Dilute Chemical Mixing With Conductivity Feedback Control
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Solution Overview
Problem
Conventional dilute chemical solution production devices are complex, costly, and face challenges in uniformly dispersing a slight amount of chemical solution in ultrapure water, requiring multiple components and precise pressure control.
Innovation Solution
A dilute chemical solution production device that measures conductivity downstream of the connection point between pipes to control the injection amount of the second liquid, ensuring a stable concentration through a simple structure with a pump and conductivity measuring means, and employs pipe configurations to promote turbulent flow for uniform dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional dilute chemical solution production device is used, then the chemical solution can be supplied to ultrapure water, but the device structure becomes complicated and costly due to requiring both a diluted chemical solution production device and a dilute chemical solution production device
Solution Approach 1:
The patent combines the diluted chemical solution production function and the dilute chemical solution production function into a single integrated device. The chemical solution reservoir stores the original chemical solution, while the ultrapure water reservoir provides the diluting liquid. A pump system with flow rate controlling means supplies these liquids to a mixing chamber where they are mixed to produce the final dilute chemical solution, eliminating the need for separate production devices.
Solution Approach 2:
The single device performs multiple functions: it stores both the chemical solution and ultrapure water, controls the flow rates of both liquids, mixes them in appropriate proportions, and supplies the final dilute chemical solution. This multi-functional design reduces device complexity while maintaining supply stability through integrated control mechanisms.
2Device complexity
If a slight amount of undiluted chemical solution is added directly to ultrapure water, then the device becomes more compact, but it becomes difficult to stably supply the chemical solution at the desired concentration
Solution Approach 1:
The patent incorporates flow rate detecting means that monitors the flow rates of both the chemical solution and ultrapure water. This feedback information is used by the flow rate controlling means to adjust the supply rates and maintain the desired mixing ratio, ensuring precise concentration control even when supplying small amounts of chemical solution.
Solution Approach 2:
The device uses a pump system with variable flow rate control that can dynamically adjust the supply rates of both chemical solution and ultrapure water. This dynamic control capability allows the system to maintain precise concentration ratios regardless of the absolute flow rates, enabling stable supply of dilute chemical solutions with varying requirements.
3Productivity
If pressure control is used to push out chemical solution little by little, then the chemical solution can be supplied at controlled rates, but the device requires precise pressure control and multiple measurements increasing complexity
Solution Approach 1:
The patent replaces the pressure control mechanism with a pump-based flow rate control system. Instead of using pressure to push the chemical solution through the system, a pump actively controls the flow rate of the chemical solution from the reservoir to the mixing chamber. This mechanical substitution simplifies the control system by directly controlling flow rate rather than relying on pressure measurements and conversions.
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 device achieves a dilute chemical solution with a desired concentration by stabilizing the injection amount based on conductivity measurements, providing uniform dispersion and reducing complexity and cost.
Implementation Method 1
a conductivity measuring means provided on a downstream side of a connection site between the first pipe and the second pipe with respect to a flow direction of the first liquid
Implementation Method 2
a pump that adds the second liquid into the first pipe through the second pipe
Data Source
AI summary
Dilute chemical solution production device (1) has a plunger pump and a chemical solution supply pipe (3) that supply a chemical solution S from a chemical solution reservoir. The end of the chemical solution supply pipe (3) serves as an injection point 11 for the chemical solution (S). The chemical solution supply pipe (3) is inserted to an approximately central position in the radial direction of an ultrapure water passage (12), which is a first pipe, via a bore-through joint (13). Conductivity meter (14) as a conductivity measuring meter is provided on the downstream side of the bore-through joint (13), which serves as the injection point (11), and is connected to a controller so that the plunger pump (4) can be controlled in accordance with the measured value of the conductivity meter (14).