Sterilizing Preform Condensation and Activation
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Solution Overview
Problem
Existing installations for sterilizing plastic preforms require high flow rates and pressures of sterilizing products, leading to inefficient consumption, residual droplets causing chemical attacks and 'orange peel' defects on bottles, and incomplete sterilization due to turbulent flow and uneven deposition.
Innovation Solution
A sterilization process involving projecting a jet of steam sterilizing product onto preforms at a temperature below condensation, followed by heating to activate and evaporate the product uniformly, ensuring complete sterilization without residual defects, using a laminar flow and radiant heating to maintain sterility and prevent 'orange peel' appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high flow rate and pressure of sterilizing product are used, then complete coverage of internal walls is achieved, but sterilizing product consumption increases and cost increases
Solution Approach 1:
The patent utilizes phase transition of the sterilizing product from liquid to vapor state. The sterilizing product is vaporized and introduced into the preform, where it condenses on the internal walls as a fine mist, ensuring complete coverage without requiring high flow rates or pressures. This phase transition mechanism allows effective sterilization with reduced consumable usage.
2Reliability
If high flow rate of sterilizing product is used, then sterilization coverage is improved, but residual droplets are deposited on internal walls causing 'orange peel' defects
Solution Approach 1:
The sterilizing product is applied in vapor phase which condenses on the preform walls, and then the preform is heated to evaporate any residual condensed liquid. This two-phase transition approach (vaporization followed by condensation, then re-evaporation) ensures complete sterilization coverage while eliminating residual droplets that would cause surface defects.
Solution Approach 2:
The process employs periodic action through sequential steps: first condensing the sterilizing vapor on the preform walls, then heating to evaporate residuals. This time-separated sequence of wetting and drying phases ensures thorough sterilization without leaving harmful residues on the surface.
3Quantity of substance
If turbulent flow is used to spray sterilizing product, then sterilizing product is distributed, but homogeneous deposition is not achieved and non-sterilized zones remain
Solution Approach 1:
The patent replaces the mechanical spray system (which creates turbulent flow and uneven deposition) with a thermal field-based system. The sterilizing product is introduced as vapor and distributed throughout the preform interior through thermal convection and diffusion, then condenses uniformly on all internal surfaces including hard-to-reach areas, ensuring homogeneous deposition without mechanical turbulence.
4Power
If high pressure compressed air is used to compress sterilizing product, then sterilizing product projection is enhanced, but droplet formation increases causing chemical attack on preform material
Solution Approach 1:
The patent changes the physical state parameter of the sterilizing product from liquid to vapor. By introducing the sterilizing product in vapor form rather than liquid, the need for high-pressure compression is eliminated. The vapor naturally distributes throughout the preform interior and condenses on surfaces, providing adequate projection power without creating damaging droplets that would cause chemical attack on the preform material.
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 process reduces sterilizing product consumption, eliminates 'orange peel' defects, and ensures thorough sterilization of preforms, achieving a high degree of sterility with reduced operational costs and improved product quality.
Implementation Method 1
vaporized on each preform whose temperature is lower than the condensation temperature of the sterilizing product so that a film of fog of sterilizing product, substantially uniform, is deposited by condensation
Implementation Method 2
heating the preform thus treated by radiation to bring it to a temperature greater than or equal to the activation temperature of the sterilizing product
Implementation Method 3
bring it to a temperature greater than or equal to the temperature activation so as to sterilize at least the internal wall of the preform... higher than the activation temperature and the evaporation temperature to eliminate the sterilizing product by evaporation
Implementation Method 4
projecting a flow of sterilizing product in the form of a jet of steam towards the preform so as to cause the deposition by condensation of a film of mist of substantially uniform sterilizing product
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a sterilization method and to an installation (10) for producing sterile bottles (14) by blow molding sterilized preforms (12) according to the method, characterized in that, at the spraying station (28), the flow (F) of sterilizing product is atomized onto each preform (12) whose temperature (T1) is less than the condensing temperature (Tc) of the sterilizing product so that a film of mist of the sterilizing product deposits by condensation at least onto the inner wall to be sterilized, and is characterized in that, at the activation station (50) of the sterilizing product of the sterilizing unit (26), each preform (12) treated in the aforementioned manner is heated by radiation to a temperature (T2) greater than or equal to the activation temperature (Ta) in order to sterilize at least the inner wall of the preform (12).