Pneumatic Classifier Grooves for Stable Fine-Particle Separation
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Solution Overview
Problem
Existing pneumatic classifiers struggle to achieve a smaller classification point while maintaining classification accuracy and stability over time, particularly when dealing with fine particles used in semiconductor substrates and high-precision machining materials.
Innovation Solution
A pneumatic classifier design featuring a casing with a classifying chamber, a classifying plate, and groove portions on the ceiling wall and classifying plate, combined with cylindrical portions and air nozzles, to create a whirling stream that separates feed powder into fine and coarse particles effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the classification point is reduced to achieve smaller particle size separation, then the manufacturing precision is improved, but the classification accuracy and stability deteriorate over time
Solution Approach 1:
The patent applies local quality by providing groove portions at specific locations on the ceiling wall and classifying plate, rather than uniformly across the entire surface. These localized grooves prevent powder adhesion in critical areas where particles accumulate, thereby maintaining classification accuracy at smaller particle sizes without compromising stability over time.
Solution Approach 2:
The patent converts the harmful effect of powder adhesion to a beneficial design feature by incorporating groove portions that intentionally guide powder flow. The grooves channel particles away from adhesion-prone surfaces, transforming what would be a contamination problem into a controlled flow path that maintains classification precision.
2Reliability
If groove portions are added to prevent powder adhesion, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent segments the internal surfaces of the classifying chamber into distinct functional zones: groove portions are provided on the ceiling wall and classifying plate separately from the main flow paths. This segmentation allows targeted prevention of adhesion in specific areas without redesigning the entire apparatus, thereby improving reliability with minimal added 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 design allows for a smaller classification point with improved stability and accuracy, preventing adhesion of powder and ensuring efficient separation of fine and coarse particles over time.
Implementation Method 1
classifies feed powder having a particle size distribution into fine powder and coarse powder according to a desired particle size (classification point) using a balance between a centrifugal force imparted to the powder through a whirling stream formed from gas and a drag
Implementation Method 2
using a balance between a centrifugal force imparted to the powder through a whirling stream formed from gas and a drag
Data Source
AI summary
A pneumatic classifier includes: a casing having a ceiling wall and an annular wall; a classifying plate disposed such that a surface of the classifying plate faces the ceiling wall; a classifying chamber constituted between the ceiling wall and the surface of the classifying plate; a gas supply section configured to supply gas into the classifying chamber to generate a whirling stream; a feed powder supply section configured to supply feed powder to the whirling stream; a fine powder discharging port provided at a central part of one of the ceiling wall of the casing and the surface of the classifying plate; a coarse powder discharging port opening along an outer periphery of the classifying chamber on a side of the ceiling wall or the surface of the classifying chamber; and a groove portion provided in at least one of the ceiling wall or the surface of the classifying plate.