Mass Flow Controller Estimation for Non-Critical Flow Measurement
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Solution Overview
Problem
Current pressure-based mass flow controllers (MFCs) require two pressure sensors to measure non-critical flow, increasing manufacturing costs due to the need for both an upstream and a downstream pressure sensor.
Innovation Solution
A system that uses a single upstream pressure sensor to estimate the downstream pressure and compute the flow rate, allowing for accurate flow measurement in non-critical flow conditions without the need for a separate downstream pressure sensor, using equations and iterative calculations to converge on accurate values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two pressure sensors are used to measure non-critical flow, then flow measurement accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the downstream pressure measurement function from a separate physical sensor and implements it through computational estimation using the upstream pressure sensor data and flow equations. This removes the need for the second pressure sensor while maintaining measurement capability through mathematical modeling of the flow system.
Solution Approach 2:
The patent creates a virtual copy of the downstream pressure measurement through computational estimation rather than using a physical sensor. The estimated downstream pressure is calculated by solving flow equations that replicate what a physical sensor would measure, enabling accurate flow measurement without the additional hardware cost.
2Ease of manufacture
If a single upstream pressure sensor is used, then manufacturing cost is reduced, but the ability to measure non-critical flow accurately deteriorates
Solution Approach 1:
The patent introduces computational estimation algorithms as an intermediary between the single upstream pressure sensor and the flow measurement output. These algorithms use the upstream pressure data along with system parameters and flow equations to mediate and derive accurate non-critical flow measurements without requiring direct downstream pressure sensing.
Solution Approach 2:
The patent changes the measurement approach from direct physical measurement of downstream pressure to computational derivation based on upstream pressure parameters. By transforming the measurement problem into a parameter estimation problem using flow equations, the system achieves accurate non-critical flow measurement with reduced hardware parameters.
Data Source
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AI summary
Methods, systems, and apparatus for pressure-based flow measurement are provided. A processor receives, from the pressure-based mass flow controller (MFC), an upstream pressure value P u . The processor computes, for the pressure-based mass flow controller (MFC), a downstream pressure value P d based on the received upstream pressure value P u . The processor computes, for the pressure-based mass flow controller (MFC), a flow rate Q based on the received upstream pressure value P u and the computed downstream pressure value P d .The processor controls a flow through the pressure-based mass flow controller (MFC) based on the computed flow rate Q. The methods, systems, and apparatus can be used for flow measurement in non-critical or un-choked flow conditions.