Coriolis Flowmeter Multi-Phase Measurement Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Coriolis flowmeters face accuracy issues when measuring multi-phase flows due to fluid decoupling and increased drive gain limitations, leading to under-reported flow and density measurements in the presence of entrained gas and solids.
Innovation Solution
The flowmeter employs advanced meter electronics to differentiate between types of multi-phase flows, calculate flow rates accurately, and compensate for under-read factors by using temperature sensors, pickoff sensor signals, and algorithms to adjust for varying gas void fractions and Lockhart-Martinelli parameters, thereby improving measurement reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Coriolis flowmeter is used to measure multi-phase flows, then mass flow and density measurements can be obtained, but accuracy is degraded due to fluid decoupling and entrained gas
Solution Approach 1:
The patent changes the operational parameters by using multiple vibration modes (not just a single mode) and adjusting drive gain dynamically based on detected flow conditions. This allows the system to adapt to multi-phase flow conditions and maintain measurement accuracy despite fluid decoupling effects
Solution Approach 2:
The system continuously monitors vibration amplitude and drive gain requirements, using this feedback to detect multi-phase flow conditions. When gas void fraction exceeds a threshold or drive gain requirements indicate multi-phase conditions, the system applies correction factors to compensate for measurement errors
2Measurement precision
If drive gain is increased to compensate for diminished transducer amplitude in multi-phase flow, then measurement sensitivity is improved, but drive gain limitations cause under-reported measurements
Solution Approach 1:
The system dynamically adjusts drive gain based on real-time detection of flow conditions. By monitoring changes in vibration amplitude and the drive gain required to maintain it, the system can identify when multi-phase conditions cause amplitude diminishment and apply appropriate correction factors to prevent under-reporting
Solution Approach 2:
The patent replaces reliance on mechanical vibration amplitude alone with a computational approach that uses multiple vibration modes and algorithmic correction factors. This substitution allows the system to compensate for amplitude losses without being limited by drive gain constraints
3Reliability
If multiple vibration modes are used to improve measurement accuracy in multi-phase flows, then measurement reliability is enhanced, but device complexity increases
Solution Approach 1:
The patent makes the existing flowmeter hardware multi-functional by using it to detect multiple vibration modes and derive multiple measurement parameters (mass flow, density, gas void fraction). This universal use of the hardware reduces the need for additional specialized components while improving reliability
4Measurement precision
If correction factors are applied to compensate for under-read factors, then measurement accuracy is improved, but calculation complexity increases
Solution Approach 1:
The system performs preliminary detection of flow conditions (single-phase vs. multi-phase, gas void fraction calculation) before applying correction factors. This preliminary analysis allows the system to selectively apply corrections only when needed, reducing unnecessary computational complexity while maintaining accuracy
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 enhances the accuracy of mass flow and density measurements in multi-phase flows by ignoring unreliable data points and applying correction factors, resulting in more reliable and precise readings even in challenging flow conditions.
Implementation Method 1
the sensor assembly responds to at least mass flow rate and density of a process material flowing through the sensor assembly
Implementation Method 2
Mass flow rate may be determined by measuring time delay or phase differences between motions at the transducer locations
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for improving flowmeter (5) reliability is provided. The flowmeter (5) has at least one flow tube (130, 130'), at least one pickoff sensor (170L, 170R) attached to the flow tube (130, 130'), at least one driver (180L, 180R) attached to the flow tube (130, 130'), and meter electronics (20) in communication with the at least one pickoff sensor (170L, 170R) and driver (180L, 180R). The method includes the steps of vibrating at least one flow tube (130, 130') in a drive mode vibration with the at least one driver (180L, 180R), and receiving a sensor signal based on a vibrational response to the drive mode vibration from the at least one pickoff sensor (170L, 170R). At least one flow variable is calculated. A pickoff sensor voltage is measured, and it is determined whether the pickoff sensor voltage is below a predetermined voltage threshold (304). The at least one flow variable is corrected during periods wherein the pickoff sensor voltage is below the predetermined voltage threshold (304).