Inductive Heating Coil System for Uniform Surface Temperature
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Solution Overview
Problem
Existing heating techniques, such as inductive and resistive heating, struggle to achieve uniform and controlled heating over large or complex surfaces, leading to inefficiencies and quality issues in industrial applications.
Innovation Solution
A coil system with a closed conduit configuration that induces a voltage and current in a heated element, allowing for precise geometric control and uniform heating of plane, curved, and complex surfaces, combining inductive and resistive heating principles for efficient energy use and rapid heating/cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If inductive heating is used to rapidly heat the outermost layer of a tool surface, then heating speed is improved, but uniform temperature distribution across the surface deteriorates
Solution Approach 1:
The heating system is divided into multiple independently controllable coil units (first coil unit, second coil unit, third coil unit) that can be controlled separately. This segmentation allows each coil to be adjusted individually to achieve uniform temperature distribution across the entire tool surface while maintaining rapid heating capability.
Solution Approach 2:
Different regions of the tool surface are heated with different characteristics by assigning specific coil units to specific zones. The coil units can be controlled to provide locally optimized heating patterns, allowing rapid heating in some areas while maintaining temperature uniformity in others, thus resolving the contradiction between heating speed and temperature uniformity.
2Power
If resistive heating is used with large current to heat the workpiece, then heating effect is improved, but electrical contact reliability deteriorates due to local overheating
Solution Approach 1:
An intermediate heating element (the tool surface itself acting as a heating element) is introduced between the electrical contact points and the workpiece. The electrical contacts are made at the edges of the tool where current flows through the tool material to the heating surface, distributing the current path and avoiding direct contact at the heating zone, thus preventing local overheating at contact points while maintaining high heating power.
3Manufacturing precision
If heating is applied to thick workpieces to achieve even temperature, then temperature uniformity is improved, but heating time increases due to heat conduction requirements
Solution Approach 1:
The heating is extracted from a volumetric process to a surface-specific process. By using induction heating coils positioned close to the tool surface, the heating effect is concentrated at the surface where needed, rather than requiring heat to conduct through the entire thickness of the workpiece. This allows rapid surface heating with uniform temperature distribution without the time penalty of volumetric heating.
4Area of stationary object
If conventional heating methods are used for large tool quantities, then heating coverage is improved, but energy efficiency deteriorates due to heat conduction requirements
Solution Approach 1:
The heating approach transitions from volumetric heating (heating through the thickness of the workpiece) to surface heating (heating only the tool surface). By using induction coils positioned in close proximity to the tool surface and configuring them to induce currents specifically in the tool material, the system achieves wide area coverage with high energy efficiency, as energy is deposited directly at the target surface rather than being lost to heat conduction through the entire workpiece volume.
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 solution enables fast, precise, and energy-efficient heating of various surface geometries, reducing cycle times and improving product quality by achieving uniform temperature profiles across complex surfaces, while allowing for integrated cooling and versatile tool usage.
Implementation Method 1
The magnetic field of the coil unit is arranged to induce a voltage in the electric current conductor and the element, the induced voltage creating an electric current in the closed conduit
Implementation Method 2
Resistive heating works in a way that a large current is driven through the workpiece which becomes hot
Data Source
Figure 1a~1b
Figure 2a
Figure 2b
AI summary
An apparatus for controllable heating is provided comprising at least one coil system (110) with at least one coil unit (111) connected to a power source, where the coil unit (111) is arranged to create a magnetic field. The apparatus further comprises at least one electric current conductor (120) which is arranged at least partly around said coil unit (111), and at least one element (130) which is configured to be heated and which is connected to the electric current conductor (120) in such a way that the electric current conductor (120) and the element (130) form a closed conduit. The magnetic field of the coil unit (111) is arranged to induce a voltage in the electric current conductor (120) and the element (130), where the induced voltage creates an electric current in the closed conduit, and where the element (130) is configured to be heated by the electric current.