Thermal Mass Flow Meter with Computational Fluid Adaptation
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Solution Overview
Problem
Current thermal dispersion mass flow meters face accuracy issues due to skin resistance and stem conduction, requiring multi-point flow calibration for specific fluids and conditions, which limits their applicability and measurement accuracy across varying temperatures and pressures.
Innovation Solution
Incorporating multiple Resistance Temperature Detector (RTD) elements in the flow sensor probes, along with microprocessor-based electronics, to manage changes in gas selection, temperature, and pressure, and account for stem conduction, allowing for accurate mass flow rate measurements without fluid-specific calibration over a wide range of conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-point flow calibration is performed for specific fluids and conditions, then measurement precision is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent applies parameter changes by incorporating computational modeling that dynamically adjusts measurements based on fluid properties (density, viscosity, thermal conductivity), temperature, and pressure parameters. This allows the meter to adapt to different fluids and conditions through software-based parameter adjustment rather than physical recalibration, resolving the contradiction by maintaining high precision across varying conditions without increasing device complexity
Solution Approach 2:
The patent uses computational models that create virtual representations of the physical measurement system, allowing simulations and calculations to compensate for real-world variations. By copying the physical system's behavior through mathematical models, the invention achieves accurate measurements across different fluids without requiring actual multi-point calibration for each fluid type, thus reducing calibration complexity while maintaining precision
2Measurement precision
If multi-point flow calibration is performed for specific fluids and conditions, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent implements preliminary action through pre-programmed computational models and algorithms that are prepared in advance to handle various fluid types and conditions. When a measurement is taken, the system automatically selects and applies the appropriate pre-prepared computational approach based on detected fluid properties, eliminating the need for time-consuming on-site multi-point calibration while maintaining measurement precision
Solution Approach 2:
By using computational models that replicate the measurement system's behavior under various conditions, the patent allows accurate predictions to be made without performing actual calibration experiments for each fluid type. This virtual copying approach saves significant calibration time while preserving measurement accuracy across different fluids and operating conditions
3Adaptability or versatility
If the flow meter is designed for use with a single fluid type, then manufacturing precision requirements are reduced, but adaptability decreases
Solution Approach 1:
The patent applies universality by designing a flow meter with computational modeling capabilities that can measure multiple different fluid types using the same physical hardware. The system automatically adapts to different fluids by applying appropriate computational corrections based on detected fluid properties, eliminating the need for fluid-specific hardware configurations while maintaining measurement accuracy across diverse fluid types
Solution Approach 2:
The patent uses parameter changes to achieve fluid adaptability through software-based adjustments rather than hardware modifications. By dynamically changing computational parameters (such as thermal conductivity, density, and viscosity values) based on the detected fluid type, the system maintains manufacturing simplicity while achieving broad fluid compatibility through intelligent parameter adaptation
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
Achieves measurement accuracy of up to 1-2% of full scale over a broad range of temperatures and pressures for various fluids, enabling precise mass flow rate determination with a single surrogate gas calibration, thus improving measurement reliability and reducing errors.
Implementation Method 1
Thermal dispersion mass flow meters measure the heat convected into the boundary layer of a fluid (e.g., liquid or gas) flowing over the surface of a heated velocity sensor immersed in the flow
Implementation Method 2
Incorporating multiple Resistance Temperature Detector (RTD) elements in the flow sensor probes, along with microprocessor-based electronics, to manage changes in gas selection, temperature, and pressure, and account for stem conduction
Data Source
AI summary
Microprocessor-based thermal dispersion mass flow meters (i.e., thermal anemometers) are described that use temperature sensing elements in its flow sensor probe(s) in addition to the two elements commonly used. Such systems allow for automatically managing changes in gas selection, gas temperature, gas pressure, and outside temperature. One mass flow meter described has a flow sensor with four temperature sensing elements, wherein one pair is provided in a temperature sensor probe and another pair in a velocity sensor probe. Another variation operates without a separate temperature sensor probe and integrates all function into a single three-sensor probe. Such a device may also be used in conjunction with a one- or two-sensor temperature probe.