Plasma Torch Nozzle Angular Shield Flow Injection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Plasma arc torches face challenges in achieving effective cooling of the nozzle and protection from slag reflection while maintaining stable plasma gas flow, particularly with large nozzle exit orifice length to diameter ratios, which can lead to instability and reduced performance in cutting and piercing metallic materials.

Innovation Solution

A plasma arc torch design featuring a conical nozzle and corresponding conical shield with angular shield flow impingement, optimizing the ratio of columnar and perpendicular fluid components to stabilize the plasma gas flow and enhance nozzle cooling and slag protection, with adjustable angles and vent holes for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If shield gas is injected at 90 degrees to impinge plasma gas flow, then nozzle cooling and slag protection are improved, but plasma gas flow stability deteriorates

Engineering Contradiction:
Improvenozzle cooling effectivenessVSAvoidplasma gas flow stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent changes the injection angle parameter of the shield gas from 90 degrees to an angular range of 10-45 degrees relative to the plasma gas flow direction. This parameter modification simultaneously achieves effective nozzle cooling and maintains plasma flow stability by optimizing the balance between cooling effectiveness and flow disturbance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces adjustable injection angles and flow rates for the shield gas, allowing dynamic optimization of the shielding effect. The system can adapt the shield gas parameters based on operating conditions to maintain both cooling effectiveness and plasma stability under varying workloads.

Inventive Principle:
Principle #15Dynamics

2Duration of action of stationary object

If shield gas flow is used for nozzle cooling and slag protection, then nozzle durability is improved, but plasma arc performance deteriorates due to flow disruption

Engineering Contradiction:
Improvenozzle durabilityVSAvoidcutting and piercing performance
Core Design Contradiction:
Duration of action of stationary objectVSProductivity

Solution Approach 1:

The patent optimizes the shield gas injection angle parameter to range between 10-45 degrees, which reduces flow disruption compared to 90-degree injection. This parameter change allows the system to maintain nozzle durability through effective cooling while preserving plasma arc concentration and cutting/piercing performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies shield gas cooling selectively at the nozzle periphery rather than uniformly across the entire plasma jet. This localized cooling approach protects the nozzle from thermal damage and slag erosion while minimizing interference with the central plasma arc that performs the cutting and piercing functions.

Inventive Principle:
Principle #3Local quality

3Productivity

If large nozzle L/D ratio is used, then cutting speed and thickness capability are improved, but plasma flow stability deteriorates

Engineering Contradiction:
Improvecutting speed and thickness capabilityVSAvoidplasma gas flow stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent modifies the shield gas injection angle parameter to 10-45 degrees, which creates a more favorable flow environment for large L/D ratio nozzles. This angle optimization reduces turbulence and flow separation in long nozzles, maintaining plasma stability even when high L/D ratios are used for increased cutting speed and thickness capability.

Inventive Principle:
Principle #35Parameter changes

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 achieves effective nozzle cooling, protection from slag reflection, and stable ionized plasma gas flow, enabling efficient cutting, piercing, and marking of metallic materials with increased nozzle durability and reduced maintenance needs.

Implementation Method 1

The shield gas 5 or other fluid passes through the one or more passageways to cool the nozzle

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The torch produces a plasma arc, which is a constricted ionized jet of a plasma gas with high temperature and high momentum

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 3

a pilot arc is first generated between the electrode (i.e., cathode) and the nozzle (i.e., anode)

Methodology Applied
Scientific EffectElectric Arc: Electric Arc

Data Source

PatentEP1878324B2Plasma arc torch providing angular shield flow injection
Publication Date: 2017.08.23 HYPERTHERM INC
  • EP1878324B2 patent drawingFigure 1~2
  • EP1878324B2 patent drawingFigure 3~4A
  • EP1878324B2 patent drawingFigure 4B~4C

AI summary

Plasma arc torches described herein include a torch tip with an improved nozzle that provides angular shield flow injection. In particular, the nozzle provides angular/conical impingement of a fluid (e.g., a shield gas) on an ionized plasma gas flowing through a plasma arc torch. Some of the torch tips described herein include a nozzle with a conical external shape combined with a shield with complementing internal geometry to form the angular fluid flow. As a result, a plasma arc torch including the improved nozzle have the benefits of a stabilized ionized plasma gas flow together with enhanced nozzle cooling and protection from reflecting slag during torch use.