Shielding Gas Pressure Control for Full-Penetration Weld Profiles

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Solution Overview

Problem

In welding processes, particularly for flowmeters and other components where full penetration is required, achieving precise weld penetration without excessive penetration is challenging, especially when accessing the inner regions is limited, leading to high re-working rates due to uneven weld joints.

Innovation Solution

An apparatus that controls weld penetration by providing a shielding gas to the inner region of a workpiece, regulating its pressure to limit penetration, using a gas supply and pressure gauge in communication with the inner region, and adjusting the gas pressure via a valve, with system electronics managing the pressure within a predetermined range to maintain optimal weld profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If full weld penetration is required for precision welding in flowmeters, then weld strength is improved, but the risk of excessive penetration increases requiring re-working

Engineering Contradiction:
Improveweld joint strengthVSAvoidweld re-working rate
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The system incorporates real-time monitoring of weld penetration depth and uses this feedback to dynamically adjust the shielding gas flow rate to the inner region. When penetration approaches the desired threshold, the gas flow increases to prevent excessive penetration, ensuring full penetration is achieved without over-penetration and eliminating the need for re-working

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The shielding gas is pre-positioned within the conduit interior before welding begins. This preliminary placement of the gas barrier allows the weld to achieve full penetration while being immediately protected from excessive penetration, preventing the need for re-working rather than correcting it after the fact

Inventive Principle:
Principle #10Preliminary action

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 solution ensures precise weld penetration, reducing the need for re-working by maintaining the weld joint within acceptable limits, enhancing the integrity and accuracy of welds in complex geometries like flowmeters and conduits.

Implementation Method 1

a pressure of the shielding gas provides a force that limits weld penetration

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Data Source

PatentEP3326743B1Apparatus for controling a weld penetration profile with application of shielding gas in an inner region of a workpiece
Publication Date: 2021.07.28 MICRO MOTION INC
  • EP3326743B1 patent drawingFigure 1
  • EP3326743B1 patent drawingFigure 2
  • EP3326743B1 patent drawingFigure 3

AI summary

A method of controlling a weld penetration profile on a workpiece (306) having an outer region and an inner region is described. The method comprises the step of applying energy to the outer region of the workpiece with a welder (302) to produce a weld pool (304). The method also comprises the steps of penetrating the workpiece (306) such that the weld pool (304) spans between the outer region and inner region, and also applying a shielding gas to the inner region at a pressure that provides a force that limits weld penetration. A corresponding apparatus is also defined.