Tuning Fork Level Transducer Phase Control
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Solution Overview
Problem
Conventional level transducers experience reduced accuracy due to inertia-related deformation issues during the transition from positive to negative voltage periods, leading to weaker vibrations and smaller oscillation amplitudes in the sensing voltage signal.
Innovation Solution
A level transducer with a self-modulation function that adjusts the phase of the square wave driving voltage signal, utilizing a power supply module, a tuning fork module, a sensing-phase corrector, and a controller to ensure that piezoelectric elements deform appropriately, with a phase difference of 90 degrees between the sensing and driving signals, preventing inertia interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piezoelectric driving element is driven by a square wave voltage signal, then the tuning fork can vibrate to detect material level, but during voltage transition the inertia of the expanding piezoelectric element causes delayed shrinking and reduces vibration amplitude
Solution Approach 1:
The patent applies preliminary action by introducing a phase shift between the driving voltage signal and the sensing voltage signal. The phase shift is calculated based on the detected frequency of the tuning fork vibration, allowing the piezoelectric driving element to be driven at the optimal phase angle (90 degrees) to compensate for the inertia effect and maintain maximum vibration amplitude throughout the voltage cycle.
Solution Approach 2:
The patent implements dynamics by making the phase shift angle variable rather than fixed. The control unit dynamically adjusts the phase shift angle based on the detected frequency of the tuning fork, which changes with material level and properties. This dynamic adjustment ensures optimal performance across different operating conditions.
2Measurement precision
If the piezoelectric driving element expands during positive voltage period, then deformation is generated for sensing, but the element does not shrink immediately due to inertia, causing weaker vibration
Solution Approach 1:
The patent applies preliminary action by pre-calculating the optimal phase shift angle based on the detected frequency and using it to drive the piezoelectric element. This preliminary phase adjustment ensures that the element is driven at the correct moment in its cycle to compensate for inertia and maintain consistent vibration.
Solution Approach 2:
The patent implements feedback by using the sensing voltage signal to detect the actual frequency of the tuning fork vibration, then using this frequency information to adjust the phase shift angle of the driving signal. This closed-loop feedback mechanism ensures continuous optimization of vibration amplitude and consistency.
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 level measurements by maintaining synchronized deformation and shrinking/expanding phases of the piezoelectric elements, thereby improving the reliability of the sensing results.
Implementation Method 1
the piezoelectric driving element 62 obtains the driving voltage signal VT and deforms. The tuning fork 61 vibrates with a deformation of the piezoelectric driving element 62
Implementation Method 2
A sine wave sensing voltage signal VR is produced by the piezoelectric sensing element 63 by a deformation of the piezoelectric sensing element 63
Data Source
AI summary
A level transducer has a power supply module, a tuning fork module, a sensing-phase corrector and a controller. The tuning fork module has a tuning fork, at least one piezoelectric driving element, and at least one piezoelectric sensing element. The at least one piezoelectric driving element and the at least one piezoelectric sensing element are stacked on each other, and are mounted on the tuning fork. The power supply module is electrically connected and outputs a voltage to the at least one piezoelectric driving element to deform the at least one piezoelectric driving element. The at least one piezoelectric sensing element is extruded and outputs a voltage signal. The sensing-phase corrector obtains the voltage signal and outputs a clock signal to feedback control the voltage on the at least one piezoelectric driving element to optimize a deformation frequency of each piezoelectric element.