Microwave Launch Box with Choke Plate for Food Conveyor Ovens

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Solution Overview

Problem

Conventional ovens with microwave generating devices and conveyors face issues such as sensitivity to food load volume, placement, and properties, leading to inefficient cooking and microwave energy leakage, arcing, and coupling, due to unsatisfactory frequency and power delivery, as well as complex and ineffective designs.

Innovation Solution

A food processing machine with a microwave launch box system that emits microwave energy in a lateral direction transverse to the conveyor belt, combined with a convection heating system, and a microwave monitoring detector to prevent energy leakage, using a choke plate and match plate configuration to optimize resonant modes and minimize energy loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional microwave ovens use traditional launch areas and magnetron configurations, then microwave energy can be delivered to the cavity, but microwave energy leakage and arcing occur due to unsatisfactory frequency and power delivery

Engineering Contradiction:
Improvemicrowave energy leakageVSAvoidfrequency and power delivery
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

A choke plate is introduced as an intermediary component between the launch area and the cavity. The choke plate includes a series of progressively larger apertures that act as an impedance matching network, gradually transitioning the microwave impedance from the waveguide to the cavity. This intermediary structure prevents microwave energy leakage and arcing by ensuring smooth energy transfer without sudden impedance mismatches.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The aperture sizes in the choke plate are progressively changed from small to large across the series of openings. This parameter change creates a gradient impedance transformation that optimizes microwave energy delivery. The varying aperture dimensions allow for controlled impedance matching, preventing energy leakage while maintaining reliable frequency and power delivery to the cavity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If microwave energy is delivered with high power to improve cooking efficiency, then cooking speed increases, but microwave energy leakage and arcing increase

Engineering Contradiction:
Improvecooking speedVSAvoidmicrowave energy leakage and arcing
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The choke plate serves as a protective intermediary that enables high-power microwave delivery without causing leakage or arcing. By providing a gradual impedance transition through its series of apertures, it allows high energy levels to be transmitted safely, improving cooking speed while preventing harmful microwave leakage and arcing conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The choke plate structure provides beforehand cushioning by preparing the impedance transition path before high-power microwave energy enters the cavity. The progressive aperture design anticipates and prevents potential arcing and leakage issues before they occur, allowing high-power operation to proceed safely and efficiently.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If traditional oven designs are used, then the structure is simple, but cooking performance is inefficient due to sensitivity to food load volume, placement, and properties

Engineering Contradiction:
Improvecooking efficiencyVSAvoidoven structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The choke plate introduces controlled parameter changes in the form of progressively varying aperture sizes. This parameter variation optimizes microwave energy distribution throughout the cavity, improving cooking efficiency by reducing sensitivity to food load characteristics. The graduated aperture design creates more uniform energy patterns that accommodate different food volumes and placements more effectively than traditional uniform structures.

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 solution ensures efficient cooking of food products by optimizing microwave energy distribution and preventing energy leakage, resulting in improved cooking performance and reduced energy loss, while maintaining safe microwave levels.

Implementation Method 1

a microwave launch box system configured to emit microwave energy into a cavity in a lateral direction transverse to the longitudinal direction to thereby further heat the food product

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 2

emit microwave energy into the cavity... to thereby further heat the food product

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 3

a convection heating system for heating air in the cavity such that heated air heats the food product as the food product is conveyed through the cavity

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

using a choke plate and match plate configuration to optimize resonant modes and minimize energy loss

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3720284B1Ovens with metallic belts and microwave launch box assemblies for processing food products
Publication Date: 2023.10.11 ALKAR RAPIDPAK INC
  • EP3720284B1 patent drawingFigure 1
  • EP3720284B1 patent drawingFigure 2
  • EP3720284B1 patent drawingFigure 3

AI summary

In certain examples, a food processing machine for processing a food product includes a housing defining a cavity, a conveyor with a belt comprising metal for conveying the food product through the cavity in a longitudinal direction, and a convection heating system for heating air in the cavity such that heated air heats the food product as the food product is conveyed through the cavity. A microwave launch box system is configured to emit microwave energy into the cavity in a lateral direction transverse to the longitudinal direction to thereby further heat the food product as the food product is conveyed through the cavity.