Water-Cooled Induction Coil for Uniform Heating of Long Workpieces
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Solution Overview
Problem
Existing induction coils for heating long steel workpieces face issues with short lifespan due to mechanical forces at low frequencies and uneven heating from the outside to the inside, leading to deformation and inefficient temperature distribution.
Innovation Solution
A copper-made induction coil with ceramic tube, insulation, and cooling system, featuring water-cooled copper plates and rollers, designed to heat from the center to the outside, with multiple frequency zones for optimized heating and extended lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low frequency is used for induction heating, then heating of the center is improved, but mechanical forces increase causing coil deformation and shorter lifespan
Solution Approach 1:
The induction coil is divided into multiple independent sections along its length, with each section capable of being supported individually. This segmentation allows the coil to better withstand mechanical forces at low frequencies without undergoing deformation, as each segment can flex independently rather than the entire coil structure being stressed uniformly.
Solution Approach 2:
The patent provides for more support holders than the minimum required, placing holders at frequent intervals along the coil length. This excessive provision of support structures ensures that even at low frequencies where mechanical forces are highest, the coil receives sufficient support to prevent deformation while maintaining the ability to heat the center effectively.
2Temperature
If heating is performed from outside to inside, then surface heating is achieved, but corner overheating and deformation occur
Solution Approach 1:
The patent inverts the conventional heating approach by using low frequency induction heating that prioritizes center heating over surface heating. This inversion of the heating sequence allows the workpiece to be heated from the inside out, preventing corner overheating and deformation while achieving the desired temperature distribution.
3Productivity
If high frequency is used for induction heating, then surface heating is faster, but edges overheat and melt
Solution Approach 1:
The patent changes the frequency parameter from high to low, operating the induction coil at frequencies between 50-600 Hz instead of conventional high frequencies. This parameter change fundamentally alters the heating pattern from surface-dominated to center-dominated, achieving both faster overall heating and prevention of edge overheating.
4Adaptability or versatility
If furnace temperature is maintained for continuous operation, then production flexibility is improved, but energy consumption increases and decarburization occurs
Solution Approach 1:
The induction heating system provides self-service heating directly at the workpiece location without requiring a continuously operating furnace. The coil heats only when needed and only the specific workpiece being processed, eliminating the need to maintain furnace temperature during non-production periods and thereby reducing energy consumption and decarburization.
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
Enables faster, uniform heating of long workpieces with reduced edge overheating, improved mechanical properties, and extended coil lifespan by minimizing mechanical stress and enhancing temperature control.
Implementation Method 1
induction coil for heating long workpieces
Implementation Method 2
The heating process in induction devices for heating workpieces depend on the frequency of power voltage used for powering the inductor
Implementation Method 3
The coil and the protective copper plates are cooled with cooling water
Implementation Method 4
The components of the coil according to the invention are cooled with water
Data Source
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AI summary
The invention relates to an induction coil for heating long workpieces, said induction coil comprising a connection for connection to a transformer, a central part of the coil connected with the connection through a connecting pipe and a protective copper plate on each end of the central part, a holder for the induction coil between the central part of the coil and the connection, and transport cylinders for moving the workpiece through the coil. Said central part of the coil comprises: - a ceramic tube (31), - dilatation insulation (32) surrounding the ceramic tube (31), - an induction coil (33) made from copper, wrapped by insulation tape and protected with an insulating varnish, - two protective copper plates (5) cooled with water, - a layer of thermal concrete (34), - and panelling (35) made from water-resistant plywood surrounding said induction coil (33) with the layer of thermal concrete (34). For longer life span connections (22), protective copper plates (5) and the induction coil (33) are provided with channels for cooling water, which is pumped from a reservoir with a suitable pump.