Coriolis Flow Sensor Resonant Frequency Tracking
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Solution Overview
Problem
Coriolis flow sensors face limitations in tracking resonant frequency due to mechanical relaxation processes, requiring significant time for phase shift attenuation and affecting measurement speed and accuracy.
Innovation Solution
A vibration-type measuring device with a phase comparator and frequency generator that determines and sets the excitation frequency and phase based on the phase shift between the force and sensor signals, allowing for immediate alignment with the natural frequency, eliminating the need for waiting for mechanical oscillation damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the excitation frequency is changed to track resonant frequency, then the measurement accuracy is improved, but the mechanical relaxation processes cause time delay and phase shift attenuation
Solution Approach 1:
The patent replaces mechanical relaxation processes with electronic phase control. Instead of waiting for mechanical oscillations to dampen when changing frequency, the system uses a phase comparator and frequency generator to electronically adjust the excitation signal phase and frequency, achieving immediate alignment with the natural frequency without mechanical delay.
Solution Approach 2:
The patent implements a feedback control system where a phase comparator continuously monitors the phase shift between the excitation force and sensor signals, and a frequency generator adjusts the excitation frequency based on this feedback to maintain resonance conditions, enabling fast tracking of resonant frequency changes.
2Productivity
If the excitation frequency is adjusted to maintain resonance, then the measurement speed is improved, but the mechanical oscillation damping requires waiting time
Solution Approach 1:
The patent eliminates mechanical damping waiting time by substituting mechanical oscillation control with electronic phase and frequency adjustment. The phase comparator and frequency generator work together to immediately align the excitation signal with the natural frequency, removing the need to wait for mechanical oscillations to settle.
Solution Approach 2:
The patent applies preliminary action by proactively adjusting the excitation frequency and phase before mechanical relaxation can occur. The frequency generator predicts and sets the new frequency based on feedback from the phase comparator, ensuring resonance is achieved immediately without waiting for mechanical damping to natural frequency tracking.
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 faster tracking of resonant frequency, improving measurement speed and accuracy by directly setting the new phase and frequency, thus reducing the time required to achieve resonance conditions.
Implementation Method 1
an exciter arrangement (2) which can exerts a time-dependent, periodic force F (ω, ψF) with at least one sinusoidal, for example harmonic, component or else one non-sinusoidal, that is to say non-harmonic, component at an adjustable excitation frequency ω on a measuring tube (1), through which a medium can flow, and which thus causes the measuring tube (1) to oscillate
Implementation Method 2
Vibration-type measuring devices of the generic type are also referred to as Coriolis flow sensors. They can be used to measure the flow rate of a fluid medium flowing through the measuring tube
Implementation Method 3
a phase comparator (6) which determines a phase shift Δψ between the force F and a sensor signal or the average value of at least one first sensor signal S1 (ω, ψS1) and one second sensor signal S2 (ω, ψS2), and a frequency generator (7) which sets the excitation frequency ω and/or the phase ψF of the force F on the basis of the phase shift Δψ
Data Source
AI summary
A vibration-type measuring device includes an exciter arrangement which exerts a time-dependent force with at least one sinusoidal component at an adjustable excitation frequency on a measuring tube, through which a medium can flow, and causes the measuring tube to oscillate. The measuring device includes first and second sensors which are fitted to the measuring tube at different locations. The first and second sensors output first and second measurement signals, respectively. The measuring device includes an evaluation unit which determines a first phase shift between the first and second measurement signals and uses the determined phase shift to determine a measurement variable of the medium. The measuring device includes a phase comparator, which determines a second phase shift between the force and the average value of the first and second measurement signals, and a frequency generator which sets the excitation frequency on the basis of the second phase shift.