Electrochemical Gas Sensor Reference Electrode Isolation
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Solution Overview
Problem
Electrochemical gas sensors are sensitive to target gases entering the stack arrangement, leading to falsification of measurement results due to interference with the reference electrode.
Innovation Solution
The reference electrode is positioned in the outer area of the housing, separated from the measuring electrode, with a hydrophilic membrane arm projecting from the inner to the outer area to maintain a constant reference potential and prevent gas interference, while the measuring electrode remains inside the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reference electrode is arranged in the inner housing region together with the measuring electrode, then the device structure is simplified, but the measurement precision deteriorates due to target gas interference with the reference electrode
Solution Approach 1:
The housing is divided into an inner housing region and an outer housing region by a partition wall. The measuring electrode is arranged in the inner housing region while the reference electrode is arranged in the outer housing region, spatially separating the two electrodes to prevent gas interference with the reference electrode while maintaining a relatively simple overall structure.
Solution Approach 2:
The reference electrode is extracted from the inner housing region and placed in the outer housing region. This extraction removes the reference electrode from the potentially harmful environment where target gas can interfere, thereby protecting the reference potential from falsification while maintaining device functionality.
2Measurement precision
If the reference electrode is positioned in the outer housing region separated from the measuring electrode, then the measurement precision is improved by preventing gas interference, but the device complexity increases due to partition wall and membrane arm structure
Solution Approach 1:
The membrane arm is integrated into the partition wall structure, with the reference electrode housed within a recess in the partition wall. The membrane arm protrudes from the inner housing region through the partition wall into the outer housing region, creating a nested configuration that reduces overall structural complexity while maintaining electrode separation.
Solution Approach 2:
The membrane arm acts as an intermediary structure that connects the inner and outer housing regions while providing a gas-tight seal. It allows the reference electrode to be positioned in the outer region while maintaining a controlled interface with the inner region, preventing direct gas access to the reference electrode.
3Reliability
If the membrane arm protrudes from the inner housing region into the outer housing region, then the reference electrode is protected from target gas, but the reliability deteriorates due to potential gas leakage paths
Solution Approach 1:
The membrane arm is formed as a gas-tight barrier that protrudes through the partition wall. This flexible film structure provides a reliable gas seal between the inner and outer housing regions, preventing target gas from leaking to the reference electrode while accommodating the membrane arm's protruding configuration.
Solution Approach 2:
The partition wall with its integrated membrane arm and recess structure, which initially appears to add complexity, actually creates a gas-tight sealing system that prevents gas leakage paths. The recess in the partition wall provides a gas-tight contact surface that eliminates potential leakage points.
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
This configuration ensures a reliable reference potential and minimizes target gas interference, enhancing the measurement accuracy and stability of the electrochemical gas sensor.
Implementation Method 1
The hydrophilic membrane is configured to accommodate an aqueous electrolyte, for example, an aqueous solution containing sulfuric acid, and to be connected to the measuring electrode and the reference electrode, so that a connection between the reference electrode and the measuring electrode is achieved by means of the hydrophilic membrane and the electrolyte accommodated therein
Implementation Method 2
The hydrophilic membrane and the membrane arm are in contact with the partition wall in such a way that gas passage from the gas inlet toward the housing outer region A and in particular toward the reference electrode 40 and vice versa, is prevented
Data Source
Figure 1~4
Figure 5a~6b
Figure 7~8
AI summary
An electrochemical gas sensor is provided. The electrochemical gas sensor comprises a housing divided transversely into an inner and an outer housing compartment by a partition extending vertically along the housing. It also includes a measuring electrode, a reference electrode, and a hydrophilic membrane. The measuring electrode and the hydrophilic membrane are located in the inner housing compartment. The hydrophilic membrane has a membrane arm for receiving the reference electrode. This membrane arm projects from the inner housing compartment into the outer housing compartment, so that the reference electrode is located in the outer housing compartment.