Gas-Cooled Plasma Torch Electrode Cooling Cavity Design

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Solution Overview

Problem

Gas-cooled plasma cutting torches have shorter wearing part lifespans compared to water-cooled counterparts, leading to increased operational costs and reduced productivity due to frequent part replacements and thermal stress.

Innovation Solution

An electrode design for gas-cooled plasma cutting torches featuring an elongated body with a cavity extending over half its length, incorporating a cooling tube and strategically positioned openings for enhanced cooling, allowing for improved heat dissipation and increased service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If gas-cooled plasma cutting torches are used instead of water-cooled ones, then the design is simpler and easier to use, but the service life of wearing parts is shorter

Engineering Contradiction:
Improveease of useVSAvoidservice life of wearing parts
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The electrode is divided into multiple functional sections along its length, with each section having specific cooling openings positioned at different locations. This segmentation allows targeted cooling of different electrode regions, improving overall cooling efficiency and extending service life while maintaining the simple gas-cooled design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the electrode are provided with different cooling characteristics through strategically positioned openings. The first, second, and third sections have varying opening configurations to address local thermal stress variations, optimizing cooling where most needed while preserving the simplicity of gas cooling

Inventive Principle:
Principle #3Local quality

2Reliability

If gas cooling is used instead of liquid cooling, then there is no risk of short circuits from coolant, but larger volume flows are required to achieve acceptable cooling

Engineering Contradiction:
Improverisk of short circuitVSAvoidvolume flow of gas
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The cooling approach transitions from axial cooling alone to a multi-dimensional cooling strategy with openings distributed across different sections and orientations of the electrode. This spatial distribution of cooling openings improves gas cooling efficiency, reducing the required volume flow while maintaining reliable operation without liquid coolant risks

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

3Duration of action of stationary object

If the electrode has enhanced cooling features, then service life is extended, but device complexity increases

Engineering Contradiction:
Improveservice life of electrodeVSAvoidelectrode structure complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

Multiple cooling functions are merged into a single electrode structure by integrating cooling openings directly into the electrode body across different sections. This consolidation achieves enhanced cooling and extended service life without adding separate cooling components, thereby limiting complexity increase

Inventive Principle:
Principle #5Merging (Combining)

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 enhanced cooling mechanism significantly extends the service life of the electrode and maintains cutting quality over a longer period, reducing operational costs and improving productivity.

Implementation Method 1

a cavity in the electrode body extends from the open end of the electrode body towards the closed end and is in fluid communication with the outer side of the electrode body radially relative to the longitudinal axis via at least one opening in its wall

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The enhanced cooling mechanism significantly extends the service life of the electrode and maintains cutting quality over a longer period

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3639631B1Electrodes for gas- and liquid-cooled plasma torches, systems comprising these electrodes and a cooling tube, and plasma torch with these electrodes
Publication Date: 2024.07.03 KJELLBERG STIFTUNG
  • EP3639631B1 patent drawingFigure 1
  • EP3639631B1 patent drawingFigure 2
  • EP3639631B1 patent drawingFigure 2a

AI summary

The invention relates to an electrode (30) for an especially gas-cooled plasma torch (10), in particular plasma cutting torch, the electrode comprising: an elongated electrode body (30b) with an open end (34) and a closed end (33), said ends defining a longitudinal axis L, and an emission insert (31) in the closed end (33), a cavity (32; 32a, 32b) extending in the electrode body (30b) from the open end (34) of the electrode body towards the closed end (33), said cavity fluidically communicating with the outer face (37) of the electrode body which is radial with regard to the longitudinal axis, via at least one opening (32c, 32d) in its wall (30a) or in the front solid portion of the closed end (33). The invention further relates to a system consisting of said electrode and cooling tube, to a gas conducting unit, a plasma torch comprising same, a method for conducting gas in a plasma torch and a method for operating the plasma torch.