Liquid-Cooled Plasma Arc Torch Layout for Tight-Space Cutting

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Solution Overview

Problem

Conventional liquid-cooled plasma arc torches are too wide for maneuvering in tight spaces, such as interior corners of workpieces like wide flange beams, making them difficult to use and increasing the cost of consumables due to larger diameters.

Innovation Solution

A plasma arc torch design with offset fluid conduits and fittings that reduce the torch width by allowing parallel but radially offset fluid channels, coupled with a spring compression plug for electrical connections, facilitating a narrower profile and efficient cooling liquid circulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional liquid cooled plasma arc torches use internal conduits for cooling liquid and plasma gas, then cooling efficiency and plasma generation are improved, but the torch diameter increases making it difficult to maneuver in tight spaces

Engineering Contradiction:
Improvecooling efficiencyVSAvoidtorch diameter
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent implements nested conduits where the plasma gas conduit is positioned inside the cooling liquid conduit. This nested arrangement allows both fluid pathways to occupy the same radial space, significantly reducing the overall torch diameter while maintaining separate, functional cooling and plasma delivery channels.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a conventional side-by-side radial arrangement of conduits to a nested concentric configuration. This dimensional reorganization places conduits in different radial layers (inner and outer), allowing multiple fluid pathways to coexist within a smaller cross-sectional area, thereby reducing torch diameter.

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

2Reliability

If conventional torches use larger diameter consumables to ensure structural integrity and cooling, then reliability is improved, but the cost of consumables increases

Engineering Contradiction:
Improvestructural integrityVSAvoidconsumable cost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The nested conduit structure allows the plasma nozzle and electrode to be positioned concentrically within the cooling liquid pathway. This enables the use of smaller diameter consumables that maintain structural integrity through the nested support structure, reducing material usage and consumable costs.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent changes the dimensional parameters of consumables by utilizing the nested configuration, which allows smaller diameter electrodes and nozzles to be used while maintaining adequate cooling and structural support through the concentric arrangement.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional torches use multiple separate conduits for cooling liquid and plasma gas, then fluid flow efficiency is improved, but the torch width increases

Engineering Contradiction:
Improvefluid flow efficiencyVSAvoidtorch width
Core Design Contradiction:
ProductivityVSArea of moving object

Solution Approach 1:

The patent uses nested concentric conduits where the plasma gas flow path is positioned inside the cooling liquid flow path. This maintains separate, efficient fluid pathways for both gases while reducing the overall torch width by eliminating the need for side-by-side radial arrangement.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent reorganizes fluid conduits from a two-dimensional radial layout to a three-dimensional concentric arrangement, utilizing axial and radial dimensions more efficiently. This allows multiple fluid pathways to occupy the same cross-sectional area without interfering with each other, maintaining flow efficiency while reducing torch width.

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

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

Enables easier handling and cutting in tight spaces with reduced consumable costs by maintaining efficient cooling and plasma gas flow while minimizing the torch's diameter, enhancing operational flexibility and reducing material expenses.

Implementation Method 1

some torches use liquid cooling to transfer the heat away from some of the cutting torch components

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

A spring compression plug electrically connects the pilot arc conductor to the nozzle body

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3820257A1Liquid cooled plasma arc torch
Publication Date: 2021.05.12 LINCOLN GLOBAL INC
  • EP3820257A1 patent drawingFigure 1
  • EP3820257A1 patent drawingFigure 2
  • EP3820257A1 patent drawingFigure 3

AI summary

A plasma arc torch (100, 200, 300) includes a cathode (136) extending along an axis (109) of the torch (100, 200, 300), a pilot arc conductor (246), and a nozzle body (110). A first fluid conduit and second fluid conduit extend parallel to the axis (109) of the torch (100, 200, 300). A first offset fitting includes a first duct coupled to and in fluid communication with the first fluid conduit, and a second duct in fluid communication with the first duct and outwardly radially offset from the first duct and extending away from the first duct in a proximal direction. A second offset fitting includes a third duct coupled to and in fluid communication with the second fluid conduit, and a fourth duct in fluid communication with the third duct and outwardly radially offset from the third duct and extending away from the third duct in the proximal direction. A spring compression plug (168) electrically connects the pilot arc conductor (246) to the nozzle body (110).