Multi-Coil Induction Welding for Plastic Pipe-to-Bushing Joints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Induction welding of plastic pipes faces inefficiencies due to unwanted heating of internal metallic structures by the induction magnetic field, which reduces welding quality and energy efficiency.
Innovation Solution
A heating device with a divided coil arrangement, featuring two coils with different cross-sectional areas, is used to minimize magnetic penetration depth and prevent heating of internal metal layers, allowing for more precise control of the electromagnetic field to focus heating on the intended area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single coil arrangement is used for induction welding, then the heating coverage is sufficient, but the magnetic field penetrates too deep into the pipe interior causing unwanted heating of internal metallic structures
Solution Approach 1:
The single coil arrangement is divided into multiple individual coils (first coil, second coil, and further coils) that are arranged along the longitudinal axis. Each coil has a smaller cross-sectional area and generates a magnetic field that is confined to a limited depth, preventing penetration into internal metallic structures while maintaining adequate heating coverage through the combined effect of multiple coils.
2Object-affected harmful factors
If the coil cross-sectional area is reduced to minimize magnetic penetration depth, then internal structures are protected from heating, but the heating efficiency decreases
Solution Approach 1:
Multiple individual coils with smaller cross-sectional areas are combined along the longitudinal axis to form a coil arrangement that achieves both objectives: each coil limits magnetic field penetration depth to protect internal structures, while the combined effect of all coils maintains sufficient heating efficiency for the welding process.
3Area of stationary object
If a single large coil is used, then the magnetic field covers the entire welding region, but the field homogeneity is poor and energy is wasted on internal structures
Solution Approach 1:
The welding region is divided into multiple zones, each served by an individual coil. This segmentation creates more homogeneous magnetic fields in each local zone compared to a single large coil, while the overlapping fields of adjacent coils ensure complete coverage of the entire welding region.
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 metallic structures, enabling higher frequency usage and improving the homogeneity of the magnetic field for better welding connections.
Implementation Method 1
an electromagnetic coupling is effected between a magnetic and electrically conductive material and an induction generator substantially via a magnetic field, which is variable in time and which is generated by a coil of the induction generator
Implementation Method 2
an inductively heatable heating means is located between the pipe and the bushing and/or integrated in the pipe and/or the bushing
Implementation Method 3
the induction magnetic field generated by the primary coil penetrates relatively far into the interior of the plastic pipe
Data Source
AI summary
Described is a heating device for thermally connecting a pipe, which has a first plastic material, to a bushing, which has a second plastic material, and which surrounds at least a section of the pipe, wherein an inductively heatable heating means is located between the pipe and the bushing and/or integrated in the pipe and/or the bushing. The heating device has a coil arrangement, which is excitable by a generator, and which has a first coil, which has at least one complete winding within a first cross-sectional area, and a second coil, which is electrically coupled to the first coil, and which has at least one complete winding within a second cross-sectional area. The first cross-sectional area is different from the second cross-sectional area. Furthermore, a heating system having such a heating device as well as a method for thermally connecting a pipe to a bushing are described.