Micro-position gap sensor for mass flow control
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Solution Overview
Problem
Existing devices face challenges in measuring small displacements at sub-millimeter or sub-micrometer scales with high precision and signal-to-noise ratio, especially in harsh environments, and mass flow control systems are slow to respond to sudden changes in fluid flow rates due to the need for incremental adjustments.
Innovation Solution
A micro-position gap sensor assembly with a structural housing, flexible diaphragm, and a parallel plate gap sensor configuration that includes a non-contact sensor plate and a target plate, where the sensor assembly is coupled to a flow control valve, allowing for direct measurement of valve position and enabling nearly instantaneous changes in flow rate by calculating the required valve position based on current pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass flow control systems use incremental adjustments to minimize overshooting and undershooting, then measurement precision is improved, but response speed deteriorates
Solution Approach 1:
The patent replaces the mechanical feedback control system with an electronic calculation-based system. The micro-position gap sensor directly measures valve position, and the controller calculates required flow rate changes electronically, eliminating the need for slow incremental mechanical adjustments while maintaining precision through direct measurement and computational control.
Solution Approach 2:
The patent uses a non-contact sensor plate that creates an electrical field copy or representation of the valve position without physical contact. This allows precise measurement of valve position and flow rate without mechanical interference, enabling rapid electronic response while maintaining measurement accuracy.
2Measurement precision
If sensor systems are miniaturized to measure sub-millimeter displacements, then measurement precision for small displacements is improved, but reliability in harsh environments deteriorates
Solution Approach 1:
The patent employs a flexible diaphragm as a protective barrier that isolates the miniaturized sensor components from harsh fluid environments. The diaphragm transmits mechanical displacement information to the sensor while preventing direct exposure to corrosive fluids, thus maintaining both measurement precision and reliability.
Solution Approach 2:
The patent replaces contact-based mechanical sensors with a non-contact electrical field-based sensing system. The micro-position gap sensor uses electrical fields to measure valve position and fluid parameters without physical contact, eliminating wear and corrosion issues while maintaining high precision for sub-millimeter displacements.
3Reliability
If non-contact sensing is used to measure valve position, then reliability by preventing fluid exposure to sensors is improved, but device complexity increases
Solution Approach 1:
The non-contact sensor plate serves multiple functions simultaneously: it measures valve position, detects fluid parameters, and provides electrical isolation from harsh environments. This multi-functionality reduces the need for separate protective components, thereby maintaining reliability while minimizing additional complexity.
Solution Approach 2:
The patent combines the sensing function and protective barrier function into a single integrated non-contact sensor assembly. The sensor plate and diaphragm work together as a unified system, eliminating the need for separate mechanical contact sensors and protective housings, thus achieving reliability without proportionally increasing complexity.
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 micro-position gap sensor assembly provides accurate and thermally stable position indication of the flow control valve, enabling rapid and precise control of fluid flow rates without relying on feedback control methods, thus overcoming the slowness of mass flow control systems.
Implementation Method 1
a parallel plate gap sensor configured such that displacement of one of the target plate or the non-contact sensor plate caused by movement of the shaft, changes a distance between the target plate and the non-contact sensor plate
Data Source
AI summary
A micro-position gap sensor assembly, including a structural housing, a flexible diaphragm fixedly attached at a first end of the structural housing, and a shaft orthogonally attached to the flexible diaphragm. The micro-position gap sensor assembly may further include a first retainer coupled to the shaft, a second retainer formed as a step of the structural housing, and a plate gap sensor. The plate gap sensor may include a non-contact sensor plate biased by a compression spring so that the non-contact sensor plate is held against a portion of the second retainer. The plate gap sensor may further include a target plate positioned adjacent the non-contact sensor plate and separated therefrom by a gap. The target plate may be biased by a return spring so that the target plate is held against a portion of the first retainer. The target plate may be coupled to the shaft.