Bent Coriolis Mass Flowmeter Multi-Point Vibration Sensing
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Solution Overview
Problem
Generic Coriolis mass flowmeters with curved measuring tubes experience measurement errors due to inhomogeneous phase distribution caused by centrifugal forces in multi-phase media, leading to zones of different mass flow rates.
Innovation Solution
A measuring device with a pair of mirror-symmetrically arranged, oscillatable measuring tubes that excite and detect bending vibrations, utilizing two pairs of vibration sensors positioned symmetrically across the equatorial surface to determine mass flow values and correct for deviations caused by multi-phase media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If bent measuring tubes are used to achieve shorter lengths and higher sensitivity, then the device compactness and sensitivity are improved, but measurement precision deteriorates due to inhomogeneous phase distribution in multi-phase media
Solution Approach 1:
The invention divides the measurement task into multiple independent measurement points along the measuring tube. By using several measurement points distributed at different positions (including symmetric and asymmetric positions), the system segments the overall mass flow measurement into local measurements that can then be combined to achieve accurate total mass flow determination despite local inhomogeneities caused by centrifugal forces.
Solution Approach 2:
The invention transitions from single-point measurement to multi-point measurement along the longitudinal dimension of the measuring tube. By adding the dimension of spatial distribution of measurement points along the tube length, the system captures the inhomogeneous phase distribution effects and compensates for them through signal combination, thereby maintaining measurement accuracy in bent tubes.
2Device complexity
If bent measuring tubes are used to achieve shorter lengths and higher sensitivity, then device compactness is improved, but measurement precision deteriorates due to measurement errors from inhomogeneous phase distribution
Solution Approach 1:
The measurement system is segmented into multiple independent sensing locations along the bent measuring tube. Each measurement point provides local mass flow information, and the combination of these segmented measurements compensates for the inhomogeneous phase distribution effects that would otherwise cause errors in the overall measurement.
Solution Approach 2:
The invention changes the measurement parameters by using multiple measurement points with different spatial positions and orientations. By varying the parameters of measurement location and combining the signals from these different positions, the system compensates for the distorting effects of centrifugal force-induced phase separation in bent tubes.
3Device complexity
If vibration sensors are placed close to the measuring tube equatorial surface, then device compactness is improved, but measurement precision deteriorates due to insufficient detection of bending vibrations
Solution Approach 1:
The vibration detection is segmented into multiple sensor positions distributed around the measuring tube. By placing sensors at different angular positions and distances from the equatorial surface, the system captures the bending vibration pattern from multiple perspectives, enabling accurate reconstruction of the vibration signal even when individual sensors are positioned compactly.
Solution Approach 2:
The invention merges the signals from multiple vibration sensors positioned at different locations to achieve accurate bending vibration detection. By combining the information from sensors placed at various positions relative to the equatorial surface, the system compensates for the limitations of individual sensor positions and achieves precise vibration measurement in a compact arrangement.
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
The solution effectively reduces measurement errors by accurately determining mass flow rates in multi-phase media, particularly in gas-laden liquids, by calculating deviations between signals from the two pairs of vibration sensors and providing corrected mass flow values.
Implementation Method 1
at least one exciter, wherein the exciter is arranged to excite bending vibrations of the measuring tubes of the pair of measuring tubes against one another
Implementation Method 2
at least a first pair of vibration sensors, wherein the vibration sensors are arranged to detect bending vibrations of the measuring tubes of the pair of measuring tubes relative to each other
Implementation Method 3
measuring device with at least one bent measuring tube for determining a mass flow measured value of a medium according to the coriolis principle
Implementation Method 4
in multiphase media, centrifugal forces can cause an inhomogeneous distribution of the phases in the curved measuring tubes if they have different densities
Data Source
Figure 1a~1b
Figure 2a~3
AI summary
The Coriolis mass flowmeter (100) according to the invention comprises at least one measuring sensor (102) having a bent measuring tube (110, 112) which is capable of vibration and is mirror-symmetrical with respect to a measuring tube transverse plane (SXY), wherein a measuring tube centre line (MM-1, MM-2) runs in a measuring tube longitudinal plane (SYZ-1, SYZ-2) which is oriented perpendicular to the measuring tube transverse plane (SXY), wherein a measuring tube equatorial surface (ME) runs perpendicular to the measuring tube longitudinal plane (SYZ-1, SYZ-2) along the measuring tube centre line (MM-1, MM-2); at least one exciter (120) for exciting measuring tube bending vibrations, at least one first pair (140, 144) of vibration sensors for capturing the bending vibrations of the measuring tube (110, 112), which sensors are arranged in a mirror-symmetrical manner with respect to the measuring tube transverse plane (SXY); and an operating and evaluation circuit (160) for driving the exciter (120), for capturing signals from the vibration sensors (140, 144), and for determining a mass flow measured value, wherein the measuring sensor (102) has a second pair of vibration sensors (142, 146) for capturing the bending vibrations, which sensors are arranged in a mirror-symmetrical manner with respect to the measuring tube transverse plane (SXY), wherein the first pair of vibration sensors (140, 144) is separated from the second pair of vibration sensors (142, 146) by the measuring tube equatorial surface (ME).