducing complexity and improving sensor functionality by accurately detecting cracks or disconnection in the glass bulb and immersion status.
Implementation Method 1
said circuit being designed to measure the potential difference that develops in the loop between the reference and the ion-sensitive electrode
Implementation Method 2
The potential difference that develops is proportional to the deviation of the process pH from 7 pH at 25° C.
Implementation Method 3
measuring an impedance of the glass bulb in the loop between the reference electrode and the ion-sensitive electrode
Data Source
Figure 1
Figure 2
AI summary
A potentiometric sensor assembly (1) und usage of said sensor assembly comprising - an ion-sensitive electrode (2) including an ion-sensitive glass bulb (3), - a reference electrode assembly (4) including a reference electrode (5), - an ion-sensing circuit (6) having a first terminal (7) connected to the ion-sensitive electrode (2) and a second terminal (8) connected to the reference electrode (5), said circuit (6) being designed to measure the potential difference (V1) that develops in the loop between the reference and the ion-sensitive electrode (5, 2), - a digital storage unit (9) which is designed to save at least an expected range of the additional potential difference (ΔV1) characterizing healthy function of the sensor and/or a range of values of the electric impedance (Rglass) of the glass bulb (3) characterizing a healthy function of the sensor, wherein the ion-sensing circuit is further designed to a) inject a pre-defined electric test current (I1) from the ion-sensing circuit (6) into the loop comprising the reference and the ion-sensitive electrode (5, 2), b) monitor the additional potential difference (ΔV1) that develops in the loop between the reference and the ion-sensitive electrode (5, 2) in reaction to the injection of the test current (I1), c) determine if the additional potential difference (ΔV1) is within an expected range characterizing healthy function of the sensor.