Coating Film Drying Using Infrared and Cool Air

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Solution Overview

Problem

Existing coating film drying techniques using radiant heat often result in surface regions being hardened before the inside regions, leading to vapor entrapment and negative effects on surface quality, and require longer drying times, especially when using water-based paints.

Innovation Solution

A method and apparatus that utilize a combination of infrared heaters and warm-air blow ports, where warm air is blown at a temperature less than the hardening temperature of the coating film to prevent premature hardening of the surface, and a drying furnace with a heating zone and a cooling zone to control the flow volumes and temperatures of air and radiant heat for efficient drying.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If radiant heat is used to dry the coating film, then the drying speed is improved, but the surface region hardens earlier than the inside region causing vapor entrapment and surface quality deterioration

Engineering Contradiction:
Improvedrying speedVSAvoidsurface quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies different thermal conditions to different regions of the coating film. The surface region is cooled by blowing air at temperatures below the hardening temperature to prevent premature hardening, while the inside region is heated by radiant heat to maintain drying speed. This local differentiation of thermal treatment resolves the contradiction between fast drying and surface quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies preliminary cooling action to the surface region before it hardens. By blowing air at temperatures below the hardening temperature, the surface is preemptively protected from hardening too early, preventing the harmful effect of vapor entrapment before it occurs.

Inventive Principle:
Principle #9Preliminary anti-action

2Object-affected harmful factors

If water-based paint is used to reduce volatile organic solvents, then environmental performance is improved, but the drying time is increased

Engineering Contradiction:
Improvevolatile organic solvents reductionVSAvoiddrying time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent changes the temperature parameter of the air blown onto the coating surface. By using air at temperatures below the hardening temperature rather than high-temperature air, the drying process for water-based paint is accelerated without causing surface hardening issues, thus reducing drying time while maintaining environmental benefits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a two-stage drying process: first, radiant heat is applied to heat the coating film rapidly; second, cool air is blown to prevent surface hardening. This periodic alternation of heating and cooling actions enables efficient drying of water-based paint without extending the overall drying time.

Inventive Principle:
Principle #19Periodic action

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 approach allows for rapid and efficient drying of the coating film without compromising surface quality, reducing the drying time while maintaining the effectiveness of radiant heat, and ensuring the coating film is dried within a shorter period without pinholes or irregularities.

Implementation Method 1

emit radiant rays to a coating film on an exterior panel of a workpiece to heat and dry the coating film by means of radiant heat

Methodology Applied
Scientific EffectRadiant heat: Thermal Radiation

Implementation Method 2

the radiant rays can be absorbed in the coating film efficiently and evenly, and radiant heat generated by the absorption of the radiant rays allows the coating film to be rapidly heated up

Methodology Applied
Scientific EffectAbsorption of radiant rays: Absorption (EM radiation)

Implementation Method 3

blow hot air against a coating film on an exterior panel of a box-shaped workpiece

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

accelerate water evaporation from a surface of the coating film to facilitate drying the coating film

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 5

supplying cooling air to a surface region of the coating film in the cooling zone

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP2060863B2Coating film drying method and coating film drying apparatus
Publication Date: 2020.09.02 TAIKISHA LTD
  • EP2060863B2 patent drawingFigure 1
  • EP2060863B2 patent drawingFigure 2
  • EP2060863B2 patent drawingFigure 3

AI summary

Disclosed is a method and apparatus for drying a coating film (4a) on an exterior panel of a box-shaped workpiece (4), wherein radiant rays, and warm air having a temperature less than a hardening temperature of the coating film (4a), are supplied simultaneously and directly to the coating film (4a). The method and apparatus of the present invention can dry the coating film (4a) on the exterior panel of the workpiece (4) within a relatively short period of time, without causing a negative effect on a surface quality of the coating film (4a).