Ultrasonic Flow Sensor for Variable-Mixture Flow Rate Measurement
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Solution Overview
Problem
Existing ultrasonic flow sensors are limited to determining flow rates for specific fluids or fluid mixtures and suffer from measurement errors when the mixture composition deviates from the assumed ratio, leading to inaccurate readings.
Innovation Solution
A flow sensor comprising a temperature module, two ultrasonic modules, and an evaluation module that determines the mixing ratio and flow rate using temperature, first and second sound transit times, and stored relationships to account for varying fluid compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ultrasonic flow sensors use a fixed table for flow rate determination, then the device complexity is reduced, but the measurement precision deteriorates when fluid composition deviates from the assumed mixture
Solution Approach 1:
The patent implements dynamic adaptation by determining the actual mixing ratio of the fluid mixture and using this information to select or adjust the appropriate flow rate table. Instead of relying on a single fixed table, the system dynamically switches between multiple tables or adjusts parameters based on the detected mixing ratio, allowing accurate measurements across varying fluid compositions without increasing hardware complexity
Solution Approach 2:
The patent changes the parameter used for flow rate determination from a fixed assumed mixing ratio to an actually detected mixing ratio. By measuring the acoustic properties of the fluid and determining the real mixing ratio, the system selects the appropriate flow rate table that corresponds to the actual fluid composition, thereby maintaining measurement precision while avoiding the need for complex additional correction mechanisms
2Measurement precision
If additional physical correction elements such as heat flux are added to correct flow rate, then the measurement precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent introduces an intermediary approach by using acoustic measurements and temperature data as intermediate parameters to determine the mixing ratio, which then serves as the basis for selecting the appropriate flow rate table. This intermediary method avoids the need for direct physical correction elements like heat flux sensors, achieving measurement precision through intelligent data processing rather than additional physical correction hardware
Solution Approach 2:
The patent replaces mechanical/physical correction systems (such as heat flux correction elements) with an acoustic-based detection and evaluation system. By using ultrasonic transit time measurements and temperature data to determine mixing ratio and select appropriate flow rate tables, the system achieves correction functionality through signal processing and algorithmic selection rather than additional physical correction components
3Manufacturing precision
If the flow sensor is designed for a specific fluid mixture, then the manufacturing precision is improved, but the adaptability deteriorates when the mixing ratio varies
Solution Approach 1:
The patent implements universality by designing the flow sensor to handle multiple fluid compositions through the use of multiple flow rate tables, each corresponding to a specific mixing ratio. The sensor universally determines the actual mixing ratio using acoustic and temperature measurements, then selects the appropriate table to provide accurate readings for that specific composition, making the device adaptable to varying fluid mixtures while maintaining precision for each composition
Solution Approach 2:
The patent enables the flow sensor to dynamically adapt to different fluid compositions by detecting the actual mixing ratio and switching between multiple pre-calibrated flow rate tables. This dynamic selection process allows the sensor to maintain manufacturing precision for each specific mixture type while providing versatility across a range of mixing ratios, eliminating the need for separate sensors for different fluid compositions
Data Source
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AI summary
The invention relates to a flow sensor (1) for determining a flow rate (Y) of a fluid which flows along a direction of flow (S) and is a mixture mixed according to a mixing ratio, wherein the flow sensor (1) has a temperature module (10) for measuring a temperature (T) of the fluid, a first ultrasonic module (11), a second ultrasonic module (12) and an evaluation module (13), wherein a measuring section (X) which runs through the fluid and runs at least proportionally in the direction of flow (S) is spanned between the first ultrasonic module (11) and the second ultrasonic module (12), wherein the first ultrasonic module (11) and the second ultrasonic module (12) are designed to determine a first sound propagation time (t1) along the measuring section (X) from the first ultrasonic module (11) to the second ultrasonic module (12) and a second sound propagation time (t2) along the measuring section (X) from the second ultrasonic module (12) to the first ultrasonic module (11), wherein the evaluation module (13) is designed to determine the mixing ratio of the fluid from the temperature (T), the first sound propagation time (t1) and the second sound propagation time (t2), wherein the evaluation module (13) is also designed to determine the flow rate (Y) from the mixing ratio, the temperature (T), the first sound propagation time (t1) and the second sound propagation time (t2).