Differential-Pressure Flow Meter Dead Volume Elimination
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Solution Overview
Problem
Differential-pressure-based flow meters used in semiconductor and allied industries face issues with 'dead volumes' that can trap contaminants, potentially leading to defects in integrated circuits during fabrication.
Innovation Solution
The development of differential-pressure-based flow meters that eliminate 'dead volumes' by direct hydraulic or pneumatic communication between the fluid flow path and the flow sensor, ensuring continuous flushing and preventing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dead volumes are present in the flow meter design, then the device complexity is reduced and manufacturing is easier, but contaminants can be trapped leading to reduced reliability and measurement precision
Solution Approach 1:
The patent removes dead volumes from the flow meter design by implementing a streamlined flow path that eliminates stagnant regions where contaminants could be trapped. The flow path is designed to ensure continuous fluid movement through all components, extracting the problematic dead volume elements from the system geometry.
Solution Approach 2:
The design incorporates preliminary flushing action by ensuring the flow path geometry naturally promotes continuous fluid movement that prevents contaminant accumulation before it can affect measurements. The streamlined design proactively prevents contamination rather than relying on post-contamination cleaning.
2Measurement precision
If dead volumes are eliminated through direct hydraulic communication, then measurement precision and reliability improve, but the device complexity increases
Solution Approach 1:
The patent merges the flow path and sensor housing into an integrated structure where the flow path is formed directly within the sensor assembly. This consolidation eliminates separate dead volume regions and ensures continuous flushing while avoiding the complexity of additional separate components and connections.
Solution Approach 2:
The design employs a diaphragm or membrane structure that allows direct pressure transmission from the flow path to the sensor while maintaining a compact, integrated geometry. This thin-film approach enables direct hydraulic communication without requiring complex rigid piping or additional chambers that would create dead volumes.
3Reliability
If continuous flushing is implemented, then contamination is prevented improving reliability, but energy consumption increases
Solution Approach 1:
The flow meter design uses the process fluid itself to provide continuous flushing through its normal operational flow. The geometry is designed so that the working fluid automatically flushes through the flow path and sensor regions during regular operation, eliminating the need for separate flushing systems or additional energy-consuming pumping actions.
Solution Approach 2:
The streamlined flow path design ensures that the useful action of fluid flow continues uninterrupted through all components including sensor regions. The geometry maintains continuous fluid movement during normal operation, preventing contaminant accumulation without requiring additional flushing cycles or energy input beyond the normal process flow.
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 design enhances the accuracy and reliability of flow measurements by preventing contamination and ensuring continuous flushing, thereby reducing the risk of defects in semiconductor processes.
Implementation Method 1
the differential-pressure sensor 101 can be considered as a type of flexible diaphragm. When the pressure on the first side 101A of the differential-pressure sensor 101 is greater than the pressure on the second side 101B of the differential-pressure sensor 101, the differential-pressure sensor 101 flexes or bends. The flexing produces an electrical signal that is proportional to the difference in the two pressures.
Data Source
AI summary
Various embodiments include apparatuses and methods to form the apparatus. In one embodiment, the apparatus is a flow meter having inlet and outlet portions for transporting a fluid along a flow path. A flow-restrictor element is formed within the flow path to impart a pressure drop to the fluid. A flow sensor has a first surface of the flow sensor in direct fluid communication with fluid flowing upstream of the flow-restrictor element and a second surface, on a portion of the flow sensor opposite to the first surface, in direct fluid communication with fluid flowing downstream of the flow-restrictor element. The flow sensor senses a differential pressure in the fluid due to the at least one flow-restrictor element. Other apparatuses and systems are disclosed.