Coriolis Flowmeter Signal Processing for Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Coriolis flowmeters face challenges in maintaining measurement precision and high filtering performance when fluid temperature changes or air bubbles are introduced, requiring complex computations and large memory consumption, which complicates the design and increases costs.
Innovation Solution
A signal processing method for Coriolis flowmeters that involves detecting phase differences and vibration frequencies proportional to the Coriolis force using velocity or acceleration sensors, with frequency conversion to stabilize measurements, allowing for constant precision and reduced computational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex computations and large memory consumption are used to maintain measurement precision under changing fluid conditions, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the sampling frequency based on the detected vibration frequency of the flow tube. When the vibration frequency changes due to fluid conditions (temperature, density, air bubbles), the sampling frequency is automatically adjusted to maintain an integer multiple relationship, thereby maintaining measurement precision without requiring complex computational algorithms or large memory resources.
2Device complexity
If the sampling frequency is not adjusted when vibration frequency changes, then device complexity is reduced, but measurement precision deteriorates under changing fluid conditions
Solution Approach 1:
The patent implements feedback control by continuously detecting the vibration frequency of the flow tube and using this information to adjust the sampling frequency. The microcomputer monitors the vibration frequency and automatically modifies the sampling frequency to maintain the integer multiple relationship, ensuring accurate phase difference measurements even when fluid conditions change, without requiring complex external control systems.
3Reliability
If high filtering performance is achieved through complex computations, then filtering performance is improved, but computational load increases
Solution Approach 1:
The patent reduces computational load by changing the sampling frequency parameter to match the vibration frequency. By maintaining the integer multiple relationship through parameter adjustment rather than complex filtering algorithms, the system achieves high filtering performance and accurate phase difference detection with minimal computational resources, enabling real-time processing even in microcomputers with limited processing power.
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
Enables constant precision and high filtering performance even with changing fluid conditions, reducing computational complexity and memory requirements, thus improving measurement stability and cost-effectiveness.
Implementation Method 1
a flow tube to be vibrated is referred to as flow tube. The Coriolis flowmeter is well known and a shape of a flow tube in the Coriolis flowmeter is broadly divided into a straight-tube type and a curved-tube-type.
Implementation Method 2
A combination of a coil and a magnet are generally used as driving means for driving the flow tube.
Implementation Method 3
a phase difference and/or a vibration frequency proportional to a Coriolis force acting on the at least one flow tube or the pair of flow tubes are/is detected by a pair of velocity sensors or a pair of acceleration sensors
Data Source
Figure 1
Figure 2
Figure 3
AI summary
[Summary] [Object] To provide a signal processing apparatus which may always perform measurement with constant precision and performs phase measurement with high filtering performance and a small amount of computation even when a temperature of a fluid to be measured changes, air bubbles are mixed into the fluid to be measured, or the fluid to be measured rapidly changes from a gas to a liquid. [Solving Means] In a Coriolis flowmeter, a vibrator is operated to vibrate at least one flow tube or a pair of flow tubes (2 and 3). A phase difference and/or a vibration frequency proportional to a Coriolis force acting on the flow tubes (2 and 3) are/is detected by vibration detection sensors to obtain a mass flow rate and/or density of the fluid to bemeasured. The Coriolis flowmeter includes a frequency measurement unit (110) for measuring a frequency based on an input signal frequency of one of the sensors, of two flow rate signals obtained by A/D conversion on detection signals from a pair of the vibration detection sensors (7 and 8), a transmitter (120) for transmitting and outputting a desired frequency signal based on the measured frequency, frequency conversion sections (130 and 140) for adding (or subtracting) detection frequencies from the pair of the vibration detection sensors (7 and 8) to (or from) an output frequency of the transmitter (120) to perform frequency conversion, and a phase difference measurement section (150) for measuring a phase difference between respective frequency signals which are detected by the pair of the vibration detection sensors (7 and 8) and obtained by conversion by the frequency conversion sections (130 and 140).