Multi-Chamber Gas Flow Meter for Low-Noise Transient Verification
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Solution Overview
Problem
Existing mass flow controllers (MFCs) face challenges in accurately measuring gas flow rates under various conditions due to noise and accuracy issues, particularly during transient changes and stability testing, which are not effectively addressed by single-chamber rate-of-change flow meters.
Innovation Solution
A multi-chamber rate-of-change flow meter system with N chambers, pressure sensors, and flow restrictors is employed to calculate gas flow rates by measuring the rate of pressure change across multiple chambers, improving noise reduction and accuracy through differential pressure sensing and redistribution of gas among chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single-chamber rate-of-change flow meter is used, then the device complexity is low, but the measurement precision deteriorates due to noise and accuracy issues under various flow conditions
Solution Approach 1:
The single-chamber flow meter is divided into multiple chambers (first chamber and second chamber), each equipped with its own pressure sensor. This segmentation allows differential pressure sensing across chambers, which improves measurement precision by reducing noise while distributing the measurement function across multiple simpler units rather than requiring one complex chamber
2Measurement precision
If multiple pressure sensors with different ranges are used, then the measurement precision improves for detecting small and fast flow deviations, but the device complexity increases
Solution Approach 1:
Different pressure sensors are assigned to different chambers based on their specific measurement needs. Each pressure sensor can be optimized for its local measurement range, allowing the system to detect both small and large flow deviations with appropriate precision. This local optimization improves overall measurement capability while keeping each sensor's function relatively simple
3Measurement precision
If gas redistribution among chambers is implemented, then the measurement precision improves through differential pressure sensing, but the device complexity increases due to additional flow restrictors and control mechanisms
Solution Approach 1:
The gas redistribution function is extracted and implemented through simple flow restrictors placed between chambers, rather than requiring complex active control mechanisms. This passive redistribution approach enables differential pressure sensing and improves measurement precision while minimizing the addition of complex control systems
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 multi-chamber system enhances the detection of small and fast flow deviations, reduces noise in calculated flow signals, and maintains accuracy by using multiple pressure sensors with different ranges and flow restrictors, enabling more reliable assessment of MFCs during development and troubleshooting.
Implementation Method 1
N pressure sensors coupled to corresponding chambers, and means for redistributing the gas among the chambers. A measurement module is coupled to the pressure sensors to obtain a rate of change of pressure in each of the chambers
Data Source
AI summary
A multi-chamber rate-of-change flow meter system and methods for operating the same are disclosed. The multi-chamber rate-of-change flow meter system includes a collection of N chambers, means for drawing a gas into or out of the collection of N chambers, N pressure sensors corresponding one of the N chambers, and means for redistributing the gas among the chambers. A measurement module is coupled to the pressure sensors to obtain a rate of change of pressure in each of the chambers due to the redistribution of the gas and calculate a flow rate of the gas flowing into or out of the collection of N chambers based upon the rate of change of pressure in each of the chambers.