Coriolis Flow Meter Damping Compensation for Two-Phase Media
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Solution Overview
Problem
Conventional in-line measuring devices for flow rates and densities, especially those using vibration-type sensors, face significant inaccuracies and reduced reproducibility due to inhomogeneities like gas bubbles and solid particles in two-phase or multi-phase media, leading to fluctuations in measurement accuracy and zero point shifts.
Innovation Solution
An in-line measuring device with a vibration-type transducer that performs symmetrical and anti-symmetrical flexural vibrations, coupled with electronics that determine damping values to correct for the effects of inhomogeneities, ensuring accurate mass flow and density measurements by accounting for spatial distributions of inhomogeneities and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vibration-type measuring transducer is used to measure mass flow rate and density, then high measurement accuracy is achieved under normal conditions, but measurement accuracy and zero point stability deteriorate significantly when inhomogeneities (gas bubbles, solid particles) are present in the medium
Solution Approach 1:
The patent segments the vibration measurement into two independent components: useful mode vibration (for mass flow measurement) and Coriolis mode vibration (affected by inhomogeneities). By separating these modes and measuring them independently, the system can identify and compensate for the effects of inhomogeneities on the Coriolis mode without affecting the useful mode measurement, thus resolving the contradiction between high measurement accuracy and reliability with inhomogeneities
Solution Approach 2:
The patent implements a feedback mechanism where the Coriolis mode vibration signal is continuously monitored and used to calculate compensation factors. These compensation factors are then fed back to correct the mass flow rate measurement in real-time, eliminating the negative impact of inhomogeneities and maintaining both measurement accuracy and reliability
2Productivity
If the measuring transducer operates in batch mode with short filling times, then productivity is improved, but measurement accuracy deteriorates due to insufficient vibration stabilization and flow rate fluctuations
Solution Approach 1:
The patent applies preliminary action by pre-exciting the measuring tube to vibration before the actual measurement begins. This ensures that the tube is already in a stable vibrational state when the batch filling starts, eliminating the need for long stabilization periods and allowing accurate measurements even with short filling times, thus resolving the contradiction between productivity and measurement precision
Solution Approach 2:
The patent uses periodic vibration excitation at the natural resonant frequency of the measuring tube to maintain stable oscillations throughout the batch filling process. This periodic action ensures consistent measurement conditions despite flow rate fluctuations, enabling both high productivity and accurate measurement in short filling cycles
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 significantly improves measurement accuracy and reproducibility by compensating for asymmetric damping caused by inhomogeneities, providing precise and robust control for filling processes even with two-phase or multi-phase media.
Implementation Method 1
In the flowing medium reaction forces, such as Coriolis forces, acceleration forces, frictional forces or the like, induce and derived from these at least one measurement signal
Implementation Method 2
an exciter arrangement for generating vibrations, in particular flexural vibrations, of the at least one measuring tube
Data Source
Figure 1a~3b
Figure 2
Figure 4
AI summary
The invention relates to a in-line measuring device, designed in particular as a Coriolis mass-flow/density measuring device and Coriolis mass-flow/viscosity measuring device, comprising a probe (10) of the vibrating type with at least one vibrating tube (110) which vibrates when in operation for the at least temporary guidance of a two or multi phase free-flowing medium, with an energiser arrangement (116) acting on the measuring tube to generate vibrations in the at least one measuring tube (110) and a sensor arrangement (117, 118) for recording vibrations of the at least one measuring tube, giving a vibration measured signal (S1, S2) representing the vibrations of the measuring tube. The in-line measuring device further comprises a measuring device electronic circuit (20) electrically coupled to the probe, which at least temporarily provides an energiser signal (iexc) driving the energiser arrangement, such that at least one measuring tube is energised in operation by the energiser arrangement controlled by the at least one energiser signal to at least temporarily give vibrations in a use mode for the probe, in which at least components of flexural vibrations about an imaginary flexural axis of the probe occur, essentially parallel to an imaginary longitudinal axis of the measuring tube joining the inlet end of the measuring tube to the outlet end of the measuring tube or is coincident therewith and the at least one measuring tube vibrating in use mode, vibrates under the influence of Coriolis forces induced in the flowing medium in at least temporarily in a Coriolis mode overlaid on the use mode in which at least components of flexural vibrations occur anti-symmetrically with relation to an imaginary mid-plane coplanar to a cross-section of the measuring tube, about the imaginary flexural vibrational axis of the probe. Furthermore, the measuring device electronic circuit at least temporarily determines a first type of damping value (XDI), representing an instantaneous damping of vibrations of the at least one measuring tube counteracting the flexural vibrations corresponding to the Coriolis mode.