Heating Device Reflector Curvature for Preform Base Body
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Solution Overview
Problem
Existing heating devices for plastic preforms, particularly those using infrared radiation, fail to effectively separate the base body and mouthpiece areas, leading to undesired heating of the mouthpiece during the blow molding process, which can result in deformation and require complex and energetically unfavorable cooling methods.
Innovation Solution
A heating device with a reflector system featuring a combination of parabolic and elliptical sections, where the first section directs radiation directly to the base body and the second section reflects radiation to prevent heating of the mouthpiece, allowing for concentrated heating below the support ring without heating the mouthpiece area, utilizing a specially designed parabolic profile and reflective surfaces to optimize radiation distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional infrared radiators with reflectors are used to heat plastic preforms, then the base body can be heated, but the mouth area is also unnecessarily heated causing deformation and requiring complex cooling
Solution Approach 1:
The reflector device is divided into multiple sections (first section, second section, third section) with different curvature profiles. Each section is responsible for directing radiation to specific areas of the preform, thereby segmenting the heating zones and preventing unwanted heating of the mouth area while maintaining effective heating of the base body.
Solution Approach 2:
Different sections of the reflector device have different local geometric properties (parabolic, hyperbolic, or elliptical curvatures) optimized for specific heating zones. The first section targets the base body, the second section prevents mouth heating through its specific curvature, and the third section provides additional focused heating where needed, creating locally optimized heating quality throughout the preform.
2Productivity
If parabolic reflectors are used to focus radiation, then heating efficiency is improved, but the reflectors must be very wide and focus less precisely
Solution Approach 1:
The reflector device combines multiple reflector types (parabolic, hyperbolic, and elliptical sections) into a single integrated structure. This merging of different geometric forms allows the system to achieve both the wide coverage needed for efficient heating and the precise focusing capability required to concentrate radiation accurately on the base body without unnecessary mouth heating.
Solution Approach 2:
The reflector device employs varied curvature profiles across different sections - parabolic curvature in the first section for broad coverage, hyperbolic curvature in the second section for precise focusing, and elliptical curvature in the third section for targeted concentration. This strategic use of different curvatures resolves the contradiction between wide coverage and precise focusing.
3Manufacturing precision
If elliptical reflectors are used to bundle radiation, then focusing is improved, but the radiation is fanned out again in the second preform wall heating the muzzle
Solution Approach 1:
The reflector device segments the radiation path into distinct zones using different reflector sections. The first section handles base body heating, the second section with its specific hyperbolic or elliptical curvature controls radiation that might otherwise reach the mouth, and the third section provides additional targeted heating. This segmentation prevents the radiation fan-out effect that heats the muzzle.
Solution Approach 2:
The reflector device changes the geometric parameters (curvature type and magnitude) across different sections to control radiation behavior. By transitioning from parabolic to hyperbolic or elliptical curvature in subsequent sections, the system dynamically adjusts the radiation distribution parameters to achieve precise focusing where needed while preventing over-heating in other areas.
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 solution enables precise and controlled temperature control of plastic preforms, minimizing the risk of mouthpiece deformation and improving energy efficiency by directing almost all radiation to the base body, thus enhancing the blow molding process.
Implementation Method 1
a first radiation source (42) which emits thermal radiation
Implementation Method 2
infrared radiators with reflectors located behind them
Implementation Method 3
at least one reflector device (50) which reflects at least a portion of the thermal radiation emitted by the radiation source (42) in the direction of the plastic preforms (10)
Data Source
Figure 1~2b
Figure 3~4b
Figure 5~6a
AI summary
A device (1) for heating plastic preforms (10), comprising a transport device (2) which transports the plastic preforms (10) along a predetermined transport path (T), and at least one heating device (4) which is arranged stationary with respect to the transport path of the plastic preforms (10), wherein the heating device (4) has at least one first radiation source (42) which emits thermal radiation and at least one reflector device (50) which reflects at least a portion of the thermal radiation emitted by the radiation source (50) in the direction of the plastic preforms (10). According to the invention, the reflector device (50) has a first section (52) with a substantially parabolic curvature, and a second section (54, 56) with a curved profile, the curvature of which differs from that of the first section (52).