Coriolis Flowmeter Optical Sensor Constant Voltage Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Coriolis flowmeters using optical detection devices often suffer from accuracy issues due to parasitic capacitance and temperature-dependent time constants, leading to phase rotation and reduced measuring accuracy.
Innovation Solution
The implementation of a transimpedance amplifier with a low input impedance to maintain a constant voltage across the photosensitive sensor, reducing parasitic capacitance effects and using a differential amplifier to eliminate voltage offset, thereby improving signal quality and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high resistance value is chosen for the series resistor to maximize the voltage signal from the photosensor, then the voltage output is improved, but the time constant increases causing phase rotation and measurement error
Solution Approach 1:
The patent changes the electrical parameters of the photosensor circuit by applying a constant voltage across the photosensor using an electronic circuit (such as a voltage regulator or operational amplifier configuration). This allows the use of a low series resistance value without sacrificing signal voltage, thereby reducing the RC time constant and eliminating phase rotation while maintaining adequate signal level through active voltage stabilization rather than passive resistance scaling
Solution Approach 2:
The patent introduces an electronic voltage stabilization circuit as an intermediary between the light source and the photosensor. This intermediary circuit actively maintains a constant voltage across the photosensor, decoupling the photosensor operation from the series resistance value and allowing optimization of the time constant without compromising measurement signal quality
2Measurement precision
If the parasitic capacitance is compensated for once through calibration, then the initial accuracy is improved, but temperature drift and aging cause capacitance variation leading to measurement error
Solution Approach 1:
The patent transitions from a static calibration approach to a dynamic compensation approach by continuously applying a constant voltage across the photosensor during operation. This dynamic voltage stabilization compensates for capacitance variations caused by temperature drift and aging in real-time, maintaining measurement accuracy without requiring repeated recalibration
Solution Approach 2:
The patent implements a feedback mechanism through the electronic voltage stabilization circuit that continuously monitors and adjusts the voltage across the photosensor. This feedback loop compensates for changes in parasitic capacitance due to temperature and aging effects, maintaining consistent measurement performance over time and across varying environmental conditions
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 significantly reduces phase rotation and maximizes the resolution of the flowmeter by maintaining a constant voltage and eliminating voltage offset, enhancing the accuracy and reliability of the flow measurement.
Implementation Method 1
an optical sensor for generating a signal that is representative of the movement of the Coriolis tube, said optical sensor comprising a light source and a photosensitive sensor
Implementation Method 2
the means for applying a constant voltage across the photosensitive sensor during operation independently of the current generated by the photosensitive sensor
Implementation Method 3
a flowmeter operating by the Coriolis principle
Implementation Method 4
The light sensor acts as a photon counter, the current through the sensor being proportional to the quantity of incident light
Data Source
Figure 1A~1D
Figure 2~5
Figure 6~8
AI summary
Coriolis mass flowmeter with a Coriolis tube and with an optical detection device, which optical detection device comprises at least one optical sensor for generating a signal that is representative of the movement of the Coriolis tube, said optical sensor comprising a light source and a photosensitive sensor, wherein the optical detection device comprises means for applying a constant voltage across the photosensitive sensor during operation independently of the current generated by the photosensitive sensor in response to incident light, as well as means for determining the value of the current generated by the photosensitive sensor and converting it into an output signal.