Plasma Nozzle Shroud Gas Layout to Prevent Anode Build-Up
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Solution Overview
Problem
Existing thermal spray processes, particularly plasma spray processes, suffer from material build-up on the anode due to re-condensation and deposition of feedstock material, leading to inefficiencies and disruptions in the coating process.
Innovation Solution
The introduction of shroud gas inlets positioned upstream and downstream of the material injection port within the anode, forming a protective gas layer that prevents material deposition on the anode walls, enhancing the efficiency and longevity of the spray process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If internal injection is used to improve heat transfer efficiency, then material is efficiently vaporized and melted, but material build-up occurs on the anode wall causing clogging
Solution Approach 1:
A shroud gas flow (intermediary substance) is introduced between the plasma jet and the anode wall to prevent direct contact of feedstock material with the anode surface. This mediator carries the material away from the anode wall into the hot plasma zone for efficient heating while preventing deposition on the anode, thus maintaining both heat transfer efficiency and process reliability
Solution Approach 2:
The harmful effect of material deposition on the anode wall is extracted and removed by introducing a shroud gas flow that captures the feedstock material before it can condense on the anode surface, preventing clogging while maintaining internal injection configuration
2Reliability
If shroud gas flow is introduced to prevent material build-up, then anode reliability is improved, but device complexity increases
Solution Approach 1:
The shroud gas flow serves multiple functions simultaneously: it prevents material deposition on the anode wall, directs material into the hot plasma zone for efficient heating, and protects the anode from thermal damage. This multi-functionality reduces the need for additional separate components, minimizing the increase in device complexity
Solution Approach 2:
The shroud gas flow is integrated with the existing plasma generation system, combining the protective function with the material delivery function in a single unified approach, rather than adding separate complex subsystems
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 reduces material build-up, extends anode lifetime, and maintains consistent coating quality by directing feedstock material towards the plasma jet's hottest zone, improving heat transfer and process efficiency.
Implementation Method 1
forming a protective gas layer that prevents material deposition on the anode walls
Implementation Method 2
The material thus melts or vaporizes in this hot plasma and is at the same time accelerated towards the substrate by the plasma stream
Implementation Method 3
This configuration reduces material build-up, extends anode lifetime, and maintains consistent coating quality by directing feedstock material towards the plasma jet's hottest zone, improving heat transfer and process efficiency
Implementation Method 4
Under certain conditions described in EP Patent 2 439 306, the material is transferred partially or completely into the vapor phase. This process regime is referred to as plasma spray physical vapor deposition (PS-PVD)
Data Source
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AI summary
Plasma nozzle includes a nozzle body arranged to engage with a thermal spray gun. The nozzle body includes an axial through bore having up-stream input orifice and a down- stream nozzle exit, at least one material injector positioned between the up-stream input orifice and the nozzle-exit, said at least one material injector being configured to introduce a feedstock material into a gas flow passing through the axial through bore and at least one gas injector configured to introduce a shroud gas flow into the axial through bore and being located at a position up-stream of said at least one material injector.