Gas Flow Meter with Three-Point Temperature Sensing
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Solution Overview
Problem
Existing gas flow measurement methods using temperature sensors struggle to accurately determine gas parameters, especially for natural gases with varying compositions, as they are influenced by ambient temperature and gas mixture composition, limiting the precision of flow rate measurements to only a few gas mixtures.
Innovation Solution
A method employing three temperature sensors, including one on the heating element, to determine gas parameters by using measured temperature values to create calibration tables or weighted sums, allowing for the precise measurement of multiple gas parameters such as flow rate, thermal conductivity, and thermal diffusivity, while minimizing memory consumption in computing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two temperature sensors are used to measure flow rate, then flow rate measurement is enabled, but measurement precision deteriorates when gas composition varies
Solution Approach 1:
The patent segments the temperature measurement function by using three separate temperature sensors instead of two, with each sensor providing independent temperature data. This additional segmentation of measurement points enables the system to distinguish between temperature changes caused by flow rate versus those caused by gas composition variations, thereby resolving the contradiction between measurement capability and precision.
Solution Approach 2:
The patent adds another dimension to the measurement system by introducing a third temperature sensor, transforming the measurement from a two-point to a three-point system. This dimensional expansion creates additional degrees of freedom in the measurement space, allowing the system to independently solve for both flow rate and gas composition effects that previously confounded two-sensor systems.
2Measurement precision
If additional temperature sensors are added to determine multiple gas parameters, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the three-temperature-sensor system to perform multiple functions: it can determine flow rate, thermal conductivity, and various gas composition parameters all with the same sensor array. The heating element also serves dual purposes as both a heater and a temperature sensor, reducing the need for additional dedicated components and thereby managing device complexity while maintaining multi-parameter measurement precision.
Solution Approach 2:
The patent utilizes parameter changes by varying the heating power of the heating element and measuring temperature responses at different power levels. This dynamic parameter adjustment allows the system to extract multiple gas parameters (thermal conductivity, specific heat capacity, composition) from the same physical sensors without requiring additional hardware, thus improving measurement precision while controlling device complexity.
3Device complexity
If the heating element is used as a temperature sensor, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent applies self-service by having the heating element measure its own temperature through its electrical resistance. The heating element serves itself by utilizing its inherent electrical properties (resistance changes with temperature) to provide temperature measurement data, eliminating the need for separate temperature sensors at certain positions and thereby reducing device complexity while maintaining adequate measurement precision through the combined three-sensor system.
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 accurate determination of multiple gas parameters for a wide range of gas types, improving measurement precision and reducing the need for extensive calibration, with the ability to correct gas flow measurements based on other parameters like thermal conductivity.
Implementation Method 1
a measuring section with a heating element
Implementation Method 2
at least three temperature sensors over which the gas is guided
Implementation Method 3
As the gas flow over the temperature sensors and the heating element increases, the heated gas is transported in a directed manner from the heating element in the direction of the temperature sensor located downstream
Implementation Method 4
the computing device determines at least two separate gas parameters as a function of the measured temperature values
Data Source
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AI summary
Method for determining at least one gas parameter, in particular a flow rate, of a flowing gas, using a flow meter comprising a measuring section with a heating element and at least three temperature sensors over which the gas is passed, wherein at least one first temperature sensor is arranged upstream of the heating element, at least one second temperature sensor is located in the region of the heating element and at least one third temperature sensor is arranged downstream of the heating element, wherein in particular the heating element itself can be used as a second temperature sensor, wherein a computing device determines the at least one gas parameter as a function of the temperature measurements at the first, the second and the third temperature sensor.and/or that the computing device determines at least two separate gas parameters depending on the temperature readings of individual different temperature sensors and/or the combinations of temperature readings from different temperature sensors, wherein the temperature readings from the first, the second and the third temperature sensor are used in the determination of the gas parameters.