Thermal Model for Mass Flow Controller Rate of Decay Error Correction
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Solution Overview
Problem
Current mass flow controllers and meters face inaccuracies in rate of decay measurements due to thermally induced errors, which are difficult to correct without extensive calibration and precise temperature sensing.
Innovation Solution
A thermal model is implemented to minimize thermally induced errors in rate of decay measurements by using a processor to determine and adjust for a fit term (K1) proportional to the mass flow, allowing for real-time correction and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rate of decay measurements are performed in mass flow controllers, then mass flow calibration is achieved, but thermally induced errors reduce measurement accuracy
Solution Approach 1:
A thermal model is introduced as an intermediary computational framework that processes pressure decay data to separate and eliminate thermal effects from the measurement. The model uses a fit term (K1) that accounts for thermal transients, allowing the system to calculate corrected mass flow rates that are independent of thermal interference.
Solution Approach 2:
The system changes the parameter being measured from raw pressure decay to a corrected fit term (K1) that has been mathematically adjusted to remove thermal influences. By transforming the measurement parameter through the thermal model, the system achieves accuracy independent of thermal conditions.
2Measurement precision
If traditional calibration methods are used, then mass flow measurement is obtained, but extensive calibration and precise temperature sensing are required
Solution Approach 1:
The mass flow controller performs self-calibration by using its own pressure sensing capabilities to execute rate of decay measurements and apply thermal model corrections. The system serves its own calibration needs without requiring external calibration equipment or complex temperature sensing infrastructure.
Solution Approach 2:
The invention extracts the thermal error component from the measurement through mathematical modeling, separating the thermal effect from the mass flow signal. This extraction eliminates the need for physical temperature sensors and complex calibration procedures, as the thermal influence is removed computationally.
3Ease of operation
If rate of decay measurements are performed without thermal correction, then measurement process is simple, but measurement accuracy deteriorates over time
Solution Approach 1:
The thermal model is pre-configured with the appropriate fit term (K1) that encapsulates thermal behavior characteristics. By preparing the correction model in advance and integrating it into the measurement process, the system automatically compensates for thermal effects without adding operational complexity or requiring manual intervention.
Data Source
AI summary
The disclosed embodiments include a method, apparatus, and computer program product for improving the accuracy of a rate of decay measurement for real time correction in a mass flow controller or mass flow meter by using a thermal model to minimize thermally induced error in the rate of decay measurement.