Interrupted Induction Welding Band for Uniform Plastic Joint Heating
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Solution Overview
Problem
Induction welding of plastics faces challenges in achieving uniform heat distribution to prevent local overheating, which can damage the plastic materials and reduce the mechanical strength of the welded joints, particularly in district heating pipes where insulation materials can be affected and crystalline structures may form irregularities.
Innovation Solution
A heating means with a band-like structure that interrupts electrical conductivity along its circumference to prevent short-circuit currents, ensuring heating occurs only through eddy currents, thereby achieving homogeneous heat distribution and avoiding local overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a continuous electrically conductive heating medium is used in induction welding, then heating efficiency is improved, but local overheating occurs and heat distribution uniformity deteriorates
Solution Approach 1:
The heating medium is segmented into multiple electrically conductive segments arranged along the welding path, with electrically insulating gaps between them. This segmentation prevents formation of large eddy current loops while maintaining sufficient heating efficiency, thereby achieving both improved power utilization and uniform heat distribution without local overheating.
2Area of stationary object
If the heating medium extends along the full circumference around the inner object, then heating coverage is improved, but short-circuit currents form causing harmful effects
Solution Approach 1:
The circumferential heating medium is divided into multiple conductive segments separated by insulating gaps, preventing continuous current loops while maintaining comprehensive heating coverage through coordinated activation of multiple segments along the welding path.
Solution Approach 2:
Different segments of the heating medium are selectively activated based on local heating requirements along the welding path. The insulating gaps are strategically positioned to prevent short-circuit currents in specific regions while maintaining heating effectiveness through localized segment activation.
3Power
If electromagnetic coupling is achieved through a time-varying magnetic field generated by a coil, then inductive heating is improved, but non-uniform heat distribution occurs leading to local overheating
Solution Approach 1:
The heating medium is segmented into multiple conductive portions with insulating gaps between them, which breaks up large eddy current loops and distributes the electromagnetic energy more uniformly across the heating zone, preventing local overheating while maintaining efficient inductive heating through coordinated segment activation.
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 enhances the homogeneity of heating during the welding process, preventing mechanical weaknesses and maintaining the dimensional stability of the plastic objects, resulting in stronger and more reliable welded joints.
Implementation Method 1
heating it with an alternating electromagnetic field generated by a specially designed generator. In the so-called induction welding of plastic objects, electromagnetic coupling between a magnetic and electrically conductive material and an induction generator is achieved primarily via a time-varying magnetic field generated by a coil of the induction generator
Implementation Method 2
A magnetic and electrically conductive heating medium is introduced between the plastic sleeve and the outer surface of each end section of the two pipes to be joined and inductively heated
Implementation Method 3
ensuring heating occurs only through eddy currents, thereby achieving homogeneous heat distribution and avoiding local overheating
Data Source
Figure 1a~3
Figure 4~6
Figure 7~9
AI summary
The invention relates to a heating means (100-1400) for thermally connecting two objects (760, 770) which each comprise a plastic material, where, during the connection, a first inner object (760) is at least partially surrounded by a second outer object (770) and the heating means (100-1400) at least partially surrounds the first inner object (760) over a complete peripheral course around the first inner object (760), and is arranged between the first inner object (760) and the second outer object (770). The heating means (100-1400) has a strip-type structure (102, 1102, 1302). The strip-type structure (102, 1102, 1302) comprises an auxiliary heating material (220, 1140) that can be inductively heated, the auxiliary heating material (220, 1140) being spatially distributed or arranged along the peripheral course in such a way that electrical conductivity is interrupted at at least one point along the complete peripheral course around the first inner object (760). The invention further relates to an arrangement (785) and a system (890) respectively comprising such a heating means and to a method for thermally connecting two plastic objects (760, 770).