Acoustic Flow Meter Temperature Compensation via Electric Network
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Solution Overview
Problem
Fluid flow measurement devices face challenges in maintaining accuracy across varying environmental conditions, particularly temperature changes, which affect the sensitivity and amplitude of signals propagated through the device, leading to reduced measurement precision.
Innovation Solution
The device incorporates an acoustic resonance cavity with temperature-compensating capacitors and electric networks featuring inductive and capacitive components, which preferentially amplify signals within specific frequency ranges, minimizing amplitude variations across the operating temperature range, and includes damping means to adjust signal amplification at resonance frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the device operates across a wide temperature range, then environmental adaptability is improved, but signal amplitude variations increase leading to reduced measurement precision
Solution Approach 1:
The patent applies parameter changes by introducing temperature-dependent capacitive elements that modify the electrical network's impedance characteristics across different temperatures. This compensates for the transducer sensitivity variations caused by temperature changes, maintaining consistent signal amplitude and measurement precision across the operating temperature range.
Solution Approach 2:
The patent uses an intermediary electrical network containing capacitive and inductive elements as a mediator between the acoustic transducers and the measurement system. This intermediary network compensates for temperature-induced sensitivity changes by adjusting signal amplification, thereby protecting the measurement precision from environmental temperature variations.
2Reliability
If transducer sensitivity varies significantly across temperature range, then environmental robustness is improved, but signal amplitude stability deteriorates
Solution Approach 1:
The patent employs parameter changes by using temperature-dependent capacitive elements whose capacitance values vary with temperature to counteract transducer sensitivity drift. This dynamic parameter adjustment maintains stable signal amplitude across the full operating temperature range, ensuring both reliability and stability.
Solution Approach 2:
The electrical network with temperature-dependent capacitive elements acts as a feedback mechanism that automatically adjusts signal amplification based on temperature conditions. This feedback loop compensates for transducer sensitivity variations, maintaining stable signal amplitude without external intervention.
3Adaptability or versatility
If the frequency response of transducers varies over operating frequency range, then operational flexibility is improved, but measurement accuracy deteriorates due to sensitivity variations
Solution Approach 1:
The patent applies parameter changes by designing the electrical network with frequency-dependent impedance characteristics that compensate for transducer sensitivity variations across the operating frequency range. This ensures consistent measurement accuracy regardless of frequency changes.
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 configuration reduces signal amplitude variations to less than 3dB, maintaining high sensitivity and accuracy despite significant transducer sensitivity variations, and allows the device to adapt rapidly to temperature changes, ensuring precise fluid flow speed measurements.
Implementation Method 1
The cavity is capable of supporting an acoustic standing wave, wherein the frequency of the supported standing wave varies with the temperature of the fluid
Implementation Method 2
the frequency of the supported standing wave varies with the temperature of the fluid over the operating temperature range
Implementation Method 3
The at least one inductive and at least one capacitive component define, together with the connected transducer, a resonance behaviour in which signals in a part of the operating frequency range are preferentially amplified
Implementation Method 4
at least two acoustic transducers, respectively for generating and detecting the acoustic standing wave
Data Source
Figure 1~2B
Figure 3~4
Figure 5~6
AI summary
There is provided a device comprising an acoustic resonance cavity through which a fluid can flow. The fluid has a temperature within an operating temperature range. The cavity is capable of supporting an acoustic standing wave. The frequency of the supported standing wave varies with the temperature of the fluid over the operating temperature range and thereby defines an operating frequency range. The device also comprises at least two acoustic transducers, respectively for generating and detecting the acoustic standing wave. A frequency response of the transducers varies over the frequency range. Connected to each transducer is an electric network comprising at least one inductive and at least one capacitive component. The at least one inductive and at least one capacitive component define, together with the connected transducer, a resonance behaviour in which signals in a part of the operating frequency range in which the transducer has a first sensitivity are preferentially amplified relative to signals in a part of the operating frequency range in which the transducer has a second sensitivity. The first sensitivity is lower than the second sensitivity. Variations in the amplitude of signals propagated through the resonance cavity, the two acoustic transducers and the connected electric networks across the operating range are less than variations in amplitude of a signal propagated through only the resonance cavity and the two acoustic transducers.