Nebulizer Flow Sensor for Ultra Pure Water Residue Monitoring
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Solution Overview
Problem
Existing systems for measuring non-volatile residue in ultra pure water face challenges such as inaccurate flow rate measurement, waste water accumulation, gas bubble formation, and slow response times, which can lead to defects in semiconductor devices due to contamination.
Innovation Solution
A nebulizer system that uses a microbore tubing to control flow rate and minimize gas bubble formation, combined with a flow sensor to measure waste water output flow rate digitally, and a condensation particle counter using water as the condensing medium for real-time residue concentration detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotometer is used to measure flow rate, then flow rate measurement is possible, but the system becomes expensive and complex due to the need for ultra-clean materials
Solution Approach 1:
The patent extracts the flow measurement function from the traditional rotometer design and relocates it to a digital flow sensor positioned downstream in the waste water path. This separation allows the use of standard, less expensive materials in the measurement path while maintaining measurement capability through a different technological approach (digital sensing rather than mechanical rotation measurement).
Solution Approach 2:
The patent replaces the mechanical rotometer system with a digital flow sensor that uses electronic sensing rather than mechanical measurement. This substitution eliminates the need for ultra-clean mechanical components and reduces overall system complexity while providing equally accurate flow rate measurement through digital signal processing.
2Reliability
If butyl alcohol is used for growing droplets, then droplet growth is effective, but health and environmental hazards arise
Solution Approach 1:
The patent changes the chemical parameter of the condensing medium from butyl alcohol to water. This parameter change maintains the droplet growth function (water vapor condensing onto residue particles) while eliminating the health and environmental hazards associated with butyl alcohol. The system achieves the same scientific effect through a different substance with safer properties.
Solution Approach 2:
The patent uses water as a safe, inexpensive, and environmentally benign condensing medium that can be easily disposed of or reused, replacing the hazardous butyl alcohol. Water serves the same functional purpose without the toxicological concerns, making the system more sustainable and safer for indoor environments.
3Ease of operation
If a sapphire orifice plate is used to control flow rate, then flow rate is controlled, but gas bubbles form and disrupt measurements
Solution Approach 1:
The patent removes the sapphire orifice plate from the water delivery path and replaces it with a flow control valve. This extraction eliminates the source of gas bubble formation (the orifice plate) while maintaining flow rate control capability through the valve's adjustable opening mechanism.
Solution Approach 2:
The patent converts the potential harm of gas bubbles into a benefit by using a flow control valve that can be adjusted to operate at lower pressures, preventing bubble formation in the first place. The valve provides the same flow control function without creating the harmful side effect of dissolved gas accumulation.
4Productivity
If waste water accumulates in the nebulizer, then the nebulizer continues to operate, but measurement accuracy decreases over time
Solution Approach 1:
The patent implements a feedback mechanism through the digital flow sensor that continuously monitors waste water flow rate and provides real-time data on system performance. This feedback allows the system to detect changes in flow characteristics that indicate waste water accumulation and trigger alerts or adjustments to maintain measurement accuracy throughout operation.
Solution Approach 2:
The patent maintains continuous operation by using the flow sensor to monitor waste water removal in real-time, ensuring that the nebulizer operates within optimal parameters throughout extended periods. The continuous monitoring enables timely intervention to prevent accumulation effects from degrading measurement quality.
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 system provides accurate and real-time measurement of non-volatile residue concentrations, reducing the risk of contamination and enabling immediate corrective action, while avoiding the health and environmental hazards associated with previous chemicals used.
Implementation Method 1
a nebulizer to convert the liquid test sample into an aerosol of droplets
Implementation Method 2
heating element to evaporate the test sample from the aerosol droplets, thereby leaving non-volatile residue particles
Implementation Method 3
condensing medium that condenses onto the non-volatile residue particles to form larger droplets
Data Source
AI summary
A system for monitoring non-volatile residue concentrations in ultra pure water includes a nebulizer for generating an aerosol composed of multiple water droplets, a heating element changing the aerosol to a suspension of residue particles, and a condensation particle counter to supersaturate the dried aerosol to cause droplet growth through condensation of a liquid onto the particles. The nebulizer incorporates a flow dividing structure that divides exiting waste water into a series of droplets. The droplets are counted to directly indicate a waste water flow rate and indirectly indicate an input flow rate of water supplied to the nebulizer. The condensation particle counter employs water as the condensing medium, avoiding the need for undesirable chemical formulations and enabling use of the ultra pure water itself as the condensing medium.