Flexible Impeder Sheet for Inner Circumferential Current Suppression
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Solution Overview
Problem
Existing electric-resistance welded pipe manufacturing methods face inefficiencies due to inner circumferential currents that reduce welding efficiency, and conventional inner circumferential current suppression devices require costly modifications or new fabrication when production conditions change.
Innovation Solution
An impedance sheet with ferromagnetic materials disposed on a flexible, heat-resistant insulator that can be wound around the mandrel, providing effective inner circumferential current suppression without modifying existing mandrels or impeder cases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inner circumferential current suppression devices are used, then inner circumferential current is suppressed, but costly modifications or new fabrication are required when production conditions change
Solution Approach 1:
The impeder is divided into multiple independent impeder sheets that can be separately installed and adjusted. Each sheet contains ferromagnetic materials disposed on an insulating sheet, and multiple sheets are stacked and fixed to the mandrel. This segmentation allows flexible adjustment of the suppression device configuration to match different production conditions without requiring complete redesign or fabrication.
Solution Approach 2:
The impeder sheets are designed to be adjustable and reconfigurable on the mandrel. The number of sheets, their positions, and the ferromagnetic material arrangements can be dynamically changed according to production requirements. This dynamic adaptability enables the same suppression device structure to serve multiple production scenarios, eliminating the need for costly modifications when conditions change.
2Productivity
If existing mandrels are modified to improve current suppression, then welding efficiency increases, but maintenance costs and time increase
Solution Approach 1:
The impeder function is separated from the mandrel structure itself and implemented as independent impeder sheets that can be installed on the mandrel. This segmentation allows the impeder components to be easily removed, replaced, or adjusted without affecting the mandrel or requiring complex maintenance operations, thereby reducing maintenance costs and time while maintaining high welding efficiency.
Solution Approach 2:
The impeder sheets are designed as relatively simple, replaceable components rather than permanent mandrel modifications. If wear or damage occurs, the impeder sheets can be easily replaced without costly mandrel repair or fabrication, effectively treating them as consumable or easily replaceable parts that minimize maintenance burden.
3Loss of energy
If ferromagnetic materials are disposed on the mandrel to suppress inner circumferential current, then electricity consumption reduces, but the structure becomes more complex
Solution Approach 1:
The ferromagnetic materials are disposed on thin insulating sheets rather than being integrated into complex three-dimensional structures. These thin-sheet-based impeder components are flexible, easy to install, and do not significantly increase structural complexity. The simple two-dimensional arrangement of ferromagnetic materials on sheets provides effective current suppression while maintaining structural simplicity and ease of manufacturing.
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
Enhances inner circumferential current suppression capability, reduces electricity consumption, increases production rates, and enables production of larger pipes, while minimizing maintenance costs and time.
Implementation Method 1
a high-frequency current is passed through the metal band plate to raise the metal band plate to a melting temperature at the both end portions in the width direction... A ferromagnetic core such as soft ferrite or other ferromagnetic materials is often disposed on an inner surface side of the pipe as an impeder... the current, which tends to flow around an inner circumference of the metal band plate... is a current that does not contribute to welding. Therefore, the above-mentioned impeders are used as a device to suppress the inner circumferential current
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An object of the present invention is to easily increase efficiency of electric-resistance welding at a low cost without modification or new fabrication of a mandrel, impeders and an impeder case that make up a conventional inner circumferential current suppression device. An impedance sheet of the present invention has a sheet that can be freely wound around an outer circumference of a mandrel of an electric-resistance welded pipe manufacturing device, and a plurality of ferromagnetic materials that exhibit insulating properties, which are disposed on the sheet.