Coriolis Flow Meter Young's Modulus Correction for Cryogenic Accuracy
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Solution Overview
Problem
Existing Coriolis flow meters face challenges in providing precise mass flow measurements at sub-zero and cryogenic temperatures due to the difficulty in characterizing flow tube stiffness changes based on Young's modulus, especially for larger flow meters, and the limitations of cryogenic calibration facilities.
Innovation Solution
A method and system for correcting mass flow measurements using a Coriolis flow meter that involves determining Young's modulus temperature corrections for density and mass flow based on known fluid density, temperature, and time period, which are then used to correct the mass flow value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature corrections are applied to mass flow measurements, then measurement accuracy is improved, but measurement precision deteriorates due to difficulty in characterizing flow tube stiffness changes at sub-zero temperatures
Solution Approach 1:
The patent applies parameter changes by using empirical data to characterize the relationship between temperature and flow tube stiffness (Young's modulus). Instead of relying on theoretical models that are difficult to validate at sub-zero temperatures, the patent uses measured empirical relationships between temperature, stiffness, and mass flow measurements to create correction factors that accurately compensate for temperature effects across a wide temperature range including sub-zero and cryogenic conditions.
Solution Approach 2:
The patent replaces complex mechanical characterization of flow tube stiffness at cryogenic temperatures with an empirical mathematical model. Rather than attempting to directly measure or mechanically characterize the stiffness changes at sub-zero temperatures through complex calibration facilities, the patent substitutes this with a computational approach that uses empirical data to calculate correction factors, thereby avoiding the need for difficult cryogenic calibration procedures.
2Measurement precision
If cryogenic calibration facilities are used to characterize flow tube stiffness, then measurement accuracy is improved, but device complexity increases due to the difficulty and cost of cryogenic calibration
Solution Approach 1:
The patent creates a computational copy or model of the temperature-stiffness-mass flow relationship based on empirical data collected at accessible temperatures. Instead of requiring physical calibration at cryogenic temperatures, the patent develops a mathematical model that replicates the effect of cryogenic temperature changes on flow tube stiffness. This virtual model can then be used to correct measurements without requiring actual cryogenic calibration facilities.
Solution Approach 2:
The patent introduces an intermediary empirical mathematical model that mediates between the complex physical reality of cryogenic flow tube stiffness and the simpler measurement process. The empirical model acts as a translator that converts temperature measurements into appropriate correction factors, eliminating the need for direct cryogenic calibration while maintaining measurement accuracy.
3Measurement precision
If empirical data is used to characterize temperature effects, then measurement accuracy is improved, but measurement precision deteriorates due to limitations in available empirical data for larger flow meters
Solution Approach 1:
The patent develops a universal empirical model that can be applied across different flow meter sizes and configurations. By collecting and analyzing empirical data from various sources, the patent creates a generalized relationship between temperature, flow tube stiffness, and mass flow measurements that works for both small and large flow meters. This universal approach eliminates the need for separate calibration data for each meter size, thereby preventing loss of information about temperature effects in larger flow meters.
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
The method and system provide accurate mass flow measurements with errors less than 0.10%, even for larger flow meters, without the need for cryogenic calibration, by accounting for temperature effects on flow tube stiffness.
Implementation Method 1
Coriolis mass flowmeters utilize Coriolis forces induced by fluid flowing through one or more vibrating tubes to measure mass flow rate
Implementation Method 2
Both flow tubes 130 and 130' are driven by driver 180 in opposite directions in a first out-of-phase bending mode of the flowmeter
Implementation Method 3
changes in temperature and fluid pressure can change the stiffness of flow tubes 130, 130', which can introduce errors in the meter mass flow and density measurements
Data Source
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AI summary
A method (300), system (400), and electronics (20) for correcting a mass flow value ṁ measured using a Coriolis flow meter (100) for temperature effects at a known fluid temperature temp below 0 C are provided. The method comprises receiving a known fluid density ρ indic , receiving the fluid temperature temp, receiving a time period Tp, determining a Young' s modulus temperature correction for density TFy D based on the known fluid density ρ indic , the known fluid temperature temp, and the time period Tp, determining a Young' s modulus temperature correction for mass flow TFy M based on a temperature correction constant k and Young' s modulus temperature correction for density TFy D , and correcting the mass flow value ṁ using the Young' s modulus temperature correction for mass flow TFy M .