Vacuum Chamber Moisture Detection for Hydrogen Peroxide Sterilization

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Solution Overview

Problem

Current chemical vapor sterilization processes for medical devices are inefficient due to the time required to confirm sterilization efficacy, which can lead to inventory management issues and risk of infection, especially when moisture is present in the vacuum chamber, as it can interfere with hydrogen peroxide sterilization.

Innovation Solution

A sterilization system that uses a humidity sensor to measure moisture content within the vacuum chamber by withdrawing air, maintaining a conditioning pressure, and reintroducing air to detect residual water vapor, allowing for accurate determination of chamber dryness before introducing hydrogen peroxide, and incorporating load conditioning techniques to remove excess moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sterilization processes are used without moisture detection, then the sterilization can proceed without delay, but the sterilization efficacy cannot be confirmed and may be compromised by moisture presence

Engineering Contradiction:
Improvesterilization efficacyVSAvoidtime to confirm sterilization efficacy
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary moisture detection by drawing vacuum and measuring pressure changes before introducing the sterilant. This preliminary action confirms the absence of moisture that would compromise sterilization efficacy, allowing the process to proceed confidently without delay.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors pressure changes during vacuum drawing and provides feedback on moisture presence. This feedback mechanism enables real-time determination of whether sterilization conditions are appropriate, eliminating uncertainty and potential reprocessing delays.

Inventive Principle:
Principle #23Feedback

2Reliability

If moisture detection methods are implemented, then sterilization efficacy can be confirmed, but the system complexity increases

Engineering Contradiction:
Improvesterilization efficacy confirmationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses the existing vacuum pump and pressure sensor to perform moisture detection as a self-service function. The vacuum drawing process serves dual purposes: creating vacuum conditions for sterilization and simultaneously detecting moisture through pressure change measurement. This eliminates the need for separate moisture detection equipment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pressure sensor and vacuum system perform multiple functions: they create the vacuum environment required for sterilization and simultaneously detect moisture presence through pressure change analysis. This multi-functionality reduces overall system complexity while enabling reliable sterilization verification.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Quantity of substance

If vacuum drawing is performed to remove moisture, then moisture content decreases, but the process time increases

Engineering Contradiction:
Improvemoisture contentVSAvoidvacuum drawing time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The system performs partial vacuum drawing just sufficient to detect moisture presence through pressure changes, rather than extending vacuum drawing to completely remove all moisture. This partial action achieves the critical detection function without unnecessary time extension.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system rapidly draws vacuum only long enough to measure pressure changes and determine moisture content, then quickly transitions to the sterilization phase. This rushing through the vacuum drawing phase minimizes time loss while still achieving the essential moisture assessment.

Inventive Principle:
Principle #21Skipping (Rushing through)

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 time needed to confirm sterilization efficacy, ensures effective hydrogen peroxide sterilization by ensuring dry conditions, and prevents the use of non-sterile devices, thereby minimizing infection risks and optimizing inventory management.

Implementation Method 1

A first humidity sensor disposed within the vacuum chamber and configured to detect water vapor in a gas phase

Methodology Applied
Scientific EffectHumidity sensing: Hygrometer

Implementation Method 2

A vacuum pump configured to draw a vacuum within the vacuum chamber

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 3

If healthcare personnel erroneously introduced water into the chamber on the load, the water will begin evaporating as the pressure within the chamber is lowered

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

The chamber may be heated, which may help vaporize water that may be within the chamber

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 5

the hydrogen peroxide gas may be excited via an electric field to change the gas into a plasma

Methodology Applied
Scientific EffectPlasma: Plasma

Data Source

PatentEP3243531B1Apparatus and method for detecting moisture in a vacuum chamber
Publication Date: 2023.10.04 ASP GLOBAL MFG GMBH
  • EP3243531B1 patent drawingFigure 1
  • EP3243531B1 patent drawingFigure 2
  • EP3243531B1 patent drawingFigure 3

AI summary

A method of operating a sterilization system having a vacuum chamber for sterilizing instruments, the chamber connected to a reservoir of sterilant by a valve in a closed state, is disclosed. The method comprises placing the instruments in a non-sterile state in a sterilization pack, opening the chamber, placing the pack into the chamber, closing the chamber, withdrawing a first volume of air from the chamber, changing a volume of liquid water into vapor, opening the valve, introducing the sterilant into the chamber, withdrawing the sterilant from the chamber, introducing a second volume of air into the chamber, opening the chamber, removing the pack from the chamber, and removing the instruments in a sterile-state from the pack. The method may also include taking a baseline humidity measurement while the pressure within the chamber is a first pressure, lowering the pressure within the chamber to a conditioning pressure, maintaining the conditioning pressure for a dwell time, increasing the pressure within the chamber, acquiring a second humidity measurement from within the chamber, and comparing the baseline humidity measurement to the second humidity measurement.