Coriolis Flowmeter Multi-Phase Detection via Amplitude Variation
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Solution Overview
Problem
Coriolis mass flowmeters face substantial measurement inaccuracies in multi-phase flow conditions, making it challenging to reliably detect the presence of multi-phase flows.
Innovation Solution
The method involves exciting the measuring tube to oscillations with different amplitudes at a constant frequency, using the control and evaluation unit to detect state variables dependent on amplitude, and determining deviations between measured values to indicate the presence of multi-phase flow, allowing for reliable detection without requiring constructional changes to the existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measuring tube is excited with a single amplitude, then the device complexity is low, but the measurement precision deteriorates in multi-phase flow
Solution Approach 1:
The patent applies periodic action by exciting the measuring tube with oscillations of different amplitudes at predetermined time intervals. The control and evaluation unit alternates between first oscillations with a first amplitude and second oscillations with a second amplitude, enabling multi-phase flow detection through periodic variation of excitation parameters without requiring additional hardware.
Solution Approach 2:
The patent implements parameter changes by varying the amplitude parameter of the excitation oscillations while maintaining a predetermined excitation frequency. The control and evaluation unit changes the amplitude from a first amplitude to a second amplitude at specific time intervals, allowing detection of multi-phase flow conditions through amplitude-dependent state variable deviations.
2Reliability
If multiple amplitudes are used for detection, then the reliability of multi-phase flow detection improves, but the loss of time increases due to multiple measurements
Solution Approach 1:
The patent uses periodic action to alternate between different amplitude excitations at predetermined intervals, allowing the system to gather multiple measurement points for reliability while maintaining a structured time sequence that minimizes total measurement time through efficient oscillation cycles.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining oscillation excitation throughout the measurement process, switching between different amplitudes without stopping the measurement cycle. This continuous oscillation allows the system to accumulate measurement data for reliability assessment without idle time between measurements.
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 enables accurate detection of multi-phase flows with minimal additional effort, differentiating between single-phase and multi-phase conditions, and determining the number of phases present, thereby improving measurement reliability and accuracy.
Implementation Method 1
the measuring tube is excited by the oscillation generator to an oscillation with a predetermined excitation frequency and a first amplitude
Implementation Method 2
the resulting oscillation of the measuring tube is detected by at least one oscillation sensor
Implementation Method 3
the Coriolis inertial force caused by the medium having mass reacts on the walls of the measuring tube due to two orthogonal velocities—the flow and the measuring tube—
Data Source
AI summary
A method for operating a Coriolis mass flowmeter in which a simple and reliable detection of a multi-phase flow is implemented by determining at least one first measured value for at least one state variable that is dependent on the amplitude in a multi-phase medium, exciting the measuring tube with the oscillation generator to oscillate at a predetermined oscillation frequency and a first amplitude, and to oscillate with the excitation frequency and a second amplitude, detecting the resulting oscillation of the measuring tube and determining at least a second measured value for the state variable that is dependent on the amplitude in a multi-phase medium from the determined resulting oscillation, and using the deviation of at least one of the first measured value from at least a corresponding second value as an indicator for the presence of a multi-phase flow.