Flow Meter Calibration at Variable Temperatures
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Solution Overview
Problem
Conventional flow meter calibration methods fail to account for physical effects at higher temperatures, leading to measurement errors and uncertainties due to gas bubble mixing and viscosity changes, rendering flow meters unreliable at elevated temperatures.
Innovation Solution
A method and device for calibrating flow meters over a wide temperature range by heating the fluid medium to a preset temperature, using a reference flow meter to compare measurements with a calibrated flow meter under isothermal conditions, and employing sensors to monitor pressure, temperature, and viscosity, with a calibration device that includes a heat exchanger, temperature control, and weighing mechanisms to determine accurate flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration methods are used at 40°C, then calibration simplicity is maintained, but measurement precision deteriorates at higher temperatures due to unaccounted physical effects
Solution Approach 1:
The calibration method changes the temperature parameter from a fixed 40°C to a variable range (e.g., 20°C to 100°C), allowing calibration at the actual operating temperature of the flow meter. This resolves the contradiction by enabling accurate measurements at high temperatures without requiring complex temperature compensation mechanisms, as the calibration is performed under representative operating conditions.
Solution Approach 2:
The system performs preliminary heating of the fluid medium to the desired calibration temperature before conducting the calibration measurement. This preliminary action ensures that the calibration is performed under the actual operating temperature conditions, eliminating temperature-induced measurement errors without requiring complex real-time temperature compensation during measurement.
2Measurement precision
If temperature compensation mechanisms are added to conventional calibration systems, then measurement precision at high temperatures improves, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical temperature compensation mechanisms with a simpler thermal field approach. Instead of using mechanical components to compensate for temperature effects, the system uses a heating element and temperature sensor to directly control and measure the fluid temperature, substituting mechanical complexity with thermal field control that achieves the same measurement accuracy.
Solution Approach 2:
The fluid medium itself serves as an intermediary that transfers thermal energy from the heating element to the flow meter. This intermediary approach allows temperature control without direct thermal contact between the heating element and the flow meter, simplifying the overall device structure while maintaining measurement precision through controlled thermal conditions.
3Adaptability or versatility
If calibration is performed in the 'cold' state with heated fluid only in the test section, then adaptability to changing temperatures improves, but measurement precision decreases due to non-isothermal conditions
Solution Approach 1:
The calibration system is segmented into two independent temperature control zones: a cold reference measuring section and a hot test measuring section. Each section can be independently temperature-controlled, allowing the reference flow meter to operate at a stable reference temperature while the test flow meter operates at the desired calibration temperature. This segmentation enables both adaptability to different temperatures and high measurement precision by eliminating thermal gradients between reference and test measurements.
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 high-precision calibration of flow meters across varying temperatures, reducing measurement uncertainties and ensuring reliable operation by accounting for temperature-induced changes in viscosity and pressure.
Implementation Method 1
heating the fluid medium to a predetermined temperature with a heating device
Implementation Method 2
a weighing device (140, 142) for weighing the fluid medium
Data Source
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AI summary
A method for calibrating flow meters for fluid media comprises the steps of guiding a medium (102) through a reference measuring section (101-1) and a test measuring section (101-2) which has a flow meter to be calibrated, establishing at least approximately identical and constant pressure and flow conditions for the medium (102) in both measuring sections (101-1, 101-2), detecting a reference throughflow of the medium (102) through the reference measuring section (101-1) and throughflow values which correspond temporally thereto and are measured by the flow meter (125) to be calibrated of the test measuring section at a preset medium temperature, comparing the detected reference throughflow through the reference measuring section (101-1) with the throughflow values which correspond temporally thereto of the flow meter (125) to be calibrated, in order, based on this, to determine at least one correction value for the calibration of the flow meter (125) at the preset medium temperature, and determining of the respective correction value for the flow meter (125) for different medium temperatures of the medium (102), in order to determine a calibrating function using the temperature-dependent correction values as grid points.