Preform Rotation System for Oval Container Wall Thickness
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Solution Overview
Problem
Existing ovens for preforms struggle to achieve uniform wall thickness in containers with oval cross-sections, as uniform heating leads to varying thicknesses in different areas of the bottle.
Innovation Solution
An oven design that allows for differentiated heating of preform sections by rotating the preforms 180°, ensuring longer heating for sections corresponding to the long sides of the oval container and less heating for sections corresponding to the short sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform heating is applied to the preform body, then the heating process is simple and energy-efficient, but the resulting container has non-uniform wall thickness with thicker walls at the long side and thinner walls at the short sides of the oval cross-section
Solution Approach 1:
The patent applies differentiated heating zones along the preform path, with longer exposure time and higher temperature for sections corresponding to the long sides of the oval container, and shorter exposure time for sections corresponding to the short sides. This local quality variation in heating parameters compensates for the geometric differences and achieves uniform wall thickness throughout the container.
2Manufacturing precision
If differentiated heating is applied to achieve uniform wall thickness in oval containers, then manufacturing precision is improved, but the heating system becomes complex and costly
Solution Approach 1:
The patent employs a rotating preform mechanism that dynamically changes the orientation of the preform relative to the heating zones during the heating process. This dynamic rotation allows a single heating system to achieve differentiated heating patterns by controlling the rotation timing and speed, rather than requiring multiple fixed heating zones for each section of the preform.
3Manufacturing precision
If the preform is rotated 180° for differentiated heating, then wall thickness uniformity is achieved, but the heating time and energy consumption increase
Solution Approach 1:
The patent implements periodic rotation of the preform at specific intervals during the heating process. The preform is rotated 180° at predetermined positions along the heating path, creating periodic heating cycles that ensure uniform heat distribution. This periodic action allows efficient energy utilization by concentrating heating energy on specific sections at specific times, rather than continuously heating the entire preform uniformly.
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 enables the production of containers with oval cross-sections and substantially uniform wall thickness, achieved in a simple and cost-effective manner.
Implementation Method 1
The preforms are softened in special ovens which comprise a series of heating modules, typically infrared modules
Data Source
AI summary
An oven for preforms and in particular a preform rotation system heats portions of the preform in a preferential manner. An oven (1) for blowing or stretch-blowing preforms (P) to provide containers (C) with oval section includes a path (2) for the preforms (P), transfer system (3) of the preforms (P) from a transport system upstream of the oven (1) and a transfer system (4) of the heated preforms (P) from the oven (1) to a downstream transport. Mandrels (9) are slidingly carried along the path (2), the mandrels temporarily engage with the preforms (P) to conduct the preforms along the path (2). The oven (1) includes at least one first heating module (10) and at least one second heating module (10′). The oven (1) includes elements (22, 25) for rotating the preforms (P) by 180°, the elements being in median position of the second heating module (10′).