Radiative Heating Device for Polymer Powders Using Wavelength Shifting Aperture

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Solution Overview

Problem

Current methods for heating polymer powders in powder coating processes are inefficient, particularly due to poor absorption of electromagnetic radiation by uncolored polymers and the risk of dust explosions from contact with hot surfaces, and existing radiative heating technologies lack rapid temperature control and wavelength specificity.

Innovation Solution

A device with a radiation source having a maximum output in the 0.78 - 2.5 µm wavelength range, combined with an aperture that absorbs and re-emits radiation in a shifted wavelength range of 2.5 - 4.8 µm, allowing for efficient heating and rapid temperature regulation of polymer powders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If electromagnetic radiation in the visible and near-IR range is used to heat polymer powders, then heating speed is improved, but absorption efficiency deteriorates because uncolored polymers poorly absorb radiation in this wavelength range

Engineering Contradiction:
Improveheating speedVSAvoidradiation absorption efficiency
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent changes the wavelength parameter of the radiation source from visible/near-IR (0.78-2.5 μm) to mid-IR (2.5-4.8 μm) range. This parameter change enables uncolored polymers to effectively absorb radiation through their natural molecular vibrations, resolving the contradiction between heating speed and absorption efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional convection heating with radiative heating using mid-IR radiation. This substitution eliminates the need for prolonged exposure that causes charge loss, while maintaining effective energy transfer through direct molecular absorption of electromagnetic radiation in the optimal wavelength range.

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

2Temperature

If conventional convection heating is used to melt and crosslink powder particles, then complete heating is achieved, but charging time is excessive causing charge loss and reduced adhesion

Engineering Contradiction:
Improveparticle temperatureVSAvoidheating time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The patent substitutes convection heating with mid-IR radiative heating. This enables rapid temperature increase of powder particles without prolonged exposure, maintaining electrostatic charge integrity while achieving complete melting and crosslinking through direct molecular absorption of radiation energy.

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

3Ease of operation

If radiation sources with fast temperature control are used, then rapid regulation is achieved, but radiation maximum may not be in the optimal wavelength range for polymer absorption

Engineering Contradiction:
Improvetemperature control responsivenessVSAvoidradiation wavelength匹配
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent specifies using mid-IR radiation sources (2.5-4.8 μm wavelength range) that naturally align with polymer absorption characteristics. This parameter selection ensures both optimal energy absorption by uncolored polymers and rapid temperature control capability, resolving the contradiction between wavelength matching and control responsiveness.

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

The device enables rapid and efficient heating of polymer powders with improved temperature control and reduced energy consumption, preventing dust explosions by avoiding direct contact with hot surfaces and optimizing radiation absorption.

Implementation Method 1

A device with a radiation source having a maximum output in the 0.78 - 2.5 µm wavelength range

Methodology Applied
Scientific EffectElectromagnetic radiation: Radiation

Implementation Method 2

an aperture that absorbs and re-emits radiation in a shifted wavelength range of 2.5 - 4.8 µm

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Data Source

PatentEP3305418B1Device for heating polymeric powder by radiation in powder coating process
Publication Date: 2022.11.02 EVONIK OPERATIONS GMBH
  • EP3305418B1 patent drawingFigure 1

AI summary

The present invention relates to a device for heating powder particles, comprising a radiation source (1), a housing (2), and an aperture (4). The radiation source (1) has its maximum radiant power in the wavelength range of 0.78–2.5 µm. The aperture (4) has an absorption coefficient of at least 0.8 in the wavelength range of 0.78–2.5 µm.