Coriolis Mass Flow Meter Optical Sensor Temperature Compensation
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Solution Overview
Problem
Conventional Coriolis-effect mass flow meters face accuracy issues due to temperature instability affecting optical sensors and light sources, which are not adequately compensated by existing techniques, especially in low-power, space-limited devices.
Innovation Solution
The implementation of a third optical sensor not engaged with the vibrating tube, connected in series with other light sources, under closed-loop control to stabilize light intensity and compensate for temperature variations, ensuring consistent output across optical sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional temperature compensation techniques are used, then some temperature stability is achieved, but measurement precision deteriorates due to inadequate compensation and nonlinearity
Solution Approach 1:
The patent implements a closed-loop feedback control system where a third optical sensor monitors the light source output, and the system automatically adjusts the light source drive current to maintain constant light intensity despite temperature variations. This feedback mechanism continuously compensates for temperature effects, resolving the contradiction between temperature stability and measurement precision.
Solution Approach 2:
The patent dynamically adjusts the drive current parameter to the light source based on temperature conditions and monitored light output. By changing the electrical parameter (current) in response to temperature variations, the system maintains optimal light intensity for measurement accuracy while operating across a range of temperatures.
2Reliability
If additional compensation components are added, then temperature compensation improves, but device complexity increases
Solution Approach 1:
The third optical sensor serves multiple functions: it monitors light source output for temperature compensation, provides feedback for closed-loop control, and enables automatic adjustment of light intensity. This multi-functional approach improves compensation effectiveness without proportionally increasing device complexity, as one component performs several critical roles.
Solution Approach 2:
The system uses its own optical sensor to monitor and compensate for light source variations caused by temperature. The flow meter system self-regulates by using its measurement components to detect and correct their own performance degradation, eliminating the need for external compensation devices and reducing overall system complexity.
3Temperature
If constant temperature operation is implemented, then temperature stability improves, but power consumption increases
Solution Approach 1:
The patent replaces mechanical/thermal temperature control systems (heaters, coolers, thermal chambers) with an optical-electrical compensation system. Instead of physically maintaining constant temperature through energy-intensive thermal management, the system uses optical sensors and electrical current adjustment to compensate for temperature effects, dramatically reducing power consumption while maintaining measurement accuracy.
Solution Approach 2:
The system changes the operational parameter from thermal control (maintaining constant temperature through heating/cooling) to electrical/optical control (adjusting light source current to maintain constant light output). This parameter substitution eliminates the need for high-power thermal management systems while achieving the same goal of temperature compensation.
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 enhances the metrological characteristics and precision of Coriolis-effect flow meters by stabilizing light intensity and reducing measurement errors caused by temperature fluctuations.
Implementation Method 1
Each optical sensor, such as a photodiode or a phototransistor, involves a light source, such as a light emitting diode (LED)
Implementation Method 2
a light source, such as a light emitting diode (LED)
Implementation Method 3
Coriolis effect-based mass flow meters measure mass flow of media by determining a phase difference between different portions of a flow tube
Data Source
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AI summary
An example optical measurement system includes: a first light source configured to emit a first light beam; a first optical sensor configured to output first measurements based on detecting the first light beam; a second light source configured to emit a second light beam; a second optical sensor configured to output second measurements based on detecting the second light beam, wherein the first measurements and the second measurements comprise variable components; a third optical sensor configured to output third measurements based on detecting the second light beam or a third light beam, wherein the third measurements comprise a first steady state component; and a compensation circuit configured to control a first light output of the first light beam and a second light output of the second light beam by controlling current to the first light source and the second light source based on the third measurements.