External Shielding Gas Sensor for Arc Welding Torch

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Solution Overview

Problem

Existing methods for measuring protective gas in arc welding lack precision and efficiency, often requiring lengthy measurements, increased gas consumption, and impaired torch accessibility, with limited assessment of gas properties and quality impact on weld seams.

Innovation Solution

A sensor system positioned at a distance simulating real welding conditions, connected to an evaluation unit, measures gas properties like oxygen content, allowing for precise adjustment of gas supply and quality assessment, while minimizing contamination and gas consumption, and enabling automated measurement with optional wireless data transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a suction pump is used to extract gas for analysis as in DE 26 01 251 A1, then gas concentration can be measured, but the torch accessibility is impaired and gas consumption increases

Engineering Contradiction:
Improvegas concentration measurementVSAvoidtorch accessibility
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts only the essential measurement function from the complex suction pump system. By using a simple sensor to detect gas properties directly in the protective gas envelope, it removes the need for mechanical extraction devices, thereby maintaining torch accessibility while achieving precise gas concentration measurement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical suction pump system with a sensor-based detection system. Instead of mechanically extracting gas samples, the sensor directly detects gas properties (such as oxygen content) in the protective gas envelope, eliminating mechanical complexity and improving ease of operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a color indicator is used for inert gas measurement as in DD 239 744 A1, then oxygen content can be detected, but measurement time increases and the indicator must be replaced after each measurement

Engineering Contradiction:
Improveoxygen content detectionVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the chemical color indicator system with an electronic sensor system. The sensor provides immediate electronic detection of oxygen content, eliminating the time required for color change observation and indicator replacement, thereby significantly reducing measurement time while maintaining detection precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The sensor system is designed to be reusable and self-sustaining, eliminating the need for single-use color indicators that must be replaced after each measurement. The sensor can continuously or repeatedly measure gas composition without requiring replacement, reducing both time loss and operational complexity.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If sensors are positioned close to the torch for measurement, then gas properties can be detected, but the risk of contamination and damage to the measuring device increases

Engineering Contradiction:
Improvegas property detectionVSAvoidmeasuring device contamination risk
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a protective intermediary structure (such as a sampling probe or protected sensor housing) that allows the sensor to detect gas properties near the torch without direct exposure to the harsh welding environment. This intermediary protects the sensor from contamination and damage while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If gas supply is increased to improve protective gas effect, then weld seam quality improves, but gas consumption and costs increase

Engineering Contradiction:
Improveweld seam qualityVSAvoidgas consumption
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent implements a feedback control system where sensor measurements of gas properties (such as oxygen content in the protective gas envelope) are used to adjust gas supply parameters. When the protective gas effect is sufficient, gas flow is reduced; when contamination is detected, gas flow is increased. This maintains weld seam quality while minimizing gas consumption and costs.

Inventive Principle:
Principle #23Feedback

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 provides quick, precise, and practical evaluation of protective gas quality, optimizing welding processes, reducing gas costs, and ensuring high-quality weld seams by accurately assessing gas properties and wear part condition.

Implementation Method 1

at least one sensor for measuring at least one gas property of the protective gas, in particular its oxygen content

Methodology Applied
Scientific EffectGas property measurement:

Data Source

PatentEP2121234B1Device and method for shielding gas measurement
Publication Date: 2017.06.21 FRONIUS INT GMBH
  • EP2121234B1 patent drawingFigure 1
  • EP2121234B1 patent drawingFigure 2
  • EP2121234B1 patent drawingFigure 3

AI summary

The invention relates to a device and a method for measuring shielding gas (8) used in an arc welding process by analyzing the shielding gas (8) emerging from a gas nozzle (27) of a torch (10), wherein at least one sensor (31) is arranged in an external measuring device (30) for the shielding gas analysis. For rapid, exact and practical determination and correspondingly effective evaluation of the shielding effect of the shielding gas, for the shielding gas analysis at least one sensor (31) is arranged in an external measuring device (30) and positioned at a distance (38) from the torch (10) that is essentially the same as the distance (38) between the torch (10) and a workpiece (16) in a welding process, and so the emergence and effect of the shielding gas (8) of an actual welding process can be simulated and at least one sensor (31) is connected to an evaluation unit (32) and via the latter to a welding device (1).