Microwave Heating Control for Plastic Preforms

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Solution Overview

Problem

Existing methods for heating plastic preforms using microwave radiation fail to ensure uniform energy input due to variations in the preforms' material properties, leading to inconsistent heating outcomes.

Innovation Solution

A device with a control system that adjusts microwave energy based on returning energy feedback, using a sensor device and energy adjustment units to regulate the microwave power dynamically during the heating process, allowing for flexible adaptation to different preform conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If microwave energy is applied to plastic preforms using fixed power settings, then the heating process is simple to operate, but uniform heating cannot be guaranteed due to variations in preform material properties

Engineering Contradiction:
Improveheating uniformityVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where a sensor device measures microwave energy returning from the plastic containers, and a control device adjusts the microwave energy impinging on the containers based on this feedback. This closed-loop control ensures uniform heating by continuously adapting to variations in preform material properties and absorbing characteristics.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from fixed power settings to dynamic power adjustment during the heating process. The control device can vary the microwave energy level in real-time based on measured returning energy, allowing the system to adapt to different preform conditions and achieve uniform heating across varying material properties.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the microwave power is set before operation, then the device operation is simple, but the system cannot adapt to different preform conditions during heating

Engineering Contradiction:
Improveadaptability to preform conditionsVSAvoidoperation simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The sensor device continuously monitors microwave energy returning from the containers, providing real-time feedback to the control device. This enables the system to automatically adapt to different preform conditions without requiring manual intervention or pre-setting, maintaining ease of operation while achieving high adaptability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-regulation by using its own sensor feedback to automatically adjust microwave power levels. The control device autonomously adapts the heating parameters based on measured returning energy, eliminating the need for external manual adjustment and simplifying operation while maximizing adaptability to varying preform properties.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If the same microwave energy is applied to all preforms, then the energy input is consistent and simple to control, but heating results vary due to differences in preform absorption characteristics

Engineering Contradiction:
Improveheating consistencyVSAvoidautomatic energy regulation
Core Design Contradiction:
Manufacturing precisionVSExtent of automation

Solution Approach 1:

The control device uses feedback from the sensor device to automatically regulate microwave energy levels. By continuously measuring returning energy and adjusting power output accordingly, the system achieves consistent heating results across preforms with different absorption characteristics without requiring complex manual control procedures.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the microwave energy parameter during the heating process based on measured returning energy. This automatic parameter adjustment ensures consistent heating outcomes by adapting to variations in preform absorption characteristics, achieving both heating consistency and automated control.

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

Ensures uniform and efficient heating of plastic preforms by dynamically adjusting microwave energy input, improving heating consistency and flexibility in response to varying preform properties.

Implementation Method 1

it is also known from WO 2007/131701 A2 to use microwave radiation to heat the plastic preforms

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 2

the device has a sensor device which measures microwave energy returning from the plastic containers

Methodology Applied
Scientific EffectMicrowave radiation detection: Microwave Radiation

Implementation Method 3

a line device which directs the microwaves in the direction of the plastic containers to be heated, this line device being at least partially designed as a waveguide

Methodology Applied
Scientific EffectWaveguide transmission: Waveguide

Data Source

PatentEP2283699B1Apparatus and method for the controlled heating of plastic receptacles
Publication Date: 2016.07.27 KRONES AG
  • EP2283699B1 patent drawingFigure 1
  • EP2283699B1 patent drawingFigure 2~3

AI summary

An apparatus (1) for heating plastic receptacles (10) and particularly plastic parisons (10) with a transport device (2), which transports the plastic receptacles (10) along a predetermined transport path, with a microwave generation device (4), with a routing device (6) which routes the microwaves in the direction of the plastic receptacles (10) which are to be heated, said routing device (6) being at least sectionally in the form of a hollow conductor. In line with the invention, the apparatus (1) has a control device (12) which is in a form such that it controls the microwave energy hitting the plastic receptacles (10) during the heating process.