Neutrode Stack Cooling for Plasma Guns

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Solution Overview

Problem

Cascade type plasma guns experience high thermal losses due to heat rejection from the plasma arc, limiting the practical length of the neutrode stack and offsetting the advantages of higher voltages and stable arcs, necessitating an optimized cooling structure to prevent thermal damage.

Innovation Solution

The design involves moving water passages away from the plasma gun bore, allowing copper material to distribute heat and increasing average temperatures, with water cooling channels on the outer peripheral surface of disk-shaped bodies, electrically isolating and clamping these bodies to form a thermally optimized neutrode stack with high water velocities, reducing peak temperatures and thermal losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water cooling channels are placed close to the plasma bore, then peak temperatures are reduced, but thermal losses to cooling water increase

Engineering Contradiction:
Improvepeak temperatureVSAvoidthermal loss
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The cooling channels are moved from a radial position near the plasma bore to an axial position at the outer periphery of the neutrode. This spatial repositioning changes the heat transfer path, allowing the copper material to conduct heat axially to the cooling channels, thereby reducing peak temperatures while minimizing direct thermal coupling and thermal losses to the cooling water.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Power

If the neutrode stack length is increased, then higher voltages and stable arcs are achieved, but thermal losses increase

Engineering Contradiction:
Improvegun powerVSAvoidthermal loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The neutrode stack is divided into multiple disk-shaped bodies that can be coaxially aligned and stacked. Each disk can incorporate the optimized peripheral cooling channel design, allowing the stack to be extended in length while maintaining effective cooling throughout. This segmentation enables longer stacks to achieve higher voltages and stable arcs without proportionally increasing thermal losses.

Inventive Principle:
Principle #1Segmentation

3Temperature

If water passages are moved away from the plasma bore, then copper material distributes heat reducing peak temperatures, but water cooling cross section must be reduced

Engineering Contradiction:
Improvepeak temperatureVSAvoidcooling channel design
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling channels are positioned at the outer periphery of the neutrode where the cross-sectional area is larger. This location provides sufficient cooling capacity while allowing the copper material to distribute heat from the plasma bore region to the cooling channels through axial conduction. The peripheral positioning optimizes both heat distribution and cooling efficiency without requiring complex internal channel geometries.

Inventive Principle:
Principle #3Local quality

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 allows for longer neutrode stacks with reduced thermal losses and increased thermal efficiency, maintaining stable gun performance without adverse thermal effects, as demonstrated by a 10% increase in thermal efficiency and minimal decrease in efficiency when doubling the stack length.

Implementation Method 1

allowing the copper material of the neutrode to move the heat reducing peak temperatures

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

water cooling channels on the outer peripheral surface of disk-shaped bodies, electrically isolating and clamping these bodies to form a thermally optimized neutrode stack with high water velocities

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP3597017B1Optimized neutrode stack cooling for a plasma gun
Publication Date: 2023.05.03 OERLIKON METCO (US) INC
  • EP3597017B1 patent drawingFigure 1~2A
  • EP3597017B1 patent drawingFigure 2B~2E
  • EP3597017B1 patent drawingFigure 3~4

AI summary

The design and implementation of a thermally optimized neutrode stack for cascaded plasma guns is provided that reduces the thermal loss to the water while minimizing peak stack temperatures. Optimizing the cooling will permit longer stacks to be used without the penalty of high thermal losses.