Thermal Flow Meter Composition Adaptation
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Solution Overview
Problem
Conventional thermal flow measuring devices require precise knowledge of the chemical composition of the measured medium to accurately measure flow, leading to measurement errors when composition changes, and current methods for determining composition are costly and complex.
Innovation Solution
A method to determine the chemical composition of a multi-component medium by measuring and assigning fractions of components, allowing for partial direct or indirect measurement, with unmeasured components' fractions calculated based on the qualitative composition, ensuring the sum of fractions equals one, enabling automatic composition determination in thermal flow measuring devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional thermal flow measuring devices use fixed chemical composition data, then device complexity is reduced, but measurement precision deteriorates when composition changes
Solution Approach 1:
The patent dynamically changes the chemical composition parameters input to the thermal flow measuring device by automatically determining the actual composition of the measured medium. This allows the device to adapt to composition changes without increasing physical complexity, resolving the contradiction between fixed parameters and measurement accuracy.
Solution Approach 2:
The system performs self-service by automatically determining its own operating parameters (chemical composition) without external intervention. The control unit automatically inputs the determined composition data, eliminating the need for manual parameter adjustment while maintaining measurement precision.
2Measurement precision
If complete chemical composition is measured using conventional methods, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies partial action by determining the chemical composition of the measured medium automatically through calculation based on available data, rather than using complete conventional measurement methods. This partial determination is sufficient for thermal flow measurement purposes, reducing device complexity while maintaining necessary precision.
Solution Approach 2:
The patent replaces mechanical/physical measurement systems (multiple sensors, analyzers) with a calculation-based approach. The control unit calculates composition parameters from available data, substituting complex physical measurement infrastructure with computational methods.
3Measurement precision
If chemical composition is determined continuously, then measurement precision is maintained, but use of energy and device complexity increase
Solution Approach 1:
The patent creates a computational model (copy) of the chemical composition rather than physically measuring all components. The control unit calculates composition parameters based on thermal measurement data and mass balance equations, energy-efficiently replicating composition information without extensive physical sensing.
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 cost-effective and accurate determination of chemical composition, reducing measurement errors and allowing for continuous monitoring of flow through pipelines, even with variable medium composition, by using a thermal mass flow measuring device with two temperature sensors and a control/evaluation unit.
Implementation Method 1
One of the two temperature sensors is a so-called active temperature sensor, which is heated by means of a heating unit. As heating unit, either an additional resistance heating unit is provided, or the temperature sensor is a resistance element, e.g. an RTD (Resistance Temperature Device) sensor, which is heated by conversion of an electrical power
Implementation Method 2
The two temperature sensors are usually installed in a measuring tube; the temperature sensors can, however, also be mounted directly in the pipeline. One of the two temperature sensors is a so-called active temperature sensor, which is heated by means of a heating unit
Implementation Method 3
In the case of thermal dispersion, a heated measuring element is exposed to the flow of the measured medium. The cooling rate caused thereby is a measure for the flow velocity
Data Source
AI summary
Method and thermal, flow measuring device for determining at least one variable dependent on at least the chemical composition of a measured medium, wherein the measured medium has n components, wherein n is greater than or equal to two, wherein each mole fraction, volume fraction and/or mass fraction of m components of the medium is measured, wherein m is smaller than or equal to n minus one, wherein the mole fractions, volume fractions and/or mass fractions of the k components of the measured medium which are not measured, and wherein k is equal to n minus m, are established in such a manner, that the sum of the mole fractions, volume fractions and/or mass fractions of the n components amounts to one.