Hydrogen Peroxide Sterilization Gas Circulation

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Solution Overview

Problem

Existing methods for sterilizing complex loads with hydrogen peroxide vapor often result in uneven distribution and excessive concentration at the edges, leading to prolonged processing times and residual toxic substances due to absorption issues.

Innovation Solution

A method involving sub-atmospheric pressure creation, introduction of vaporized hydrogen peroxide, and enhanced gas circulation within the sterilization chamber, controlled by a gas circulation device, ensures uniform distribution and efficient outgassing using steam cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If vaporized hydrogen peroxide is introduced into an evacuated sterilization chamber with a hold period, then sterilization is achieved, but a gradient of hydrogen peroxide concentration is formed with excessively high concentration at the periphery and insufficient concentration at the center

Engineering Contradiction:
Improveuniformity of sterilant distributionVSAvoidsterilization effectiveness
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies dynamic gas circulation during the sterilization process, transitioning from a static hold period to an active circulation phase. The gas circulation device is activated to move hydrogen peroxide vapor throughout the chamber, ensuring uniform distribution to all areas of the load including the center, while preventing excessive accumulation at the periphery. This dynamic approach resolves the concentration gradient problem by continuously redistributing the sterilant.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes gas circulation devices (pneumatic systems) to actively move hydrogen peroxide vapor through the sterilization chamber. By introducing controlled gas flows that circulate the vapor, the system achieves uniform distribution of the sterilant throughout the chamber and load, eliminating the concentration gradients that occur with static methods.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If excessive concentration of sterilant is used to ensure proper sterilization, then sterilization effectiveness is improved, but excessive absorption of sterilant into the material occurs leading to residual toxic substances and prolonged processing periods

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent employs feedback control through monitoring devices that detect hydrogen peroxide concentration and absorption levels in real-time. When the predetermined absorption level is reached, the system automatically terminates the sterilization cycle, preventing excessive absorption. This feedback mechanism ensures adequate sterilization while avoiding prolonged exposure that would lead to excessive absorption and extended processing times.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the concentration and exposure parameters of hydrogen peroxide during the sterilization process. By controlling the gas circulation rate and monitoring absorption levels, the system maintains optimal sterilization effectiveness while preventing excessive concentration buildup that would cause prolonged processing times and residual toxic substances.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If hydrogen peroxide sterilization is performed on loads with complex structure and absorbing characteristics, then sterilization coverage is improved, but uneven absorption occurs with high concentration at edges and low concentration at center

Engineering Contradiction:
Improvesterilization uniformityVSAvoidload structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses gas circulation devices to create controlled airflow patterns that penetrate complex load structures. The circulating gas carries hydrogen peroxide vapor into difficult-to-reach areas including the centers of complex loads, ensuring uniform distribution regardless of load structural complexity. This pneumatic approach overcomes the limitations of passive diffusion in complex geometries.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent applies dynamic gas circulation to adapt to complex load structures. The circulation system can adjust flow patterns and velocities to ensure penetration into complex geometries, maintaining uniform sterilant distribution throughout the load regardless of its structural complexity.

Inventive Principle:
Principle #15Dynamics

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 ensures reliable and repeatable sterilization with reduced sterilant usage, minimizing residual toxic substances and shortening processing times by maintaining consistent hydrogen peroxide concentration throughout the load.

Implementation Method 1

the resulting sterilizing atmosphere is circulated within the chamber at a flow rate determined by the prevailing pressure using a gas circulation device internal to the chamber

Methodology Applied
Scientific EffectGas circulation: Convection

Implementation Method 2

the chamber is evacuated to a minimum pressure determined by the characteristics of the load

Methodology Applied
Scientific EffectVacuum evacuation: Vacuum

Implementation Method 3

an atmosphere of vaporized hydrogen peroxide is introduced in an amount determined by the desired final concentration throughout the load

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 4

efficient outgassing using steam cycles

Methodology Applied
Scientific EffectSteam heating: Heating

Data Source

PatentEP3056223B1Method and device for hydrogen peroxide sterilization
Publication Date: 2020.11.04 STERIS EURO INC SUOMEN SIVULIIKE
  • EP3056223B1 patent drawingFigure 1

AI summary

The invention relates to the sterilization of a load of goods with hydrogen peroxide vapor in a closed space. The method involves a sequence of creating a sub-atmosphelic pressure in a sterilization chamber, introduction of vaporized hydrogen peroxide and the use of a gas circulation device within the sterilization chamber, whereby the output of the gas circulation device is controlled according to the pressure in the sterilization chamber. A uniform and consistent distribution of hydrogen peroxide throughout the load is achieved.