Coriolis Flowmeter Air Bubble Detection via Harmonic Signal Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Coriolis flowmeters face challenges in accurately detecting air bubbles in fluids under varying pressure conditions, leading to fluctuations in drive gain and incorrect detection of air bubble presence or absence.
Innovation Solution
The implementation of a Coriolis flowmeter with a fluctuation calculation section, average calculation section, and determination section that processes displacement signals to calculate fluctuations and determine the state of air bubbles, using reference signals and low-pass filters to isolate low-frequency fluctuations caused by air bubbles, regardless of pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If drive gain is increased to maintain vibration amplitude under high pressure, then vibration stability is improved, but air bubble detection accuracy deteriorates due to drive gain fluctuations
Solution Approach 1:
The patent segments the detection signal processing into multiple components: extracting fundamental vibration signals, identifying harmonic components, and separately analyzing drive gain fluctuations. By dividing the signal spectrum into fundamental frequency and harmonic frequency ranges, the system can distinguish between normal vibration variations and air bubble-induced fluctuations, thereby maintaining vibration stability while improving detection accuracy.
Solution Approach 2:
The patent introduces harmonic frequency components as an intermediary indicator for air bubble detection. Instead of directly monitoring drive gain fluctuations which are confounded by pressure changes, the system uses harmonic components generated by air bubbles as a mediator signal. These harmonic components appear only when air bubbles are present, providing a reliable detection mechanism that is independent of drive gain adjustments.
2Measurement precision
If drive gain threshold is set to detect air bubbles, then air bubble detection capability is improved, but false detection increases due to drive gain fluctuations under varying pressure
Solution Approach 1:
The patent implements dynamic threshold adjustment based on real-time analysis of harmonic frequency components. Rather than using a fixed drive gain threshold that becomes unreliable under varying pressure conditions, the system dynamically adapts the detection threshold according to the presence and magnitude of harmonic components. This dynamic approach maintains high detection capability while reducing false positives caused by pressure-induced drive gain fluctuations.
Solution Approach 2:
The system continuously monitors harmonic frequency components and uses this information as feedback to adjust air bubble detection decisions. By establishing a feedback loop that correlates harmonic component levels with detection outcomes, the system can distinguish between legitimate air bubble signals and spurious drive gain variations, thereby improving both detection capability and reliability.
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 solution enables accurate detection of air bubbles in fluids, reducing false positives and negatives by isolating low-frequency fluctuations, thus ensuring reliable air bubble diagnostics across different pressure levels.
Implementation Method 1
a measurement tube (1) that enables flow of a fluid subject to measurement
Implementation Method 2
Coriolis flowmeter that determines a state of air bubbles in a fluid subject to measurement
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A Coriolis flowmeter (10) vibrates a measurement tube through which a fluid subject to measurement flows, detects vibrations including Coriolis force developed in the fluid from the vibrations, and measures a mass flow rate of the fluid from a detection signal. The Coriolis flowmeter is characterized by including fluctuation calculation section (50) that calculates fluctuations from a detection signal (SA); status value calculation section (60) that calculates a status value showing a state of air bubbles in the fluid from the fluctuations calculated by the fluctuation calculation section (50), and determination section (70) that determines a state of air bubbles from the status value calculated by the status value calculation section (60).