Diamond-Coated Nozzle Cleaning Device for Polysilicon Reactors
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Solution Overview
Problem
Conventional methods for cleaning the inner wall surface of reactors used in polycrystalline silicon production are inadequate in removing firmly attached substances, leading to incomplete removal and potential hydrogen chloride formation, and existing techniques either lack sufficient physical removal ability or cause nozzle erosion.
Innovation Solution
A cleaning device with nozzles that discharge a cleaning liquid containing abrasive particles at a controlled pressure and distance to ensure effective dirt removal without excessive nozzle erosion, featuring a dual-nozzle system for comprehensive surface coverage and a driving mechanism for precise movement along the reactor's curved and cylindrical surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high-speed jet of inert gas or high-pressure jet of pure water is used to remove attached substance, then the physical removal ability is improved, but the nozzle erosion increases and cleaning ability is reduced over time
Solution Approach 1:
The patent changes the material parameter of the nozzle from conventional materials to diamond coating or diamond material, which has significantly higher hardness and erosion resistance. This allows the nozzle to maintain its cleaning ability and structural integrity even when exposed to high-pressure abrasive cleaning liquids, thereby resolving the contradiction between physical removal ability and nozzle durability
Solution Approach 2:
The patent employs composite material structure by coating the nozzle surface with diamond or using diamond composite materials. This combines the structural integrity of the base material with the extreme hardness and erosion resistance of diamond, enabling the nozzle to withstand high-pressure abrasive flows while maintaining effective cleaning performance
2Reliability
If carbon dioxide pellets or ice particles are used to remove attached substance, then the nozzle erosion is reduced, but the hydrolysis of attached substance does not proceed and cleaning ability is insufficient
Solution Approach 1:
The patent merges two cleaning mechanisms into one system: (1) physical impact removal using abrasive particles in high-pressure liquid, and (2) chemical hydrolysis of attached substance. The abrasive cleaning liquid simultaneously provides mechanical cleaning force and promotes hydrolysis reaction, achieving both nozzle durability and effective cleaning ability
Solution Approach 2:
The patent introduces water or steam as an intermediary substance that facilitates hydrolysis of the attached silicon-based material. The cleaning liquid serves as a mediator that both mechanically impacts the deposits and chemically promotes their breakdown through hydrolysis, enhancing overall cleaning effectiveness
3Area of stationary object
If a rotating brush is used to clean the inner wall, then the cleaning coverage is improved, but it is difficult to cover uneven inner wall surface thoroughly and cleaning completeness is reduced
Solution Approach 1:
The patent replaces mechanical brush contact with high-pressure liquid jet technology. The cleaning liquid is delivered through hoses to nozzles that can be precisely positioned against the inner wall surface, allowing the flexible liquid stream to conform to uneven surfaces and achieve complete coverage without the limitations of rigid brush structures
Solution Approach 2:
The patent employs a movable nozzle system that can dynamically adjust its position and orientation to follow the contours of the bell jar's inner wall. The nozzle assembly can move vertically and rotate to maintain optimal cleaning angles across the entire inner surface, ensuring thorough cleaning coverage that adapts to surface geometry
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 solution achieves reliable removal of substances from the reactor's inner surface, maintaining a reflectance of at least 0.7 and preventing nozzle damage, while ensuring efficient cleaning without sacrificing cleaning ability or causing erosion.
Implementation Method 1
a cleaning liquid containing abrasive particles is discharged at a state in which an impingement pressure, at which the cleaning liquid impinges on the inner wall surface, ensures a pressure for removing dirt on the inner wall surface
Implementation Method 2
causing a cleaning liquid containing abrasive particles to be discharged at a state in which an impingement pressure, at which the cleaning liquid impinges on the inner wall surface, ensures a pressure for removing dirt on the inner wall surface
Implementation Method 3
erosion of nozzles for discharging the cleaning liquid occurs by not more than 500 μm/hour
Implementation Method 4
erosion of nozzles for discharging the cleaning liquid occurs by not more than 500 μm/hour
Data Source
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AI summary
A method of cleaning an inner wall surface (502) of a bell jar (500), by causing nozzles (112, 122) to discharge a cleaning liquid which contains abrasive particles, includes the steps of: (a) causing the nozzles (112, 122) to discharge the cleaning liquid at a discharge pressure at which erosion of the nozzles (112, 122), due to the cleaning liquid, occurs by not more than 500 µm / hour; and (b) adjusting a distance between the inner wall surface (502) and the nozzles (112, 122) so that an impingement pressure, at which the cleaning liquid impinges on the inner wall surface (502), secures a pressure at which dirt on the inner wall surface (502) can be removed.