Symmetrical Multi-Port Powder Injection Ring for Plasma Spray
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Solution Overview
Problem
Conventional plasma spray guns experience inefficiency due to powder buildup on hardware surfaces, resulting from turbulent flow conditions caused by external powder injectors disrupting the eddy current at the outlet nozzle, leading to reduced coating quality and increased downtime for cleaning.
Innovation Solution
A symmetrical multi-port powder injection ring with a shroud that encloses the eddy current and minimizes flow field disruptions, allowing powder to be injected downstream of the nozzle, reducing turbulence and powder buildup by maintaining a smooth, continuous inner wall and strategically placing ports to accommodate powder injectors without disrupting the eddy current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external powder injectors are used to increase powder feed rate, then productivity is improved, but powder buildup on hardware surfaces increases due to turbulent flow disrupting the eddy current
Solution Approach 1:
The shroud acts as an intermediary component between the plasma plume and the powder injectors. It encloses the eddy current structure and provides a controlled interface for powder injection, preventing direct disruption of the eddy current while still allowing efficient powder delivery into the plasma stream.
Solution Approach 2:
The powder injection system is segmented into multiple ports distributed around the shroud circumference. This segmentation allows powder to be injected at multiple locations downstream of the nozzle, distributing the injection points to minimize local disruption to the eddy current while maintaining overall process efficiency.
2Productivity
If more powder is injected by increasing powder feed rate at each port, then productivity is improved, but coating quality deteriorates due to process inefficiency and hardware buildup
Solution Approach 1:
The shroud serves as a mediator that decouples the powder injection process from the plasma plume dynamics. By providing a structured interface with multiple ports, it enables high powder feed rates to be maintained without the turbulence and buildup that previously degraded coating quality.
3Productivity
If internal powder injection is used to avoid external turbulence, then powder delivery efficiency is improved, but powder buildup occurs internal to the gun bore and injectors
Solution Approach 1:
The problematic eddy current structure is extracted and enclosed within the shroud, separating it from the external environment. This allows external powder injection to proceed without disrupting the enclosed eddy current, while the shroud itself protects the internal gun bore from powder buildup issues.
4Reliability
If the shroud encloses the eddy current with a smooth continuous inner wall, then flow field disruption is minimized, but device complexity increases
Solution Approach 1:
The shroud is implemented as a relatively simple annular or ring-shaped component with a smooth inner wall surface. This simple geometric form encloses the eddy current effectively while minimizing structural complexity, making the shroud a practical addition rather than a complex assembly.
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 configuration enhances powder delivery efficiency, reducing powder buildup and increasing overall process efficiency, enabling higher powder feed rates while maintaining coating quality and deposit efficiency.
Implementation Method 1
Feedstock material, typically in powder form, is injected into a high temperature plasma flame, also known as a plasma plume, where it is rapidly heated and accelerated
Implementation Method 2
Feedstock material, typically in powder form, is injected into a high temperature plasma flame, also known as a plasma plume, where it is rapidly heated and accelerated
Implementation Method 3
turbulent flow conditions caused by external powder injectors disrupting the eddy current at the outlet nozzle
Implementation Method 4
turbulent flow conditions caused by external powder injectors disrupting the eddy current
Implementation Method 5
A symmetrical multi-port powder injection ring with a shroud that encloses the eddy current and minimizes flow field disruptions
Implementation Method 6
The plasma gun is commonly used as a process tool in the spray coatings industry
Implementation Method 7
a high temperature plasma flame, also known as a plasma plume
Data Source
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AI summary
Powder injection apparatus (50), a plasma gun and a method for injecting powder into a plume (10) of a thermal spray apparatus (20), the powder injection apparatus (50) including a shroud (55) attachable to an outlet nozzle (15) of a thermal spray apparatus (20) and a substantially smooth and continuous inner wall (60) defining a bowl (63) through which a plume (10) of the thermal spray apparatus (20) travels. At least one port (65) in the inner wall (60) is structured and arranged to receive a powder injection nozzle (70) that injects powder into the plume (10).