Plasma Arc Torch Nozzle O-Ring Groove and Centering Design

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Solution Overview

Problem

Existing nozzles for liquid-cooled plasma arc torches face issues where the O-ring can be damaged during installation into the nozzle holder, and the contact area for cooling liquid is limited, affecting cooling efficiency and centering.

Innovation Solution

A nozzle design featuring a cylindrical section with a groove for the O-ring at the rear end, a conically tapered section for centering, and additional grooves or channels for improved coolant contact, reducing O-ring damage and enhancing cooling and centering within the nozzle holder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the groove for the O-ring is located directly at the rear end of the nozzle, then the O-ring can be easily positioned, but the O-ring can be damaged when inserted into the nozzle holder

Engineering Contradiction:
ImproveO-ring positioningVSAvoidO-ring integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The groove for the O-ring is positioned in the first portion at a distance from the rear end of the nozzle, allowing the O-ring to be pre-positioned and secured before the nozzle is inserted into the holder. This preliminary positioning prevents the O-ring from being damaged during insertion, as it is already protected by the nozzle body structure.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the cooling liquid contact area is limited to the rear, then the nozzle structure is simpler, but the cooling efficiency is reduced

Engineering Contradiction:
Improvenozzle structureVSAvoidcooling efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The invention extends the cooling liquid contact area from merely the rear region to include the first portion of the nozzle body where the O-ring groove is located. This dimensional extension of the cooling contact zone allows coolant to flow along a longer path and contact a larger surface area, significantly improving cooling efficiency without substantially increasing structural complexity.

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

3Ease of operation

If the difference between outer diameters D12 and D11 is small, then the nozzle fits more tightly in the holder, but the centering surface area is reduced

Engineering Contradiction:
Improvenozzle fittingVSAvoidcentering accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The nozzle body is divided into distinct portions: a first portion with a larger outer diameter D12 that provides an extended centering surface for accurate alignment with the holder, and a second portion with a smaller outer diameter D11 that creates a clearance gap. This segmentation allows the centering function and fitting function to be separated, enabling both accurate centering and easy fitting to be achieved simultaneously.

Inventive Principle:
Principle #1Segmentation

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 design allows for the O-ring to be positioned without damage and increases the coolant contact area, improving cooling efficiency and centering of the nozzle, especially during high-power operations.

Implementation Method 1

a centering surface for a nozzle holder which defines an outer diameter D12 of the body and a second portion adjoining it towards the front end of the body and having an axial length L2, which has an axial stop surface for the nozzle holder at the boundary with the first section

Methodology Applied
Scientific EffectGeometric constraint: Geometry

Implementation Method 2

the contact area between the cooling liquid and the nozzle is limited to the rear

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

liquid-cooled plasma arc torch

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3054749B1Nozzle for a plasma arc torch
Publication Date: 2021.04.21 KJELLBERG STIFTUNG
  • EP3054749B1 patent drawingFigure 1
  • EP3054749B1 patent drawingFigure 2
  • EP3054749B1 patent drawingFigure 3

AI summary

Nozzles for a liquid-cooled plasma arc burner head, as well as an arrangement consisting of a nozzle holder and such a nozzle and plasma arc burner head and plasma arc burner with the same/the same.