Calibration Device Buoyant Force Error Correction
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Solution Overview
Problem
Calibration devices for hydrogen gas filling apparatuses face errors due to varying buoyant forces caused by temperature changes, especially when filling high-pressure hydrogen at -40°C, which affects the accuracy of weight measurements.
Innovation Solution
A calibration device with a control unit that measures the weights of the measurement housing before and after filling, calculates the variation in buoyant force based on solid capacity and gas densities, and uses a semi-enclosed structure with a dry gas pipe and dew-point instrument to manage humidity, ensuring accurate measurements by accounting for buoyant forces from gases like dried air and nitrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen gas is filled at high pressure to shorten filling time, then productivity is improved, but temperature of the gas increases which may cause breakage of fuel tanks
Solution Approach 1:
The hydrogen gas is cooled to -40°C before being filled into the fuel tank. This preliminary cooling action prevents temperature increase during high-pressure filling, allowing both high productivity and safe temperature conditions to be achieved simultaneously.
2Temperature
If hydrogen gas cooled at -40°C is filled in the calibration device, then temperature control is improved to prevent fuel tank breakage, but temperature variation of the calibration device causes buoyant force changes which generate measurement errors
Solution Approach 1:
The control unit calculates the buoyant force acting on the measurement housing and its internal components based on gas density changes, and applies a compensating correction to the weight measurement. This counteracts the measurement error caused by buoyant force variations, maintaining high measurement precision even when temperature varies during cooled hydrogen filling.
3Device complexity
If the calibration device measures weight before and after hydrogen filling to determine filling amount, then measurement simplicity is maintained, but buoyant force variation due to temperature change causes errors in the measured filling amount
Solution Approach 1:
The control unit continuously monitors temperature changes in the measurement housing and calculates the corresponding buoyant force variation. This feedback information is used to dynamically correct the weight measurement, ensuring accurate filling amount determination while maintaining the simple before-and-after weighing methodology.
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 solution effectively eliminates errors caused by buoyant force variations, improving the accuracy of hydrogen gas filling amount measurements and ensuring reliable calibration of hydrogen gas filling apparatuses.
Implementation Method 1
measuring weights of the measurement housing 1 before and after filling the fuel gas by means of a scale for measuring a weight of the measurement housing 1
Implementation Method 2
temperature of the calibration device varies, which causes buoyant force acting on the calibration device by an ambient gas to change
Data Source
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AI summary
To provide a calibration device for apparatus filling a gas such as hydrogen gas and capable of precisely measuring quantity of the gas that is filled at high pressure. A calibration device of the present invention includes: a filling vessel 2, accommodated in a measurement housing 1, to the filling vessel 2 a high pressure fuel gas such as hydrogen gas being fed from outside of the measurement housing 1; a scale 3 for measuring a weight of a fuel gas fed to the filling vessel 2; and a control device CU for eliminating an error caused by changing buoyant force from a gas in the measurement housing before and after filling the fuel gas.