Gas-Tight Sieve for Polysilicon Dedusting
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Solution Overview
Problem
Polysilicon granules are contaminated by dust particles during the dedusting process due to environmental contaminants being sucked into the screening system, leading to attachment problems and contamination issues during further processing.
Innovation Solution
A gas-tight screening system operating under excess pressure relative to the environment, where a uniform gas stream is blown in through filtration mats to transport dust particles cocurrently with the polysilicon granules, ensuring they are separated and removed as a separate fraction at the bottom of the system, preventing external contaminants from entering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a suction system is used to remove dust particles from the screening system, then dust particles are removed, but environmental contaminants are sucked into the screening system and contaminate the polysilicon granules
Solution Approach 1:
Instead of using suction to remove dust particles, the invention uses a gas stream blown in the direction of the particle flow (cocurrent flow) to transport dust particles out of the screening system. This reverses the conventional suction approach and prevents environmental contaminants from being drawn into the system while still achieving effective dust removal.
Solution Approach 2:
A gas stream serves as an intermediary medium to transport dust particles from the screening system. The gas flow carries dust particles out through the discharge opening without requiring suction, thereby avoiding the introduction of external contaminants while maintaining effective dust removal.
2Object-generated harmful factors
If the screening system is opened to allow dust removal, then dust particles can be removed, but external contaminants can enter and attach to the polysilicon granule surface
Solution Approach 1:
The screening system is operated as a closed system with a controlled gas atmosphere. The gas stream creates a protective environment that prevents external contaminants from entering the system while allowing dust particles to be transported out, thereby maintaining surface purity of the polysilicon granules throughout the dedusting process.
3Reliability
If a closed screening system is used to prevent contamination, then surface purity is maintained, but dust particles trapped inside cannot be effectively removed
Solution Approach 1:
The invention uses a pneumatic system with a gas stream to transport dust particles out of the closed screening system. The gas flow enters through the discharge opening and carries dust particles in the direction of the particle flow, enabling effective dust removal while maintaining the closed system structure and surface purity.
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
Effectively prevents surface contamination by ensuring all dust particles are removed without introducing external contaminants, improving the purity of polysilicon granules and reducing re-contamination risks.
Implementation Method 1
a uniform gas stream is blown in through filtration mats to transport dust particles cocurrently with the polysilicon granules
Implementation Method 2
a uniform gas stream is blown in through filtration mats to transport dust particles cocurrently with the polysilicon granules
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a method for classifying and dedusting polysilicon granular material, wherein the polysilicon granular material is fed into a sieve system (1), is divided into two or more fractions by means of one or more sieve surfaces (5), wherein adherent dust particles are removed from the polysilicon granular material by means of a projectile motion of the polysilicon granular material in the sieve system (1), wherein the removed dust particles are led out of the sieve system (1) by means of a gas flow fed to the sieve system (1), wherein the sieve system is gas-tight and the feeding (6) and removal (7) of the gas flow occur in such a way that there is overpressure in the sieve system (1) in relation to the surroundings, and a device suitable for performing the method.