Ultrapure Water Resistivity Control via Dynamic Flow Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for adjusting the specific resistance value of ultrapure water, particularly in semiconductor and liquid crystal manufacturing, face challenges in maintaining low resistance values when flow rates are small, often requiring multiple bypass pipes, which increases system scale and complexity.
Innovation Solution
A specific resistance value adjustment apparatus that distributes ultrapure water between a hollow fiber membrane module and a bypassing pipe, using a control valve to adjust the flow rate and prevent increases in resistance by dissolving adjustment gas in the ultrapure water, thereby maintaining stable resistance values without the need for multiple bypass pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple bypassing pipes are provided to maintain specific resistance value at small flow rates, then the specific resistance value stability is improved, but the device complexity and system scale increase
Solution Approach 1:
The patent applies dynamics by making the bypassing pipe flow rate adjustable based on operating conditions. A control unit dynamically adjusts the flow rate of the bypassing pipe according to the total flow rate and specific resistance value, allowing the system to adapt to varying demands without requiring multiple fixed bypassing pipes. This dynamic adjustment resolves the contradiction by maintaining reliability through active control while reducing device complexity compared to multiple static bypassing pipes
Solution Approach 2:
The patent changes the flow rate parameter of the bypassing pipe dynamically based on operating conditions. By adjusting the bypassing pipe flow rate according to the total flow rate and specific resistance value, the system maintains stable specific resistance values across different operating points without requiring multiple bypassing pipes. This parameter change approach resolves the contradiction between reliability and device complexity
2Reliability
If the flow rate of ultrapure water supplied to the hollow fiber membrane module decreases, then the specific resistance value increases, but reducing the flow rate through the module reduces productivity
Solution Approach 1:
The patent segments the ultrapure water flow into two paths: one through the hollow fiber membrane module for gas dissolution and another through the bypassing pipe. By controlling the bypassing pipe flow rate, the system ensures sufficient flow through the membrane module to maintain low specific resistance values, thereby resolving the contradiction between reliability and productivity by optimizing the flow distribution between the two segments
Solution Approach 2:
The patent implements feedback control where the control unit adjusts the bypassing pipe flow rate based on the total flow rate and specific resistance value measurements. This feedback mechanism ensures that the hollow fiber membrane module receives adequate flow to maintain low specific resistance values while the bypassing pipe compensates for flow variations, resolving the contradiction between reliability and productivity
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 apparatus effectively suppresses increases in specific resistance values even at low flow rates, reducing system scale and complexity while maintaining accurate resistance adjustments, thereby preventing dielectric breakdown and reattachment of fine particles.
Implementation Method 1
a gas such as a carbonic acid gas or an ammonia gas is dissolved in ultrapure water by using a hollow fiber membrane module
Implementation Method 2
the adjustment gas permeating the hollow fiber membrane is dissolved in the liquid
Implementation Method 3
the opening degree of the control valve opening and closing the module passing pipe is set in response to the first flow rate of the liquid
Implementation Method 4
the liquid supplied to the liquid supply pipe is distributed by the branch portion to the liquid supplied to the hollow fiber membrane module and the liquid bypassing the hollow fiber membrane module
Implementation Method 5
the adjustment gas addition liquid produced by the hollow fiber membrane module and the liquid bypassing the hollow fiber membrane module are joined to each other at the joint portion
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A specific resistance value adjustment apparatus includes: a hollow fiber membrane module 2; a module passing pipe 5 which passes through the hollow fiber membrane module 2; a bypassing pipe 6 which bypasses the hollow fiber membrane module 2; a liquid discharge pipe 7 which communicates with the module passing pipe 5 and the bypassing pipe 6 through a joint portion 14 in which the module passing pipe 5 and the bypassing pipe 6 are joined to each other at a downstream side of the hollow fiber membrane module 2; a first flow rate detection unit 8 which detects a first flow rate of a liquid L flowing to at least one of a liquid supply pipe 4 and the liquid discharge pipe 7; a control valve 9 which opens and closes the module passing pipe 5; and a control unit 10 which sets an opening degree of the control valve 9 in response to the first flow rate detected by the first flow rate detection unit 8.