Hybrid Drying Air Recirculation to Prevent Microwave Overheating

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Solution Overview

Problem

Existing microwave drying systems are inefficient and limited by environmental conditions, particularly for wet and cold materials, leading to slow drying processes and potential damage due to overheating, and convective drying is less energy-efficient, making them unsuitable for a wide range of industrial applications.

Innovation Solution

A hybrid drying process involving successive air circulations with varying temperatures and humidities, combined with microwave drying, using a heat pump system to precondition materials, enhancing energy efficiency and preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If microwave drying is applied directly to wet and cold material, then drying speed is improved, but surface overheating and material damage occur

Engineering Contradiction:
Improvedrying speedVSAvoidsurface overheating
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary convective drying to raise the temperature and reduce moisture content of the material surface before applying microwave energy. This preliminary action prevents direct microwave heating of cold, wet material which causes surface overheating and damage, while still enabling fast subsequent microwave drying.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If convective drying is used to precondition material, then surface overheating is prevented, but energy efficiency decreases

Engineering Contradiction:
Improvesurface overheating preventionVSAvoidenergy efficiency
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent merges convective drying and microwave drying into a hybrid system where convective air drying preconditions the material surface, followed by microwave drying for rapid internal moisture removal. This combination leverages the gentle surface heating of convective drying with the high efficiency of microwave drying, achieving both material protection and energy efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements continuous hybrid drying where convective and microwave processes operate in sequence without interruption. The material moves continuously through the drying chamber, receiving convective preconditioning followed immediately by microwave drying, maximizing throughput and energy utilization while preventing material damage.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If microwave power is increased to accelerate drying, then drying speed improves, but energy loss increases

Engineering Contradiction:
Improvedrying speedVSAvoidwaste heat
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies partial microwave power after convective preconditioning rather than using full microwave power from the start. Since the material surface is already warmed and partially dried by convective air, lower microwave power levels are sufficient to complete the drying process, reducing energy consumption and waste heat generation while maintaining high drying speed.

Inventive Principle:
Principle #16Partial or excessive 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

The hybrid drying method accelerates the drying process and improves energy efficiency, making it suitable for a variety of industrial goods, including frozen or insulating materials, while minimizing surface overheating risks.

Implementation Method 1

hybrid drying the product by simultaneously exposing it to microwaves generated by a microwave drying device

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 2

exploiting the thermal effects of the substance absorbing MWs to trigger moisture removal

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 3

air-drying the wet product by circulating a first air circulation... air-drying the first preheated product by circulating a second air circulation

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

the second air circulation comprises the spent air from the first air circulation, which is heated and dehumidified using a heat pump system

Methodology Applied
Scientific EffectHeat pump:

Implementation Method 5

When the internal temperature of a substance rises, material surface moisture evaporation occurs as consequence drying the substance

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4515162B1Hybrid drying of industrial goods
Publication Date: 2026.02.25 MEAM BV
  • EP4515162B1 patent drawingFigure 1
  • EP4515162B1 patent drawingFigure 2~3
  • EP4515162B1 patent drawingFigure 4~6

AI summary

The present disclosure relates to technology for hybrid drying of industrial goods. Specifically, technology is described by means of which the thermal and electrical efficiency of a hybrid drying system can be improved. An aspect of the present disclosure relates to a method for energy-efficient hybrid drying of industrial goods such as raw materials, the drying method comprising the steps: - providing a wet product; - preconditioning the product by successively exposing it to a first air circulation circulated through a first air circulation device, and a second air circulation circulated through a second air circulation device; - hybrid drying the product by simultaneously exposing it to microwaves generated by a microwave drying device and a third air circulation circulated through said microwave drying device; - whereby the second air circulation comprises the spent first air circulation that is warmed up and dehumidified using a heat pump system such that the second air circulation has a lower relative humidity and a higher temperature than the first air circulation; - whereby the first air circulation comprises the spent third air circulation, that is warmed up and humidified in the microwave drying device such that the first air circulation has a higher relative humidity and a higher temperature than the third air circulation.