Inductive Welding Coil Array for Plastic Pipe Heating Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Induction welding of plastic pipes faces inefficiencies due to unwanted heating of internal metallic structures within the pipes, which affects the quality and energy efficiency of the welding process, as the magnetic field penetrates deeply into the plastic pipe, heating ferromagnetic or eddy current-absorbing materials inside.
Innovation Solution
A coil arrangement with multiple individual coils, each having a smaller cross-sectional area, is used to control the magnetic field penetration depth, allowing for targeted heating of the plastic surfaces while minimizing the heating of internal metal layers by shaping the magnetic field lines and using a heating agent with ferromagnetic particles embedded in a plastic matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single large coil is used for induction welding, then the welding area is covered effectively, but the magnetic field penetrates deeply into the pipe interior causing unwanted heating of internal metal structures
Solution Approach 1:
The single large coil is divided into multiple smaller individual coils arranged in an array. Each small coil generates a magnetic field with limited penetration depth, preventing unwanted heating of internal metal structures while collectively covering the entire welding area through their combined arrangement.
2Object-affected harmful factors
If multiple small coils are used, then the magnetic field penetration depth is reduced, but the device complexity increases
Solution Approach 1:
The coil system is segmented into multiple independent small coils that can be individually controlled. This segmentation allows precise control of magnetic field penetration depth while the modular nature of the small coils makes the overall system more manageable and less complex than a single large coil system.
Solution Approach 2:
The array of small coils serves multiple functions simultaneously: each coil independently controls local magnetic field penetration, collectively they cover the entire welding area, and their arrangement allows flexible adaptation to different pipe configurations and welding requirements.
3Ease of manufacture
If the magnetic field penetrates deeply into the pipe, then the heating process is simpler, but the energy efficiency decreases due to heating of non-target materials
Solution Approach 1:
By segmenting the coil into multiple small units, the magnetic field penetration is naturally limited to shallow depths at each location. This eliminates the need for complex shielding mechanisms while preventing energy waste on heating internal metal structures that should not be heated.
Solution Approach 2:
Each small coil in the array provides localized heating with controlled penetration depth appropriate for its specific position. This local control ensures that energy is concentrated where needed (at the welding interface) and does not waste energy heating internal structures, thereby improving overall energy efficiency.
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 quality and efficiency of the induction welding process by reducing unwanted heating of internal metal structures, allowing for higher frequency usage and achieving more homogeneous and stable welds with improved spatial homogeneity of the magnetic field.
Implementation Method 1
an electromagnetic coupling between a magnetic and electrically conductive material and an induction generator occurs 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 inserted between the plastic sleeve and the outer surface of one end section of each of the two pipes to be joined and inductively heated
Implementation Method 3
using a heating agent with ferromagnetic particles embedded in a plastic matrix
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A description is given of a heating device (110) for thermally connecting a pipe (150), which comprises a first plastics material, to a sleeve (160), which comprises a second plastics material and which surrounds at least a portion of the pipe (150), wherein an inductively heatable heating means (170) is located between the pipe (150) and the sleeve (160) and/or is integrated in the pipe (150) and/or the sleeve (160). The heating device (110) has a coil arrangement (120), which can be excited by a generator (140) and comprises a first coil (121), which has at least one complete turn within a first cross-sectional area, and a second coil (122), which is electrically coupled to the first coil (121) and has at least one complete turn within a second cross-sectional area. The first cross-sectional area is different from the second cross-sectional area. Also described are a heating system (100) with such a heating device (110) and also a method for thermally connecting a pipe (150) to a sleeve (160).