Dual Waveguide Microwave Applicator for Uniform Heating

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Solution Overview

Problem

Existing microwave heating devices for chemical processes face challenges in maintaining effective heating conditions for samples with varying permittivity or volume, requiring complex control systems and increasing manufacturing costs, especially when heating small sample volumes.

Innovation Solution

A self-adjusting microwave heating device with a dual waveguide system, where the applicator space is distributed across two adjacent waveguides, allowing the electromagnetic field distribution to adapt to changing permittivity conditions without moving parts, ensuring efficient microwave energy absorption across varying sample volumes and filling levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a single-mode applicator is used to heat small sample volumes, then higher field intensities and more even energy distribution are achieved, but impedance matching deteriorates when sample permittivity or volume changes

Engineering Contradiction:
Improveheating uniformityVSAvoidimpedance matching
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The applicator cavity is divided into two separate waveguide sections (first and second waveguides) that are arranged at an angle to each other. This segmentation allows each waveguide to be independently optimized for different sample conditions, resolving the contradiction between maintaining heating uniformity and adapting to impedance changes when sample permittivity or volume varies.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If complex control systems are added to maintain effective heating conditions for varying samples, then heating effectiveness is maintained, but manufacturing costs increase

Engineering Contradiction:
Improveheating effectivenessVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The dual waveguide configuration enables the applicator to automatically adapt to different sample conditions through its geometric design. The angle between waveguides and their respective field distributions self-adjust based on sample placement and properties, eliminating the need for external control systems while maintaining heating effectiveness across varying sample volumes and permittivities.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the applicator space is concentrated in one location, then the structure is simpler, but heating uniformity deteriorates for small sample volumes

Engineering Contradiction:
Improveapplicator structureVSAvoidheating uniformity
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

Instead of concentrating the applicator space in a single location, the invention distributes it across two waveguide sections arranged at an angle in three-dimensional space. This spatial distribution creates overlapping electromagnetic field patterns that provide uniform heating for small samples while maintaining structural simplicity through the elegant geometric arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 achieves efficient and uniform heating of small sample volumes with varying permittivity and filling levels, reducing manufacturing costs by eliminating the need for sophisticated control systems and maintaining high microwave absorption rates, while allowing for pressurizable vessels and precise temperature control.

Implementation Method 1

Microwave-assisted chemistry is essentially based on the dielectric heating of substances capable of absorbing microwave radiation, which is subsequently converted into heat.

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 2

a source of microwave radiation, a first waveguide for guiding said microwave radiation to an applicator space

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Data Source

PatentEP2244529B1Device for Heating a Sample by Microwave Radiation
Publication Date: 2019.04.03 ANTON PAAR GMBH
  • EP2244529B1 patent drawingFigure 1
  • EP2244529B1 patent drawing

AI summary

The present inventions concerns device for heating a sample by microwave radiation comprising a source of microwave radiation, a first waveguide for guiding said microwave radiation to an applicator space adapted to receive said sample to be heated, wherein said applicator space is defined by a terminal portion of said first waveguide and an initial portion of a second waveguide extending from said terminal portion of said first waveguide and being arranged at an angle with respect to said first waveguide.