Ultrasonic Flow Rate Measurement Dew Condensation Compensation
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Solution Overview
Problem
Existing flow rate measurement devices using ultrasonic waves face accuracy degradation when dew condensation occurs, causing water droplets to adhere to the reflection surface, leading to erroneous detection of zero-cross points and waveform changes.
Innovation Solution
The device adjusts the reference voltage based on changes in amplification rate and measured flow rates, ensuring stable detection of zero-cross points by periodically recalculating the reference voltage when water droplet adhesion is detected, using a pair of ultrasonic wave oscillators to transmit and receive signals reflected within the flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic waves are transmitted through the flow path to measure flow rate, then flow rate measurement is enabled, but measurement accuracy degrades when dew condensation occurs and water droplets adhere to the reflection surface
Solution Approach 1:
The patent changes the reference voltage parameter dynamically based on amplification rate changes. When dew condensation is detected (through amplification rate monitoring), the reference voltage is recalculated and adjusted to compensate for the waveform changes caused by water droplet adhesion, thereby maintaining measurement accuracy despite the adverse environmental condition
Solution Approach 2:
The system implements feedback by continuously monitoring the amplification rate of received ultrasonic signals. When the amplification rate changes beyond a threshold (indicating dew condensation), the system triggers reference voltage recalculation and adjustment, creating a closed-loop control that maintains measurement reliability under varying environmental conditions
2Device complexity
If the reference voltage is kept constant to simplify the circuit, then circuit complexity is reduced, but zero-cross point detection becomes erroneous when water droplets adhere to the reflection surface causing waveform changes
Solution Approach 1:
The patent transitions from a static reference voltage to a dynamic reference voltage that can be adjusted based on operating conditions. The reference voltage setting unit recalculates and updates the reference voltage when amplification rate changes indicate dew condensation, allowing the system to adapt to waveform changes without increasing overall device complexity
Solution Approach 2:
The reference voltage parameter is changed dynamically in response to detected amplification rate changes. This parameter adjustment compensates for waveform distortions caused by water droplet adhesion, maintaining zero-cross point detection accuracy without requiring complex hardware modifications
3Stability of the object's composition
If the amplification rate is adjusted to maintain signal amplitude within voltage range, then signal reception stability is improved, but reference voltage becomes mismatched when amplification rate changes due to dew condensation
Solution Approach 1:
The system uses feedback from amplification rate monitoring to trigger reference voltage adjustments. When amplification rate changes indicate dew condensation, the reference voltage is recalculated to match the new signal characteristics, ensuring both signal stability and accurate zero-cross point detection
Solution Approach 2:
The system performs self-adjustment by automatically detecting amplification rate changes and triggering reference voltage recalculation without external intervention. This self-service mechanism ensures the reference voltage remains matched to the actual signal conditions despite environmental 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 approach stabilizes the measurement of zero-cross points and prevents degradation of measurement accuracy even when water droplets adhere to the reflection surface, ensuring accurate flow rate calculations.
Implementation Method 1
first ultrasonic wave oscillator 122 and second ultrasonic wave oscillator 123 installed in flow path 121 through which a fluid flows
Implementation Method 2
time measuring unit 129 that measures a propagation time of transmission and reception of the ultrasonic waves
Implementation Method 3
amplifier 126 that amplifies a received signal which is received by an ultrasonic wave oscillator
Implementation Method 4
reference comparator 127 for comparing a voltage of the received signal amplified by amplifier 126 with a reference voltage
Data Source
AI summary
Flow rate measurement is performed with a propagation time by using a pair of ultrasonic wave oscillators which is provided in flow path through which a fluid to be measured flows, and is disposed so as to transmit and receive an ultrasonic wave signal by causing the ultrasonic wave signal to be reflected on an inner wall of flow path at least once. In addition, adjustment of an amplification rate is periodically performed by amplifier, which amplifies the ultrasonic wave signal received by each of the ultrasonic wave oscillators to a predetermined amplitude, and a difference between a previous amplification rate and a current amplification rate is a predetermined value or more, and the instantaneous flow rate calculated by flow rate calculation unit is a predetermined flow rate or less, the reference voltage is adjusted by reference voltage setting unit. With the configuration, the propagation time can be stably measured and deterioration of the maximum amplitude is prevented.