Ceramic Sheathed Heater Insulation Structure for Vibration Durability

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Solution Overview

Problem

Ceramic sheathed heaters face reduced durability due to uneven dispersion of insulating powder caused by vibrations, leading to thermal stress and potential contact between the ceramic body and metal tube, resulting in uneven heat dissipation and increased thermal stress.

Innovation Solution

A heater design featuring a ceramic body with a heating resistor, a metal tube, and an insulating member with a tubular portion that contacts both the ceramic body and metal tube, preventing uneven dispersion and reducing thermal stress by absorbing stress and maintaining consistent heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulating powder is used between the ceramic body and metal tube, then insulation is provided, but vibrations cause uneven dispersion leading to contact and thermal stress

Engineering Contradiction:
Improvedurability of ceramic sheathed heaterVSAvoiduniform dispersion of insulating powder
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces an insulating coating layer as an intermediary substance between the ceramic body and metal tube. This coating layer remains stable and maintains consistent insulating properties even under vibration, preventing direct contact between the ceramic body and metal tube while ensuring uniform thermal insulation throughout the assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state of the insulating material from loose powder to a fixed coating layer on the ceramic body surface. This parameter change from particulate to coated form eliminates the dispersion issue caused by vibrations while maintaining the insulating function, thereby improving reliability under vibrational conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If insulating powder is used, then insulation is achieved, but contact between ceramic body and metal tube causes uneven heat dissipation and thermal stress

Engineering Contradiction:
Improvedurability of ceramic sheathed heaterVSAvoidtemperature uniformity of ceramic body surface
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The insulating coating layer acts as a mediator that ensures uniform thermal insulation between the ceramic body and metal tube. By providing a consistent insulating barrier, it prevents localized contact points that would cause uneven heat dissipation and thermal stress, thereby maintaining temperature uniformity across the ceramic body surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If higher temperatures are generated, then heating performance is improved, but thermal stress on ceramic body increases reducing durability

Engineering Contradiction:
Improveheating capability of ceramic sheathed heaterVSAvoiddurability of ceramic sheathed heater
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The insulating coating layer serves as a protective cushion applied beforehand to the ceramic body surface. This pre-applied insulation layer缓冲s thermal stresses that occur during high-temperature operation, preventing direct thermal contact between the ceramic body and metal tube, thereby enabling higher power operation while maintaining durability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 enhances the durability and temperature rise performance of the heater by reducing thermal stress and preventing cracks, ensuring consistent heat generation and improved long-term reliability.

Implementation Method 1

a heating resistor (2) in the ceramic body (1)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an insulating member (4) disposed between the ceramic body (1) and the metal tube (3)

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3101997B1heater
Publication Date: 2018.09.19 KYOCERA CORP
  • EP3101997B1 patent drawingFigure 1
  • EP3101997B1 patent drawingFigure 2
  • EP3101997B1 patent drawingFigure 3

AI summary

A heater including a ceramic body having a columnar shape or a tubular shape, a heating resistor in the ceramic body, a metal tube in which the whole of the ceramic body is disposed, and an insulating member disposed between at least a portion of the ceramic body and the metal tube. The insulating member includes a tubular portion in contact with an outer circumferential surface of the ceramic body at an inner circumferential surface thereof and in contact with an inner circumferential surface of the metal tube at an outer circumferential surface thereof.