Inductive Bimetal Switch Testing for Fast Localized Heating

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Solution Overview

Problem

Existing methods for testing bimetal switches in heating devices, such as using hot air from a fan, are inefficient as they unnecessarily heat surrounding components and are slow, lacking precision and automation.

Innovation Solution

The implementation of an induction coil to inductively heat the bimetal switch, allowing for targeted and rapid heating, actuation, and function detection, eliminating the need for separate control units and enabling automated testing by interrupting electrical signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If hot air from a fan is used to heat the bimetal switch for testing, then the bimetal switch can be heated to test its functionality, but surrounding components are unnecessarily heated and the testing process becomes slow and inefficient

Engineering Contradiction:
Improvebimetal switch temperatureVSAvoidsurrounding component heating
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical fan-based hot air heating system with an induction coil that uses electromagnetic induction to heat the bimetal switch directly. This substitution eliminates the need for mechanical air movement and thermal convection, providing targeted heating without affecting surrounding components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The induction coil is positioned to provide localized heating specifically at the bimetal switch location. The electromagnetic field is concentrated at the target area, ensuring that only the bimetal switch is heated while surrounding components remain at normal temperatures, thus resolving the contradiction between effective heating and avoiding harmful thermal effects.

Inventive Principle:
Principle #3Local quality

2Reliability

If hot air from a fan is used to heat the bimetal switch, then the switch can be tested, but the testing process is slow and lacks precision

Engineering Contradiction:
Improveswitch function detectionVSAvoidtesting duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The induction heating system replaces the slow thermal convection process with rapid electromagnetic heating. The induction coil can heat the bimetal switch to the required temperature much faster than a fan-based hot air system, significantly reducing testing duration while improving temperature control precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating method from thermal convection to electromagnetic induction, fundamentally altering the heating parameters. This enables precise control of heating rate and temperature, allowing the bimetal switch to reach test temperature quickly and accurately, thereby improving both reliability and speed of testing.

Inventive Principle:
Principle #35Parameter changes

3Extent of automation

If a separate control unit is used to test the bimetallic switch, then the testing function can be implemented, but the device complexity increases

Engineering Contradiction:
Improvetesting automationVSAvoidcontrol unit requirements
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The device's existing control unit is designed to perform multiple functions, including both normal device operation and bimetal switch testing. The control unit manages the induction coil activation, monitors the testing process, and detects switch actuation signals, eliminating the need for a separate dedicated testing control unit and reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the testing control functions with the device's existing control unit. The control unit is enhanced to handle both operational control and testing sequences, integrating the induction coil control, temperature monitoring, and switch actuation detection into a single unified control system, thereby avoiding additional complexity from separate control units.

Inventive Principle:
Principle #5Merging (Combining)

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 method allows for efficient, rapid, and precise testing of bimetal switches during manufacturing or maintenance, avoiding unnecessary heating of surrounding components and increasing automation, ensuring accurate functionality recognition.

Implementation Method 1

an induction coil (26) is placed in and/or on the device, in particular the heating device, by means of which a bimetal (14) of the bimetallic switch (12) is inductively heated

Methodology Applied
Scientific EffectInductive heating: Induction Heating

Implementation Method 2

The bimetallic switch (12) comprises a bimetal (14) and a switch (16)

Methodology Applied
Scientific EffectBimetallic bending: Bi-Metallic Strip

Data Source

PatentEP3857243B1Method for testing a bimetallic switch
Publication Date: 2024.05.15 BOSCH TERMOTECHA
  • EP3857243B1 patent drawingFigure 1
  • EP3857243B1 patent drawingFigure 2

AI summary

The invention relates to a method for testing a bimetallic switch (12) of a device (11), in particular a heating device (11). An induction coil (26) is attached in and/or on the device (11), and the induction coil is used to inductively heat a bimetal (14) of the bimetallic switch (12). The invention also relates to a device (11), in particular a heating device (11), comprising a bimetallic switch (12), and a device for testing the bimetallic switch (12), said devices being designed to test the bimetallic switch (12) using such a method.