Container Parison Hybrid Heating for Faster, Lower-Energy Forming
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Solution Overview
Problem
Existing heating methods for plastic preforms, such as infrared heating, suffer from low efficiency and slow production rates, with infrared heating being only 25% efficient and requiring high electrical energy consumption.
Innovation Solution
A combined heating process using infrared and microwave radiation in two successive phases, where preforms are first preheated with infrared radiation and then subjected to microwave heating, optimizing temperature differences and energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If infrared heating is used to heat preforms, then the heating process is simple and well-controlled, but the heating efficiency is low (25% electrical power consumption)
Solution Approach 1:
The patent combines infrared heating and microwave heating into a single hybrid heating system. The infrared lamps provide initial heating and temperature distribution, while microwave generators are integrated into the same heating zone to provide additional heating energy. This merging of two heating technologies allows the system to achieve higher overall efficiency while maintaining the simplicity of the infrared heating process.
Solution Approach 2:
The heating system uses a composite approach by combining different heating mechanisms (infrared radiation and microwave radiation) within the same processing zone. The preform is simultaneously exposed to both infrared and microwave energy sources, creating a composite heating effect that overcomes the limitations of using either method alone.
2Device complexity
If infrared heating is used to heat preforms, then the implementation is simple, but the production rate is slow
Solution Approach 1:
By merging infrared heating with microwave heating in the same processing zone, the system maintains the simplicity of infrared implementation while adding the rapid heating capability of microwaves. This combination enables faster heating cycles without requiring a completely new system design, thus improving production rate while keeping device complexity manageable.
Solution Approach 2:
The system employs periodic or pulsed microwave heating cycles interspersed with infrared heating phases. The microwave generators operate in periodic bursts to provide intense heating when needed, while infrared heating provides continuous background heating. This periodic action allows the system to achieve rapid heating speeds without requiring continuous high-power microwave operation, maintaining implementation simplicity.
3Loss of energy
If microwave heating is applied to preforms, then heating efficiency increases, but temperature differences between cold and hot zones are amplified
Solution Approach 1:
The system performs preliminary infrared heating before applying microwave heating. This preliminary action ensures that the preform reaches a baseline temperature and develops initial temperature distribution patterns. When microwave heating is subsequently applied, the preform is already in a state that promotes more uniform temperature distribution, preventing excessive temperature differences from developing.
Solution Approach 2:
The system dynamically adjusts heating parameters by varying the intensity and duration of both infrared and microwave heating based on real-time temperature feedback. The control system modifies power levels and heating cycle durations to maintain temperature uniformity while maximizing heating efficiency, preventing the amplification of temperature differences.
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
This method significantly increases heating efficiency, reduces electrical energy consumption, and accelerates production rates by maintaining and amplifying temperature differences between cold and hot zones, ensuring precise shaping of containers.
Implementation Method 1
A fraction of the radiation is absorbed by the preform material and, from the molecular agitation caused by this absorption, there is a release of heat
Implementation Method 2
Infrared heating of preforms using infrared lamps is very widespread because its implementation is relatively simple and well-controlled
Implementation Method 3
For PET containers, this technique offers higher yields than infrared heating, primarily due to PET's greater permeability to microwaves
Implementation Method 4
Another heating technique, currently known only at the prototype stage, involves subjecting the preform to microwave radiation
Data Source
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AI summary
Process for heating a container parison (3) made of plastic that extends along a main axis, this process comprising: a preheating phase in which the parison (3) is subjected to electromagnetic radiation in the infrared domain and at a power and/or wavelength that varies along the principal axis of the parison (3) and/or around this axis, so that, at the end of the preheating phase, the preform (3) has at least one what is called cold zone heated to a temperature T1 and at least one what is called hot zone heated to a temperature T2 strictly above T1; and a heating phase in which the parison (3) is then subjected to electromagnetic radiation in the microwave domain.