CO2 Snow Cooling for Plastic Container Stability
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Solution Overview
Problem
Existing container treatment systems face challenges in efficiently cooling plastic containers below the glass transition temperature without incurring high production and operating costs, while also ensuring label adhesion and hygiene, as conventional methods require drying and can lead to contamination risks.
Innovation Solution
A container treatment system utilizing a cooling device with an applicator for carbon dioxide snow, which rapidly cools plastic containers to -50°C, providing stable cooling without dripping and contamination risks, and can be integrated into the blow molding machine or used downstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional air cooling or contact cooling in blow molds is used, then plastic containers can be cooled below glass transition temperature, but production and operating costs increase
Solution Approach 1:
The patent employs carbon dioxide snow, which is CO2 in a solid state that sublimates directly to gas. This phase transition provides intense cooling effect as the CO2 absorbs heat during sublimation, rapidly cooling the container walls below glass transition temperature without requiring expensive conventional cooling systems
Solution Approach 2:
The invention replaces complex mechanical cooling systems (contact cooling in blow molds or extensive air cooling systems) with a simpler CO2 snow application system. The CO2 snow is delivered via nozzles that can be integrated into the blow mold or applied downstream, eliminating the need for elaborate cooling infrastructure
2Temperature
If water spray cooling is used, then plastic containers can be cooled efficiently, but labels will not adhere sufficiently due to moisture
Solution Approach 1:
The CO2 snow undergoes direct sublimation from solid to gas state upon contact with the container surface. This phase transition ensures that no liquid water or moisture remains on the container surface, allowing labels to adhere properly while still achieving efficient cooling through the sublimation process
Solution Approach 2:
The CO2 snow acts as an intermediary cooling medium that transfers heat away from the container without leaving residual moisture. Unlike water spray which leaves liquid residue, the CO2 sublimates completely, providing a clean cooling effect that is compatible with subsequent labeling operations
3Temperature
If open water supply cooling is used, then plastic containers can be cooled, but hygiene concerns arise due to contamination risks
Solution Approach 1:
Carbon dioxide is an inert gas that does not support microbial growth or chemical reactions. Using CO2 snow as the cooling medium creates an inert environment that eliminates hygiene concerns associated with open water supplies, as CO2 cannot contaminate the container or support bacterial growth
Solution Approach 2:
The CO2 snow is applied as a transient cooling medium that sublimates completely and disappears after use. This disposable nature of the CO2 snow eliminates contamination risks, as there is no residual liquid or open water system that could harbor pathogens or require hygiene maintenance
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 system achieves stable cooling of plastic containers, preventing deformation and ensuring effective label adhesion, while reducing production costs and minimizing contamination risks due to the direct gaseous state of carbon dioxide snow.
Implementation Method 1
the snow crystals of the carbon dioxide snow go directly from the solid to the gaseous state
Implementation Method 2
the cooling device for cooling the plastic containers includes at least one applicator for carbon dioxide snow, the plastic containers are cooled by means of the carbon dioxide snow
Data Source
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AI summary
Container treatment plant (1) for the production of plastic containers (7), comprising a blow molding machine (2) designed to heat preforms (8) and to transform them into the plastic containers (7) in blow molds (2d), a conveyor (3) to transport the plastic containers (7) at least after forming, and a cooling device (4) arranged on the conveyor (3) to cool the plastic containers (7) after forming, characterized in that the cooling device (4) for cooling the plastic containers (7) comprises at least one applicator (4a) for carbon dioxide snow.