Ceramic Honeycomb Outer Wall Induction Drying

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Solution Overview

Problem

Conventional ceramic honeycomb structures for exhaust-gas-cleaning catalytic converters and particulate-matter-capturing filters face issues with cracking and insufficient strength, particularly in large sizes, due to uneven drying and heat shock, leading to reduced durability and production efficiency.

Innovation Solution

The use of a coating material comprising elongated colloidal silica particles, applied to the outer peripheral surface and dried using induction methods like microwaves or RF waves in a moist atmosphere, prevents cracking and enhances the strength of the outer peripheral wall by ensuring uniform drying and bonding with ceramic particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional heating methods are used to dry the coating material, then the drying process can be completed, but cracks occur in the coating material surface due to uneven drying and shrinkage differences

Engineering Contradiction:

Improvedrying speedVSAvoidcrack formation in coating surface

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces conventional thermal conduction heating with induction heating technology. The induction heating apparatus generates a magnetic field that induces eddy currents within the coating material, converting electromagnetic energy directly into heat throughout the material volume simultaneously. This eliminates the surface-to-core heat gradient that causes differential shrinkage and cracking, achieving both fast drying speed and crack-free coating surfaces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating method from external thermal conduction to internal induction heating, fundamentally altering the heat distribution parameters. By controlling the induction heating power and duration, the coating material dries uniformly and rapidly without the shrinkage stress that leads to cracking, thus improving both productivity and manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the outer peripheral wall is made thick to increase strength, then structural integrity improves, but drying shrinkage differences increase leading to more cracks

Engineering Contradiction:

Improveouter peripheral wall strengthVSAvoidcrack formation during drying

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

By replacing conventional heating with induction heating, the patent enables rapid and uniform drying of thick outer peripheral walls. The electromagnetic induction heats the entire thickness of the coating material simultaneously, eliminating the progressive surface-to-core drying gradient. This allows thick walls to be dried without developing internal shrinkage stresses that would cause cracking, thus maintaining both strength and manufacturing precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If heating temperature is elevated to shorten drying time, then productivity improves, but water content difference between surface and inside increases causing cracks

Engineering Contradiction:

Improvedrying timeVSAvoidwater content uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent substitutes external heating with internal induction heating, which generates heat uniformly throughout the coating material volume. This allows the entire coating to dry at the same rate even at elevated temperatures, eliminating the surface-to-core water content gradient. The result is rapid drying (improved productivity) without crack formation (maintained manufacturing precision).

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating mechanism to induction heating, which fundamentally alters the temperature distribution parameters within the coating material. By controlling the induction power and exposure time, uniform high-temperature drying is achieved throughout the coating thickness, maintaining water content uniformity while reducing drying time.

Inventive Principle:

Principle #35Parameter changes

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 effectively suppresses cracking and heat shock resistance, resulting in high-strength ceramic honeycomb structures resistant to handling and operational shocks, improving production efficiency and durability.

Implementation Method 1

drying the coating material to form the outer peripheral wall

Methodology Applied

Scientific EffectInduction heating: Induction Heating

Implementation Method 2

dried using induction methods like microwaves or RF waves

Methodology Applied

Scientific EffectMicrowave heating: Microwave Radiation

Implementation Method 3

ensuring uniform drying and bonding with ceramic particles

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2159209B1Ceramic honeycomb structure and its production method

Publication Date: 2019.11.06 PROTERIAL LTD

Figure 1(a)~2

AI summary

A method for producing a ceramic honeycomb structure comprising a ceramic honeycomb body comprising large numbers of axially extending cells defined by cell walls, and an outer peripheral wall formed on an outer peripheral surface of the ceramic honeycomb body, comprising the steps of applying a coating material comprising colloidal silica having elongated colloid particles to the outer peripheral surface, and drying the coating material to form the outer peripheral wall.