Induction Coil Temperature Detection Without Internal Sensors
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Solution Overview
Problem
Existing induction heated roll apparatuses face challenges in accurately detecting the temperature of the induction coil due to thermal insulation by insulators and contact state variations, leading to reduced detection accuracy and potential sensor deterioration or disconnection.
Innovation Solution
An induction heated roll apparatus that calculates the temperature of the induction coil without a sensor inside the roll main body by intermittently applying DC voltage to determine the resistance value and using stored relational data to derive the coil's temperature, utilizing a control circuit to minimize AC current effects and suppress biased magnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is embedded in the induction coil to monitor temperature, then the temperature detection capability is improved, but the insulator thermally insulates the sensor causing deterioration in detection accuracy
Solution Approach 1:
The temperature sensor is extracted from the induction coil structure. Instead of embedding the sensor inside the coil, the patent uses a separate temperature detection mechanism that measures the coil's temperature indirectly through its effect on surrounding components or through thermal coupling with a separately positioned sensor, thereby eliminating the insulator interference problem.
Solution Approach 2:
An intermediary substance or structure is introduced between the induction coil and the temperature sensor. This intermediary provides thermal coupling that overcomes the insulator's thermal barrier, allowing accurate temperature measurement without direct contact between the sensor and the coil windings.
2Measurement precision
If a temperature sensor is embedded in the induction coil, then temperature monitoring is enabled, but contact state variations cause detection accuracy to change
Solution Approach 1:
The temperature sensor is extracted from direct contact with the induction coil windings. The sensor is positioned in a fixed location relative to the coil assembly, measuring temperature through a stable thermal path that does not depend on variable contact conditions between the sensor and coil components.
Solution Approach 2:
The patent creates a stable thermal field environment for the sensor by providing consistent thermal coupling conditions. The sensor is positioned where it experiences a stable thermal gradient or isothermal condition relative to the coil, making the measurement independent of contact state variations.
3Measurement precision
If a temperature sensor is embedded in the induction coil, then temperature detection is achieved, but deterioration due to temperature and disconnection due to mechanical external force occur
Solution Approach 1:
The temperature sensor is extracted from the high-temperature, high-stress environment inside the induction coil assembly. The sensor is positioned in a cooler, mechanically more stable location while still being thermally coupled to the coil, thereby reducing thermal deterioration and mechanical disconnection risks.
Solution Approach 2:
The patent provides thermal and mechanical protection for the temperature sensor by positioning it in a protected location with reduced exposure to extreme temperatures and mechanical forces. The sensor is shielded from direct thermal stress and mechanical vibration that would cause deterioration or disconnection.
4Measurement precision
If a temperature sensor is embedded in the induction coil, then temperature monitoring is enabled, but disassembly of the induction heated roll apparatus is required to replace the sensor
Solution Approach 1:
The temperature sensor is extracted from the internal coil structure and repositioned in an externally accessible location. This allows the sensor to be replaced or serviced without disassembling the induction heated roll apparatus, significantly improving ease of repair and maintenance.
Solution Approach 2:
The temperature sensing function is segmented from the main induction coil assembly into a separate, independently accessible component. This modular arrangement allows the sensor to be replaced without affecting the coil structure or requiring disassembly of the roll apparatus.
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 accurate temperature detection of the induction coil without internal sensors, reducing maintenance complexities and improving reliability by using a DC voltage application, resistance value calculation, and temperature calculation mechanism.
Implementation Method 1
a magnetic flux generating mechanism that is provided inside the roll main body and includes an iron core and an induction coil wound around the iron core
Implementation Method 2
a resistance value calculation part that calculates a resistance value of the induction coil from the DC voltage applied by the DC voltage application part and DC current flowing through the induction coil when applying the DC voltage
Data Source
Figure 1
Figure 2
AI summary
The present invention intends to detect the temperature of an induction coil without providing a temperature sensor inside a roll main body, and includes: a DC voltage application part 61 that controls a DC power supply 7 to intermittently apply DC voltage to the induction coil 32; a resistance value calculation part 62 that calculates a resistance value of the induction coil 32 from the DC voltage applied by the DC voltage application part 61 and DC current flowing through the induction coil 32; a relational data storage part 63 that stores relational data indicating a resistance value - temperature relationship between the resistance value of the induction coil 32 and the temperature of the induction coil 32; and a coil temperature calculation part 64 that calculates the temperature of the induction coil 32 from the resistance value obtained by the resistance value calculation part 62 and the resistance value - temperature relationship indicated by the relational data.