Induction Heating Coils with Inductance Adjusters
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Solution Overview
Problem
Conventional induction heating methods for steel plates face challenges in maintaining a consistent heating rate, especially near the Curie point, and suffer from energy inefficiency due to high energy losses and difficulties in controlling current flow, which affects the quality of the alloy structure and heating efficiency.
Innovation Solution
The use of a solenoid system with at least three heating coils and inductance adjusters that generate self-induction and mutual induction, allowing for adjustable self-inductance and voltage control, thereby optimizing heating efficiency and maintaining a consistent heating rate by adjusting the cross-sectional area and distance between coils and inductance adjusters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If variable resistors are inserted between heating coils and power source to control magnetizing force, then the magnetizing force of each heating coil can be adjusted, but Joule heat is generated in the variable resistors causing large energy loss
Solution Approach 1:
The patent introduces inductance adjusters as intermediary devices between the power source and heating coils. These inductance adjusters control the current flow through inductive reactance rather than resistance, thereby avoiding Joule heat generation in the control devices while still achieving the desired control of magnetizing force in each heating coil section.
Solution Approach 2:
The patent replaces the electrical resistance-based control system (variable resistors) with an inductance-based control system (inductance adjusters). This substitution changes the control mechanism from resistive to inductive, eliminating the harmful Joule heating effect in the control devices while maintaining the ability to adjust current distribution.
2Ease of operation
If series variable capacitors are used to equalize current in heating coils, then current distribution can be controlled, but high-frequency voltage application is limited due to reduced capacitive reactance
Solution Approach 1:
The patent replaces the capacitor-based current control system with an inductance-based system. Inductors maintain their reactance properties across a broader frequency range compared to capacitors, enabling the heating system to operate effectively at higher frequencies while still achieving proper current distribution among heating coils.
Solution Approach 2:
The patent changes the control parameter from capacitive reactance to inductive reactance. By using inductance adjusters instead of variable capacitors, the system can operate across a wider frequency range because inductive reactance increases with frequency rather than decreasing, providing better adaptability for high-frequency operation.
3Temperature
If large current is flowed through heating coils to heat steel plate to high temperature, then heating to Curie point is achieved, but apparatus design becomes difficult and energy consumption increases
Solution Approach 1:
The patent divides the heating system into multiple independent heating coil sections, each with its own inductance adjuster. This segmentation allows for distributed control of current in each section, enabling the system to achieve high temperatures through coordinated operation of multiple sections rather than requiring excessively high current through a single coil, thereby simplifying the overall apparatus design.
Solution Approach 2:
The patent uses inductance adjusters to change the electrical parameters (reactance) in each heating coil circuit, enabling optimized current distribution. This parameter control allows the system to achieve the required heating temperature with more reasonable current levels by optimizing the electrical characteristics of each heating section.
4Productivity
If variable resistors are used to control current in heating coils, then heating rate can be adjusted, but the rate of heating decreases near Curie point due to energy loss
Solution Approach 1:
The patent replaces resistive current control with inductive current control. By using inductance adjusters instead of variable resistors, the system maintains better heating rates near the Curie point because inductive control devices do not generate Joule heat, preserving more energy for actual heating while still enabling rate adjustment.
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 heating efficiency, reduces energy losses, and maintains a consistent heating rate near the Curie point, improving the quality of the alloy structure and reducing power consumption by optimizing current flow and inductance adjustments.
Implementation Method 1
In the solenoid system, a steel plate is heated by applying, to the plate, a magnetic flux along a longitudinal direction of the steel plate
Implementation Method 2
a heating of the steel plate is conducted... As a heating method of the steel plate, a gas heating, a trans-induction heating and the like
Implementation Method 3
inductance adjusters disposed on electrical pathways electrically connecting each of the heating coils and a power source... and capable of generating self-induction and adjusting self-inductance in the self-induction
Implementation Method 4
each of the inductance adjusters is disposed to cause a generation of mutual induction at least between the inductance adjusters mutually adjacent to one another
Data Source
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AI summary
There is provided an induction heating apparatus which continuously heats a steel plate using a solenoid system. The induction heating apparatus (1) includes: at least three heating coils (10A to 10D) disposed along a longitudinal direction of the steel plate to make the steel plate (2) pass through an inside thereof; and inductance adjusters (12A to 12D) disposed on electrical pathways (11) electrically connecting each of the heating coils and a power source applying a voltage to each of the heating coils and capable of generating self-induction and adjusting self-inductance in the self-induction, in which each of the inductance adjusters is disposed to cause a generation of mutual induction at least between the inductance adjusters mutually adjacent to one another.