Multi-Flame Burner With Inclined Flame Axes For Pipe Preheating
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Solution Overview
Problem
Existing multi-flame burners used for preheating large-diameter pipes in welding operations face challenges such as hydrogen embrittlement, increased hardness, and cold crack formation due to inadequate heat distribution, which can lead to thermal damage and high maintenance costs.
Innovation Solution
A multi-flame burner design with offset connection pipes and burner heads, where the flame axes of adjacent burner heads are inclined divergently, allowing for concentrated heat application near the welded seam without overheating the burner heads, and a method for preheating workpieces using a fuel mixture like acetylene and oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If concentrated heat is introduced into the region close to the welded seam, then preheating effectiveness is improved, but the burner heads are thermally damaged
Solution Approach 1:
The burner system is divided into multiple burner heads (at least three) arranged around the pipe, each with its own flame axis. This segmentation allows the heat input to be distributed across multiple zones rather than concentrated at a single point, enabling effective preheating while preventing any single burner head from overheating and suffering thermal damage.
Solution Approach 2:
Each burner head is positioned and angled to deliver heat to a specific local region of the pipe near the welded seam. The flame axes are inclined at different angles relative to the pipe axis, creating localized heating zones that collectively cover the required area without concentrating excessive heat on any single burner head.
2Temperature
If conventional multi-flame burners are used for preheating, then heating capability is provided, but hydrogen embrittlement and cold crack formation occur due to inadequate heat distribution
Solution Approach 1:
The burner heads are arranged asymmetrically around the pipe with flame axes inclined at different angles. This asymmetric configuration creates a more uniform heat distribution pattern around the welded seam area, preventing cold spots that would lead to hydrogen embrittlement and cold crack formation, while achieving the required preheating temperature.
Solution Approach 2:
The burner heads are positioned in three-dimensional space around the pipe circumference, with flame axes oriented at different angular positions and inclinations. This spatial arrangement in multiple dimensions ensures comprehensive heat coverage of the welded seam region, eliminating inadequate heating zones that cause material defects.
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 design effectively reduces the risk of cold cracks and hydrogen embrittlement by controlled heat distribution, minimizing burner damage and maintenance needs, while allowing for efficient heating of large-diameter pipes with reduced operational burdens.
Implementation Method 1
generate at least one burner flame directed along a respective flame axis when supplied with a fuel... operated with acetylene and oxygen-containing fuel mixtures
Implementation Method 2
concentrated heat must be introduced into the region close to the welded seam... concentrated heat introduction
Data Source
AI summary
A multi-flame burner is disclosed with burner heads, which are set up to generate at least one burner flame directed along a respective flame axis when supplied with a fuel, wherein the flame axes of respectively adjacent burner heads are inclined relative to each other. A method for preheating a workpiece, in particular a pipe or large-diameter pipe, using a multi-flame burner is also disclosed.