Mass Flowmeter-Based NO/N2 Gas Mixture Control
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Solution Overview
Problem
The existing methods for packaging NO/N2 gas mixtures in gas cylinders suffer from low mixing precision due to factors like the Bourdon effect, limited accuracy of NO pressure sensors, and temperature influences, leading to significant errors in the NO content.
Innovation Solution
An installation using mass flowmeters to control the flow of NO and N2 gases, eliminating the need for weighing and pressure sensor measurements, and incorporating a control device to set and maintain precise mass flow setpoints, thereby reducing errors and ensuring accurate mixture composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors and weighing methods are used to control gas filling, then the packaging process can be implemented, but the measurement precision and mixing precision are low due to Bourdon effect, sensor limitations, and temperature influences
Solution Approach 1:
The patent replaces mechanical weighing systems and pressure-based measurement systems with mass flowmeters that directly measure the mass flow rate of gases. This substitution eliminates the Bourdon effect (mechanical hose deformation during weighing) and temperature-dependent pressure measurements, providing direct and accurate mass flow measurement independent of these harmful factors.
Solution Approach 2:
The patent changes the measurement parameter from pressure (which is temperature-dependent) and weight (which suffers from Bourdon effect) to mass flow rate. By measuring the actual mass of gas flowing through the system per unit time, the system achieves temperature-independent and mechanically stable measurements, directly addressing the precision limitations of previous methods.
2Productivity
If pressure-based NO quantity determination is used, then the packaging process can proceed, but temperature variations cause significant errors in NO content calculation
Solution Approach 1:
The patent replaces the thermodynamic calculation method (PV = ZnRT requiring temperature measurement and calculation) with direct mass flow measurement. The mass flowmeters provide direct readout of gas mass flow rate without requiring temperature compensation calculations, eliminating the source of temperature-related errors while maintaining packaging productivity.
Solution Approach 2:
The patent introduces mass flowmeters as intermediary measurement devices between the gas sources and filling system. These flowmeters act as mediators that directly quantify the mass of NO and N2 being transferred, providing an intermediate measurement that is independent of temperature and pressure variations, thereby ensuring precise mixture composition throughout the packaging process.
3Ease of manufacture
If separate NO and N2 filling processes are used, then the packaging can be completed, but the mixing precision is low due to cumulative errors from multiple measurement steps
Solution Approach 1:
The patent implements continuous mass flow measurement of both NO and N2 gases throughout the filling process. By continuously monitoring and controlling the mass flow rates of both gases simultaneously, the system maintains precise control over the mixture composition throughout the entire packaging operation, eliminating cumulative errors that would arise from discrete, separate measurement steps.
Solution Approach 2:
The patent employs feedback control through the mass flowmeters and control system. The flowmeters continuously provide feedback on the actual mass flow rates of NO and N2, allowing the control system to adjust filling parameters in real-time to maintain the desired mixture composition. This closed-loop feedback ensures high precision in the final mixture despite variations in operating conditions.
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 use of mass flowmeters significantly reduces NO content errors from 7% to less than 1%, enhancing the precision and reliability of the NO/N2 gas mixture packaging process.
Implementation Method 1
each comprising a mass flowmeter, each mass flowmeter being connected to a control device cooperating with each mass flowmeter
Data Source
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AI summary
The invention relates to a conditioning system for a NO/N2 gas mixture in at least one container comprising a gaseous NO source (1), a gaseous nitrogen source (2), at least one filling manifold (3) comprising one or more filling stations (24) for gas containers (25), a first gas line (11) fluidly connecting the gaseous NO source (1) to the filling manifold (3), and a second gas line (12) fluidly connecting the gaseous nitrogen source (1) to the filling manifold (3). The first gas line (11) and the second gas line (12) each comprise a mass flow meter (4, 5), each mass flow meter (4, 5) being connected (14, 15) to a control device (6) cooperating with each mass flow meter (4, 5).