Heating Coil Resonance for Electrofusion Weld Quality
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Solution Overview
Problem
Existing methods for non-destructive testing of weld seams in electrofusion welding are complex and often compromise the strength and leak resistance of the pipes, particularly due to the need for integrated conductor coils and test channels.
Innovation Solution
The method utilizes a heating coil already present in the welding zone to excite the weld seam with varying frequency and amplitude signals, determining resonance signals to assess the quality of the weld without additional tools, by comparing them to reference values, thereby evaluating the weld seam's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If integrated conductor coils and test channels are added for non-destructive testing, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The heating coil originally designed solely for welding is made to serve dual purposes: it functions as both the welding heat source and the excitation source for non-destructive testing. By applying an excitation signal to the heating coil, it generates mechanical vibrations in the welded workpiece, enabling quality assessment without requiring separate test coils or channels.
Solution Approach 2:
The heating coil serves itself by utilizing its own structure and position to perform testing functions. The coil's inherent electrical properties allow it to be excited and generate vibrations that propagate through the welded joint, enabling the system to test its own weld quality without external specialized testing equipment.
2Measurement precision
If test channels are provided in the weld zone, then measurement capability is improved, but strength and leak resistance deteriorate
Solution Approach 1:
The testing function is extracted from the welding process itself rather than being integrated through physical modifications to the workpiece. By using the heating coil as the excitation source, the method eliminates the need for test channels that would compromise the structural integrity and leakage resistance of the welded pipe.
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 allows for a simple, non-destructive assessment of weld seams using existing equipment, ensuring the integrity of the weld without compromising the pipe's strength or leak resistance, as it utilizes the heating coil as a vibration resonator to analyze the weld's resonant frequencies.
Implementation Method 1
Excitation of a heating coil in a weld zone containing the weld seam between at least two components welded together via the heating coil with at least one excitation signal with an excitation signal amplitude and an excitation signal frequency or an excitation signal frequency sweep with varying excitation signal frequency to cause an oscillation
Data Source
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AI summary
Method for the non-destructive testing of a weld seam formed using electrofusion welding, the method comprising the steps of: - Exciting (100) a heating coil in a weld zone containing the weld seam between at least two components welded together via the heating coil with at least one excitation signal having an excitation signal amplitude and an excitation signal frequency or an excitation signal frequency sweep with varying excitation signal frequency to oscillation; - Varying (200) the excitation signal with respect to the excitation signal frequency and/or the excitation signal amplitude with which the heating coil is excited and determining (300) at least one resonance signal, in particular a resonance signal amplitude or a resonance signal frequency, of the weld zone or of the welded components;- Comparing (400) the determined resonance signal with at least one reference value for the resonance signal of the weld zone or of the welded components, concluding that a weld is proper if the deviation between the determined resonance signal and the at least one reference value does not exceed a maximum value. A corresponding arrangement is further described.