Helical Preform Cooling Tunnel for Fast Uniform PET Cooling
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Solution Overview
Problem
Current production plants for thermoplastic containers, particularly PET, face challenges in reducing preform cooling times to enhance productivity and prevent deformation, as existing cooling systems are inefficient and may cause crystalline zones, leading to increased production times and potential manufacturing faults.
Innovation Solution
A high-speed cooling apparatus with a helical guide and cooling tunnel system that uses a chain or cable with clips to grasp preforms and a double-walled cylindrical casing for efficient air flow, allowing countercurrent and concurrent air paths to achieve uniform and rapid cooling, reducing cooling times and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the preforms are cooled rapidly to ambient temperature, then the productivity increases and the preform transfer speed increases, but the preforms may form crystalline zones and deform due to uneven cooling
Solution Approach 1:
The invention transitions from conventional linear or radial cooling paths to a helical cooling path in three-dimensional space. The guide defines a closed helical path that wraps around a central axis, allowing preforms to follow a spiral trajectory during cooling. This dimensional transformation increases the effective cooling path length and surface area exposure without increasing the footprint, enabling more uniform heat dissipation while maintaining high transfer speeds.
Solution Approach 2:
The helical guide and cooling tunnel employ curved geometries instead of straight lines. The preforms traverse a curved helical path within the cooling tunnel, ensuring continuous contact with cooling surfaces and exposure to cooling air from multiple angles. This curvature enables uniform cooling across the preform surface while preventing localized hot spots that would cause crystallization or deformation.
2Manufacturing precision
If the preforms are cooled slowly to ambient temperature, then the preform uniformity is maintained, but the productivity decreases and the production time increases
Solution Approach 1:
The helical cooling system enables continuous cooling action throughout the entire preform surface area. As preforms move along the helical path, they are constantly exposed to cooling air and contact cooling surfaces, eliminating idle cooling periods. The closed-loop helical guide ensures that cooling action is maintained continuously from entry to exit, achieving both rapid heat removal and uniform temperature distribution.
Solution Approach 2:
The cooling process begins immediately after preform formation, with preforms entering the cooling tunnel at controlled temperatures. The helical guide pre-positions preforms along the cooling path, ensuring optimal exposure to cooling surfaces from the start. This preliminary arrangement of preforms in the helical configuration maximizes cooling efficiency from the initial moment, preventing overheating and crystallization before they can occur.
3Device complexity
If conventional cooling systems are used, then the device complexity is low, but the preform cooling time is excessive and deformation occurs
Solution Approach 1:
The invention introduces a helical three-dimensional cooling path instead of conventional linear or planar cooling arrangements. The guide defines a closed helical stretch that develops about a vertical middle axis, creating a spiral cooling trajectory. This dimensional transformation increases the cooling path length and surface area exposure without proportionally increasing device complexity, as the helical structure is formed by a single continuous guide and cooling tunnel.
Solution Approach 2:
The guide and cooling tunnel are merged into an integrated structure where the guide defines both the mechanical path for preform transport and the thermal path for cooling. The cooling tunnel encompasses the helical guide, combining the functions of structural support, preform guidance, and thermal management into a single unified system. This merging reduces the number of separate components while achieving superior cooling performance.
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
The cooling apparatus significantly reduces preform cooling times, enhances productivity, and prevents deformation by ensuring uniform cooling, making it suitable for high-speed production of various preform sizes and weights, while maintaining energy efficiency and flexibility.
Implementation Method 1
a double-walled cylindrical casing for efficient air flow, ensuring rapid and uniform cooling by countercurrent and concurrent air paths within the tunnel
Data Source
AI summary
The invention relates to an apparatus for cooling a plurality of preforms made of thermoplastic material which continuously move on a conveyor belt. The apparatus includes a cylindrical casing with a vertical extension formed by two coaxial cylinders, such a casing contains a guide crossed by a chain or a cable for transporting the preforms therein. The guide, which forms a closed path, comprises a first helical stretch, which raises from the lower plane starting from a station in which the preforms coming from a conveying device are hooked by the chain or by the cable, a second straight stretch, which returns the preforms to the lower plane once they have reached the upper plane, and a third flat stretch at the height of the lower plane, which returns the preforms to the arrival station. The helical stretch of the guide is contained within a cooling tunnel formed in the gap between the two walls of the outer cylinder and the inner cylinder of said casing. The cooling air is conveyed within the cooling tunnel by a specific manifold which is located within the casing.