Gas Sensor Recalibration at Limit Concentration Thresholds
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Solution Overview
Problem
Existing sensor unit calibration methods for gas mixtures are costly due to the need for expensive calibration gases and require trained personnel, and there is a need for a more efficient and cost-effective method to ensure accurate sensor data while maintaining precision, particularly for monitoring gas mixtures in compressed gas reservoirs.
Innovation Solution
A two-point calibration method for initial setup followed by a single-point recalibration, using a zero-point output and a higher concentration output to establish an initial straight line, with subsequent recalibration at the limit value concentration, allowing for efficient recalibration with reduced gas consumption and personnel involvement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-point calibration is performed using defined concentration gas mixtures, then measurement precision is improved, but calibration cost and complexity increase significantly
Solution Approach 1:
The calibration process is segmented into two distinct phases: initial calibration (requiring two-point calibration with defined concentration gas mixtures) and subsequent recalibration (requiring only single-point calibration at limit value concentration). This segmentation allows the system to achieve high measurement precision during initial setup while reducing complexity and cost for routine recalibration operations.
Solution Approach 2:
The patent applies preliminary action by performing comprehensive two-point calibration during the initial calibration phase to establish an accurate output straight line with known slope and intercept. This preliminary calibration ensures high measurement precision is achieved once, while subsequent recalibration operations can proceed with simplified single-point calibration, reducing overall process complexity.
2Measurement precision
If calibrated gas mixtures with defined concentration are used, then measurement precision is improved, but loss of substance and cost increase
Solution Approach 1:
The patent applies parameter changes by transitioning from requiring defined concentration gas mixtures during initial calibration to using only limit value concentration gas mixtures for subsequent recalibration. This parameter change in the calibration gas concentration requirement significantly reduces calibration gas consumption and cost while maintaining adequate measurement precision for monitoring applications.
Solution Approach 2:
The patent applies partial action by performing full two-point calibration initially to establish accurate sensor output characteristics, then using only partial single-point calibration at limit value concentration for routine recalibration. This partial recalibration approach reduces the quantity of calibration gas needed while maintaining sufficient measurement precision for the intended monitoring purpose.
3Measurement precision
If trained service personnel perform calibration, then measurement precision is ensured, but loss of time and operational complexity increase
Solution Approach 1:
The patent applies self-service by designing the recalibration process to be performable by operational personnel without requiring specialized training in calibration procedures. The simplified single-point recalibration at limit value concentration can be conducted during routine operations, eliminating the need for dedicated trained service personnel and reducing time loss associated with formal calibration operations.
Solution Approach 2:
The patent applies preliminary action by completing the complex two-point calibration process during initial system setup, establishing accurate sensor characteristics beforehand. This preliminary calibration ensures measurement precision is achieved initially, while subsequent recalibration can be performed by operational personnel using the simplified single-point method, reducing time requirements and operational complexity.
4Reliability
If sensor units are recalibrated frequently, then reliability is improved, but loss of time and resource consumption increase
Solution Approach 1:
The patent applies parameter changes by modifying the recalibration requirements from comprehensive two-point calibration to simplified single-point calibration at limit value concentration. This parameter change in the recalibration process maintains adequate reliability for monitoring applications while significantly reducing the time and resources required for each recalibration operation.
Solution Approach 2:
The patent applies partial action by performing only the necessary single-point calibration at limit value concentration for routine recalibration, rather than conducting full two-point calibration. This partial recalibration approach maintains sufficient reliability for ensuring sensor accuracy at critical monitoring points while improving operational efficiency by reducing recalibration time and resource consumption.
Data Source
AI summary
The present invention relates to a method for calibrating at least one sensor unit which is provided for determining a concentration of a gas in a gas mixture, wherein a limit value concentration (XG) is predetermined, comprising an initial calibration of the sensor unit at at least two concentrations (X1, X2) of the gas in a respective calibration gas mixture, at least comprising the steps of determining an initial zero point output (Y1) of the sensor unit with a first calibration gas mixture, determining a further output (Y2) of the sensor unit with a second calibration gas mixture, and forming an output straight line of the sensor unit based on the initial zero point output (Y1) and the further output (Y2), wherein the output line has an initial straight line slope (α). According to the invention, the method further comprises a recalibration at a later point in time, comprising the steps of determining a limit value output (YG′) of the sensor unit with a limit value gas mixture in which the concentration (XG) of the gas substantially corresponds to the limit value concentration (XG), and forming an updated output straight line of the sensor unit based on the limit value output (YG′) and the initial zero point output (Y1) or based on the limit value output (YG′) and the initial line slope (α).