Flow Rate Measuring Device Guided Wave Frequency Optimization
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Solution Overview
Problem
Existing flow rate measuring devices using ultrasound face challenges such as difficulty in optimizing frequency due to variations in piezoelectric elements and pipes, simultaneous detection of multiple frequencies leading to beat generation, and reduced sensitivity with pipe diameter changes, affecting measurement accuracy.
Innovation Solution
Optimizing the frequency of ultrasound to match the peak of group velocities and using an amplification circuit with resonance circuits and amplifiers to reduce frequency overlap, along with a tapered flow path design to increase energy injection and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency of ultrasound transmission element is set to match a peak of group velocities, then measurement precision is improved, but it becomes difficult to maintain frequency agreement due to variations in piezoelectric elements and pipes
Solution Approach 1:
The patent changes the approach from fixing the ultrasound frequency to a specific value to dynamically determining the optimal frequency based on the actual pipe and fluid characteristics. The system measures the propagation velocity of guided waves at multiple frequencies and identifies the peak, then uses this measured peak frequency for flow velocity calculations, adapting to variations in piezoelectric elements and pipes.
2Ease of operation
If a broad frequency range is used for ultrasound transmission, then ease of operation is improved, but multiple frequencies are detected simultaneously causing beat generation and reducing measurement accuracy
Solution Approach 1:
The patent performs a preliminary measurement of the propagation velocity of guided waves across a frequency range before the actual flow velocity measurement. This preliminary action identifies the peak frequency specific to the pipe and fluid combination, which is then used as the basis for accurate flow velocity measurement, preventing beat generation from multiple frequencies.
3Ease of manufacture
If the pipe diameter is increased, then ease of manufacture is improved, but the flow velocity sensitivity decreases
Solution Approach 1:
The patent changes the measurement approach from relying on fixed theoretical models to empirically determining the propagation velocity characteristics for each specific pipe and fluid combination. By measuring the actual peak frequency and propagation velocity characteristics, the system maintains flow velocity sensitivity across different pipe diameters, overcoming the limitation of theoretical models.
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
This approach allows for precise measurement of flow velocity by isolating the frequency of guided waves, reducing multi-frequency detection, and enhancing sensitivity by increasing energy injection and reception, thereby improving measurement accuracy.
Implementation Method 1
a change in the flow velocity of the fluid affects the propagation velocity of the guided waves propagating through the pipe
Implementation Method 2
propagating ultrasound into a fluid flowing through a tube path, obtaining the velocity of the fluid from the difference between the velocity of ultrasound propagation
Implementation Method 3
obtaining the flow velocity of the fluid from the propagation time difference between a propagation time T1 and a propagation time T2
Implementation Method 4
an amplification circuit, in which a resonance circuit, an amplifier, a resonance circuit, and an amplifier are sequentially arranged
Data Source
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AI summary
[Problem] A flow rate measuring device in which guided waves are used, wherein the frequency of ultrasound is optimized; and energy injected from ultrasound transmission/reception elements is increased and the flow velocity sensitivity is raised; whereby the measurement accuracy is improved. [Solution] A frequency of an isolated peak of group velocities of guided waves, from among a plurality of peaks of group velocities of guided waves, and a resonance frequency of the ultrasound transmission element/reception element are set to agree; and the semi-amplitude of a power spectrum of ultrasound excited/received by the ultrasound transmission element/reception element is set to a value that does not overlap with another peak of group velocities.