Sterilisation Gas Flow Control in Aseptic Packaging

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Solution Overview

Problem

In filling machines, the uncontrolled return flow of sterilization gas during the gas sterilization stage leads to unintended spreading in the aseptic chamber, compromising the aseptic air flow barrier and reducing the efficiency of gas reuse, while also posing a risk of re-infection to the package surface.

Innovation Solution

A method and apparatus that direct the gas flow into the package via obliquely inclined supply channels, creating a helical flow along the inner periphery, catching the return flow in a central channel and redirecting it vertically along the outer surface, ensuring controlled gas circulation and reuse, while minimizing recontamination risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sterilisation gas is supplied centrally to the package, then the inside of the package is sterilised, but the gas spreads uncontrolled in the surrounding chamber and compromises the aseptic air flow barrier

Engineering Contradiction:
Improvesterilisation effectivenessVSAvoiduncontrolled gas spread
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The gas supply is segmented into multiple nozzles arranged circumferentially around the package opening, with each nozzle directed at a specific zone. This segmentation allows controlled distribution of sterilisation gas along the package surface and prevents uncontrolled spreading in the chamber, maintaining the aseptic air flow barrier while ensuring thorough sterilisation coverage.

Inventive Principle:
Principle #1Segmentation

2Reliability

If gas flow is increased to ensure sterilisation coverage, then sterilisation effectiveness improves, but gas reuse efficiency decreases and recontamination risk increases

Engineering Contradiction:
Improvesterilisation effectivenessVSAvoidgas reuse efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Each gas nozzle is positioned and directed to target specific local zones on the package surface. The gas flow rate and direction are optimised for each local area, ensuring adequate sterilisation coverage without excessive overall gas consumption. This localised approach maintains sterilisation effectiveness while reducing total gas usage and improving reuse efficiency.

Inventive Principle:
Principle #3Local quality

3Reliability

If gas flow is directed to sterilise the outside of the package, then recontamination risk is reduced, but gas flow control complexity increases

Engineering Contradiction:
Improverecontamination preventionVSAvoidgas flow control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The gas nozzles are arranged in a circumferential pattern around the package opening, utilizing the radial dimension to achieve comprehensive outside surface coverage. This spatial arrangement naturally directs gas flow along the package exterior without requiring complex individual nozzle control mechanisms, simplifying the overall system while effectively preventing recontamination.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 reduces the gas mass flow, preventing recontamination, enhancing gas reuse, and maintaining the aseptic air flow barrier, thereby improving the sterilization process efficiency and economy.

Implementation Method 1

supply channels being obliquely inclined giving rise to a helical gas mass flow along the inner periphery of the package

Methodology Applied
Scientific EffectHelical flow: Vortex Ring

Implementation Method 2

a heating zone for a heating of the material in the packages to about 70°C

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

The sterilisation agent is intended to remain in gas form throughout the entire sterilisation stage

Methodology Applied
Scientific EffectPhase stability: Phase Change

Data Source

PatentEP1934098B1A method and an apparatus for sterilising packages
Publication Date: 2011.12.14 TETRA LAVAL HOLDINGS & FINANCE SA
  • EP1934098B1 patent drawingFigure 1
  • EP1934098B1 patent drawingFigure 2~3
  • EP1934098B1 patent drawingFigure 4

AI summary

The invention relates to a method of supplying gas or gas mixture to the inside of partly formed packages in a filling machine before a subsequent filling and sealing of the packages. It comprises supplying said gas or gas mixture as at least one flow into the package (1) via an opening in the package (1), the supply being made such that the at least one flow is flowing into the package (1) to the inner region of the package and is thereafter returning back through the opening, and temporarily catching the return flow from the package (1) in a delimited space outside the opening, and directing the return flow out from the space in such a way that a substantially vertical flow along the outer envelope surface of the package (1) is formed. The invention also relates to an apparatus.