Microwave Plasma Spheroidisation Flow Divider for Wall Fouling Control
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Solution Overview
Problem
Existing powder spheroidisation processes using microwave-induced plasma suffer from powder adherence to the inner wall of the plasma chamber, leading to issues such as shielding, damage, and impaired cooling.
Innovation Solution
The apparatus and method employ a flow divider within the confinement tube to separate the incoming gas flow into a central and peripheral flow, where the central flow produces the plasma torch and the peripheral flow cools and cleans the inner wall of the plasma chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single gas flow is used to produce plasma in the chamber, then plasma generation is achieved, but powder adheres to the chamber wall causing shielding and damage
Solution Approach 1:
The gas flow is segmented into two separate flows: a central gas flow that produces the plasma torch and a peripheral gas flow that cools and cleans the chamber wall. This segmentation allows each flow to perform its specific function without interfering with the other, preventing powder adherence while maintaining plasma generation stability
Solution Approach 2:
Different regions of the gas flow are given different qualities and functions: the central region generates plasma while the peripheral region provides cooling and cleaning. This local differentiation ensures that the chamber wall is protected from powder adherence while the plasma generation area maintains optimal conditions
2Temperature
If the chamber wall is cooled from outside, then cooling is achieved, but powder can still adhere and form protective coatings
Solution Approach 1:
A peripheral gas flow acts as an intermediary between the plasma generation region and the chamber wall. This intermediate flow cools the chamber wall and simultaneously prevents powder from adhering to it, eliminating the need for external cooling systems while protecting the wall from powder coating
Solution Approach 2:
The system uses its own gas flow to provide both plasma generation and wall cooling/cleaning functions. The peripheral gas flow self-performs the cooling and cleaning tasks that would otherwise require separate external systems, preventing powder adherence while maintaining wall temperature control
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
This approach effectively prevents powder adherence to the chamber wall, maintaining plasma stability and efficient cooling, thereby ensuring consistent spheroid production.
Implementation Method 1
a generator of microwave radiation for a microwave cavity
Implementation Method 2
a microwave-induced plasma is a type of plasma that has high frequency electromagnetic radiation in the GHz range. It is capable of exciting electrodeless gas discharges
Implementation Method 3
carrying the powder precursor into the plasma torch by means of the process gas acting as a carrier gas
Implementation Method 4
The powder precursor of irregular (angular or non-uniform) shape (often from waste materials) is carried into an induction or microwave-induced plasma and is melted immediately in the high temperatures of plasma
Implementation Method 5
microwave-induced plasma
Implementation Method 6
the peripheral flow can be driven to cool and clean the inner wall thereof
Implementation Method 7
The melted powder particles assume a spherical shape under the action of the surface tension of the liquid state
Data Source
Figure 1~2
Figure 3~6
Figure 5~7
AI summary
An apparatus for powder spheroidisation comprises a microwave cavity (20), a plasma chamber (35) that has an inner wall and is located in the microwave cavity, a confinement tube (3) connected to the plasma chamber, a receptacle for a mixture of a process gas and a powder precursor, the receptacle being connected to the confinement tube to feed said mixture as an incoming gas flow to the plasma chamber, in order to produce a plasma torch therein by coupling the gas flow with microwave radiation, and a flow divider (110) that is located within the confinement tube at the entrance of the plasma chamber, the flow divider providing a broad passageway (118) and a narrow passageway (113), and causing the incoming gas flow to separate into a central gas flow through the broad passageway, and a peripheral gas flow through the narrow passageway.