Gas Sensor Self-Testing via Pulsed Test Gas Injection
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Solution Overview
Problem
Existing gas-measuring systems face challenges in continuously testing gas sensors without disassembly, especially in industrial settings, where power supply and data network integration are complex, and there is a need to monitor sensor operation and detect changes in operating properties.
Innovation Solution
A method using a test gas source and a pumping device within the gas-measuring system to test gas sensors by altering gas flow and measuring responses, allowing for continuous operation and integration of data analysis, with a control unit coordinating operating states to assess sensor readiness and detect malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas sensors are tested by removing or disassembling them at the measurement location, then testing can be performed, but the complexity of operation increases and continuous monitoring is interrupted
Solution Approach 1:
The gas sensor performs self-testing by receiving test gas through its own measurement channel. The control unit automatically introduces test gas and evaluates the sensor's response without requiring manual disassembly or external testing equipment, enabling the sensor to monitor its own operational status.
Solution Approach 2:
The measurement channel is designed to serve dual purposes: it functions as both the operational measurement path for detecting process gas and the testing path for introducing test gas. This multi-functionality eliminates the need for separate testing infrastructure and simplifies the overall system operation.
2Reliability
If gas sensors are continuously monitored during operation, then reliability improves, but the system complexity increases due to additional testing infrastructure
Solution Approach 1:
The existing measurement channel and gas pathway are utilized for both normal measurement operations and sensor testing. The control unit manages both functions by selectively introducing process gas or test gas through the same channel, thereby avoiding additional hardware complexity while enabling continuous monitoring.
Solution Approach 2:
The control unit acts as an intermediary that coordinates between the test gas source, the measurement channel, and the gas sensor. It automatically manages the timing and flow of test gas introduction, eliminating the need for manual intervention or complex external testing equipment.
3Measurement precision
If test gas is introduced continuously to the gas sensor, then sensor response can be monitored, but the sensor may become saturated and lose sensitivity
Solution Approach 1:
Test gas is introduced to the sensor in periodic pulses rather than continuously. The control unit manages timed intervals of test gas introduction followed by periods where normal measurement gas flows through the channel, allowing the sensor to recover and maintain sensitivity while still enabling regular monitoring of sensor response.
Solution Approach 2:
Instead of continuous test gas introduction, only partial amounts of test gas are introduced at specific intervals. This partial action is sufficient to elicit a measurable sensor response for monitoring purposes without causing saturation or permanent sensitivity loss.
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 continuous testing of gas sensors during operation, improving the reliability of gas-measuring systems by detecting changes and malfunctions, and facilitating centralized data analysis for maintenance.
Implementation Method 1
a pumping device (9) for feeding gas to be analyzed (gas to be measured) from a measuring environment (39) to the gas sensor (5)
Implementation Method 2
the gas being fed to the gas sensor (5) is detected by the gas sensor (5) by measurement
Data Source
AI summary
A method for testing a gas sensor is based on a gas-measuring system with a test gas source and with a pumping device. A predefined quantity of a gas or of a gas mixture is fed in, from the test gas source, to the gas sensor over a predefined time and metered. The response of a measured signal of the gas sensor is determined as a sensor response. Characteristic variables, from which an indicator of the ability of the gas sensor to operate is determined, are determined from the sensor response.