Vibronic Mass Flow Measurement with Multi-Point Temperature Compensation
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Solution Overview
Problem
Vibronic measuring systems face significant measurement errors, particularly in fluids with low specific heat capacity and rapidly changing temperatures, leading to inaccuracies in mass flow rate measurements, especially at low Reynolds numbers and mass flow rates below 1 kg/h.
Innovation Solution
The system employs two tubes with temperature sensors positioned at different points along their lengths to account for temperature gradients, generating vibration and temperature measurement signals that compensate for phase differences caused by temperature changes, ensuring accurate mass flow rate measurement independent of temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are positioned at single points in conventional vibronic measuring systems, then the device complexity is reduced, but measurement precision deteriorates due to temperature gradients causing phase differences in rapidly changing temperature conditions
Solution Approach 1:
The temperature measurement function is segmented into multiple sensing points along the tube length. Instead of using a single temperature sensor, the patent employs multiple temperature sensors positioned at different locations to capture temperature gradients, thereby improving measurement precision without requiring a complete redesign of the sensing approach
Solution Approach 2:
The patent transitions from single-point temperature measurement to multi-point spatial temperature measurement along the tube length. By adding the spatial dimension to temperature sensing, the system captures temperature distribution and gradients, enabling compensation for phase differences caused by thermal effects
2Reliability
If conventional single-point temperature measurement is used, then the device complexity is low, but reliability deteriorates in fluids with low specific heat capacity and rapidly changing temperatures
Solution Approach 1:
The patent performs preliminary temperature measurement at multiple points along the tube before the fluid reaches the measurement section. By anticipating temperature variations and measuring them in advance at multiple locations, the system can compensate for thermal effects on mass flow measurement, improving reliability in challenging thermal conditions
Solution Approach 2:
The system uses multiple temperature sensors to continuously monitor temperature distribution and feeds this information back to compensate for thermal effects on the mass flow measurement. The temperature data from multiple points provides feedback about thermal gradients, enabling real-time correction of measurement errors
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 reduces measurement errors to less than 0.05% and 1 kg/h, maintaining high accuracy even under challenging conditions such as low specific heat capacity fluids and rapidly changing temperatures.
Implementation Method 1
a first temperature sensor (71) thermally conductively coupled to the wall (11w) of the first tube (11) and positioned less far from the first end (11a) of the first tube (11) than from the second end (11b) of the first tube (11) to sense a first measuring point temperature
Implementation Method 2
a first vibration sensor (51) for sensing mechanical vibrations of at least the first tube (11), which sensor (51) is positioned less far from the first end (11a) of the first tube (11) than from the second end (11b) of the first tube (11)
Implementation Method 3
the transducer device has at least two tubes which respectively comprise a lumen surrounded by a wall that is metallic in most cases, wherein each of the tubes, which extend from a respective inlet-side first end to a respective outlet-side second end, is designed to be flowed through at least by a partial volume of the fluid to be measured
Data Source
AI summary
A measuring system comprises a measuring and operation electronic unit (ME) and a transducer device electrically coupled thereto. The transducer device has two tubes through which a fluid flows and causes to vibrate, a vibration exciter, two vibration sensors on the inlet and outlet sides, respectively, for generating vibration signals, and an inlet-side temperature sensor coupled to a wall of the tube for thermal conduction and an outlet-side temperature sensor coupled to a wall of the tube for generating temperature measurement signals. The measuring and operation electronic unit feeds electrical power into the vibration exciter in order to effect mechanical vibrations of the tube. Furthermore, the ME generates a mass flow sequence, by means of each of the vibration signals and each of the temperature measurement signals in such a way that mass flow measurement values are independent of the temperature difference.