Induction Heating Roller End Temperature Uniformity
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Solution Overview
Problem
Induction heating rollers experience uneven temperature distribution along their axial direction due to non-uniform magnetic flux leakage, leading to inadequate heat generation at the end portions and inefficient heat transfer.
Innovation Solution
Incorporating a heat generating unit with low electric resistivity adjacent to the cylindrical portion and a heat equalizing unit with high heat conductivity to enhance heat transfer and generation at the end portions, ensuring uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat equalizing unit with high heat conductivity is used to transfer heat in the axial direction, then temperature dispersion is reduced, but heat generation at the end portion becomes insufficient
Solution Approach 1:
The patent applies local quality by using different materials with different electric resistivities at different locations. The heat generating unit at the end portion uses a material with lower electric resistivity than the cylindrical portion, enabling localized enhancement of heat generation where magnetic flux leakage is most problematic, while the central portion maintains its original heating characteristics.
Solution Approach 2:
The patent employs composite materials by combining the cylindrical portion made of one material with the heat generating unit made of a different material having lower electric resistivity. This composite structure allows the system to simultaneously achieve adequate heat generation at the end portion (through the low-resistivity material) and maintain overall temperature uniformity (through the heat equalizing unit with high heat conductivity).
2Temperature
If a ring member with low electric resistivity is used to generate heat at the end portion, then temperature dispersion is suppressed, but excessive heat is generated in the ring member
Solution Approach 1:
The patent applies local quality by positioning the heat generating unit with lower electric resistivity specifically at the end portion where magnetic flux leakage causes insufficient heating. This localized approach ensures that additional heat is generated only where needed, preventing excessive heat generation in other portions of the cylindrical structure.
Solution Approach 2:
The patent changes the electric resistivity parameter of the heat generating unit material to be lower than that of the cylindrical portion material. This parameter change enables the heat generating unit to efficiently convert electromagnetic energy to thermal energy at the end portion, addressing the temperature distribution issue without causing excessive energy loss.
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 configuration effectively reduces temperature dispersion along the axial direction of the roller, improving heat distribution and efficiency by directly transmitting heat generated in the heat generating unit to the cylindrical portion via the heat equalizing unit.
Implementation Method 1
When the flow of an alternating current in the coil results in the generation of magnetic flux, an eddy current is generated in a circumferential direction of the cylindrical portion of the roller unit by electromagnetic induction
Implementation Method 2
As a result, heat is generated in the cylindrical portion by Joule heat
Implementation Method 3
an inner circumferential surface of a cylindrical portion is in contact with a heat equalizing unit (this unit is referred to as a heat equalizing member in Patent Literature 1) which is higher in heat conductivity than the cylindrical portion in the axial direction
Data Source
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AI summary
An object of the present invention is to effectively reduce the temperature dispersion of a cylindrical portion of a roller main body in the axial direction of an induction heating roller. An induction heating roller 20 includes a rotatable roller unit 30 and a coil 52. A roller unit 30 includes an outer cylindrical portion 34 (cylindrical portion) extending in an axial direction of the roller unit 30, a roller main body 31 in which the outer cylindrical portion 34 is induction-heated when a current flows in the coil 52, a heat equalizing member 32 which is able to transfer the heat generated in the outer cylindrical portion 34 in the axial direction and which more easily transfers the heat in the axial direction than the outer cylindrical portion 34 does, and a heat generating member 60 which is provided at an end portion of the outer cylindrical portion 34 in the axial direction and which is induction-heated when a current flows in the coil 52. The heat generating member 60 is made of a material which is lower in electric resistivity than a material forming the outer cylindrical portion 34 and a material forming the heat equalizing member 32. The heat generating member 60 is provided to be adjacent to at least one of the outer cylindrical portion 34 and the heat equalizing member 32.