Gradual Ignition Emitters for Preform Thermal Conditioning
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Solution Overview
Problem
Conventional furnaces using halogen lamps for thermal conditioning of plastic preforms suffer from quality defects during startup and shutdown, with the first and last preforms often being superheated, leading to poor-quality containers.
Innovation Solution
A method and apparatus utilizing monochromatic electromagnetic-radiation sources, such as VCSEL diodes, that gradually ignite or extinguish emitters based on the position of the head or tail preforms within the furnace, ensuring a consistent thermal profile and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If all emitters are ignited simultaneously before production starts, then the furnace reaches appropriate temperature quickly, but the head preform receives excessive heat and becomes superheated causing quality defects
Solution Approach 1:
The patent divides the heating system into multiple independently controllable emitter zones along the preform transport path. Each emitter can be individually ignited or extinguished based on the position of preforms, allowing selective heating of different spatial regions. This segmentation enables the furnace to heat only the specific zone where a preform is located, preventing both superheating of the head preform and overheating of the tail preform while maintaining appropriate temperature for intermediate preforms.
2Temperature
If conventional halogen lamps are used for heating, then the furnace can be preheated, but the process is slow and requires delicate adjustments
Solution Approach 1:
The patent implements a control system that determines the position of head and tail preforms and activates emitters in advance of their arrival. By using sensors to detect preform positions and calculating their future locations based on transport speed, the system prepares the thermal field before preforms enter the heating zone. This preliminary action eliminates the need for slow conventional preheating while maintaining precise thermal control.
3Manufacturing precision
If emitters are gradually ignited for head preform, then thermal profile uniformity is improved, but the control system complexity increases
Solution Approach 1:
The patent employs a feedback control system that continuously monitors preform positions using sensors (such as coders or detection cells) and adjusts emitter activation accordingly. The control system receives position information, determines which emitters should be active based on calculated preform locations, and sends activation signals to individual emitters. This closed-loop feedback mechanism automates the complex coordination required for gradual emitter ignition, making the system manageable while maintaining precise thermal profile control.
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 approach ensures that all preforms receive a uniform thermal treatment, reducing scrap rates and enabling immediate production startup without preheating, while optimizing energy use by adjusting power delivery to emitters dynamically.
Implementation Method 1
emitters equipped with monochromatic electromagnetic-radiation sources (in particular lasers), whose emission spectrum essentially extends into the infrared range
Implementation Method 2
emitters that each comprise a number of monochromatic electromagnetic-radiation sources... in which the sources emit radiation into the cavity
Data Source
AI summary
Method for thermal conditioning, within a thermal conditioning unit that is equipped with a row of adjacent emitters that each comprise a number of monochromatic electromagnetic-radiation sources, of a queue of preforms of containers having a head preform or a tail preform, with this method comprising the following operations: Periodically determining the position of the head preform, or, respectively, of the tail preform; As the queue of preforms moves along, gradually igniting the emitters that are located downstream and in the vicinity of the head preform or, respectively, gradually extinguishing the emitters that are located upstream and in the vicinity of the tail preform.