Induction Heating Roller Layout for Uniform Axial Temperature
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Solution Overview
Problem
Induction heating rollers face challenges in achieving uniform surface temperature distribution along the axial direction due to unequal heat generation and dissipation, leading to excessive heat generation at the axial end portions, which is exacerbated by the use of carbon steel fixing rings that facilitate excessive eddy currents.
Innovation Solution
Incorporating a heat equalizing member with higher thermal conductivity than the roller main body, a fixing ring made of carbon steel, and strategically positioning a magnetic member to divert magnetic flux away from the fixing ring, thereby reducing eddy currents and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat equalizing member with higher thermal conductivity is provided inside the roller main body, then the temperature distribution uniformity is improved, but the device complexity increases
Solution Approach 1:
The heat equalizing member is inserted into the hollow interior space of the roller main body, nesting one component inside another. This allows the heat equalizing function to be added without increasing the overall roller dimensions, resolving the contradiction between temperature uniformity and device complexity.
Solution Approach 2:
The heat equalizing member acts as an intermediary thermal conductor between the heating coil and the roller main body, redistributing heat axially to achieve uniform temperature distribution without requiring fundamental changes to the heating system architecture.
2Temperature
If the roller main body thickness is increased to provide a heat equalizing member, then the temperature distribution uniformity is improved, but the heating efficiency deteriorates due to increased heat capacity
Solution Approach 1:
The heat equalizing member is nested within the existing roller main body hollow space, so no additional radial thickness is required. This maintains the original heat capacity while achieving temperature uniformity through internal heat redistribution.
Solution Approach 2:
Instead of increasing physical thickness to improve heat distribution, the invention uses a thermal conduction-based heat equalizing member that actively redistributes heat through high thermal conductivity materials, replacing the passive approach of increased mass.
3Temperature
If a carbon steel fixing ring is used to fix the heat equalizing member, then the heat equalizing function is improved, but excessive heat generation occurs at the base end portion due to excessive eddy currents
Solution Approach 1:
The harmful eddy current path is extracted or interrupted by introducing a non-magnetic or low-magnetic conductivity material at the fixing ring position, preventing excessive heat generation while preserving the heat equalizing function of the inner member.
Solution Approach 2:
An intermediary material with appropriate magnetic properties is introduced at the fixing ring position to mediate between the magnetic flux and the heat equalizing member, preventing excessive eddy currents while allowing the heat equalizing function to operate.
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
The solution achieves more uniform temperature distribution along the axial direction of the roller, reducing excessive heat at the end portions and improving the efficiency of the induction heating process.
Implementation Method 1
As an alternating current flows through the coil, eddy currents are induced in the roller main body due to electromagnetic induction
Implementation Method 2
the roller main body is heated by Joule heating (that is, heat is generated in the roller main body by induction heating)
Implementation Method 3
the heat equalizing member extending in the axial direction and having a heat conductivity higher at least than that of the roller main body
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
In order to suppress the generation of heat in a fixing ring provided in an induction heating roller, this induction heating roller 20 is provided with a roller unit 30 and a heater 50 which comprises a coil 52 arranged inside of the roller unit 30 in the radial direction. The roller unit 30 comprises: a roller main body 31 which has an outer tube part 34 which is inductively heated by magnetic flux that, generated by current flowing through the coil 52, passes through the roller unit 30 in the axial direction; a heat equalizing unit 32 which comprises a heat equalizing member 41 that contacts the inner peripheral surface 34b of the outer tube part 34, extends in the axial direction, and at least has a higher thermal conductivity than that of the inner peripheral surface 34b; a fixing ring 33 which fixes the roller main body 31 and the heat equalizing unit 32 and is provided in a manner such that the axial base end of the outer tube part 34 and the axial base end of the heat equalizing unit 32 are in contact; and a first magnetic member 46 which is arranged radially between the outer tube part 34 and the coil 52 and is arranged proximally of the center of the outer tube part 34 and distally of the fixing ring 33.