Gas Sterilization Challenge Device With Restricted Flow Paths

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Solution Overview

Problem

Existing sterilization process verification methods are not accurate and cost-effective, particularly for gas sterilization processes.

Innovation Solution

A sterilization challenge device comprising an outer and inner container with specific dimensions and flow paths, using polymeric and metallic materials, and a cap with sealing members to create a fluid-tight closure and controlled gas flow, ensuring the chemical indicator changes color only when the sterilization process is complete.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If gas sterilization process verification is performed using conventional methods, then the sterilization process can be completed, but the verification accuracy is insufficient and cost-effective is poor

Engineering Contradiction:

Improveverification accuracyVSAvoidcost-effectiveness

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The challenge device is divided into multiple functional components: an outer container with restricted flow path, an inner container holding the chemical indicator, and a cap with sealing member. This segmentation allows each component to be optimized for its specific function while maintaining overall cost-effectiveness and verification accuracy

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A chemical indicator serves as an intermediary substance that mediates between the gaseous sterilant and the verification system. The indicator undergoes a detectable change (color change or fluorescence) only when exposed to the sterilant through the restricted flow path, providing accurate verification without requiring complex measurement equipment

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the chemical indicator is exposed to gaseous sterilant freely, then the indicator can change color, but the verification accuracy cannot ensure completion of sterilization cycle

Engineering Contradiction:

Improvesterilization completion verificationVSAvoidflow path restriction structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The flow path restriction is applied locally at specific positions (outer container walls and/or cap) rather than uniformly throughout the entire device. This localized restriction creates a controlled flow path that allows the indicator to change color only after the sterilization cycle is complete, providing accurate verification without excessive structural complexity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The restricted flow path is pre-configured in the device structure before sterilization begins. This preliminary action ensures that the gaseous sterilant must traverse a controlled path to reach the indicator, guaranteeing that color change occurs only after complete exposure throughout the sterilization cycle

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the inner container open end is not sealed, then assembly is simple, but the chemical indicator cannot be protected from premature exposure to sterilant

Engineering Contradiction:

Improveindicator protectionVSAvoidassembly simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The sealing member is designed to be self-activating upon assembly. When the cap is screwed onto the outer container, the sealing member automatically engages with the inner container open end, creating a fluid-tight seal without requiring additional operations. This self-service approach maintains assembly simplicity while ensuring reliable indicator protection

Inventive Principle:

Principle #25Self-service

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 device provides precise verification of gas sterilization efficacy by restricting gas flow to ensure the chemical indicator changes color only upon completion of the sterilization cycle, enhancing accuracy and reducing costs.

Implementation Method 1

the cap may be provided with a sealing member, wherein the sterilization challenge device may be configured such that the inner container open end is covered by the sealing member and pressed against the sealing member

Methodology Applied

Scientific EffectSealing:

Implementation Method 2

ensuring the chemical indicator changes color only when the sterilization process is complete

Methodology Applied

Scientific EffectColor change reaction:

Implementation Method 3

at least one hole defined through a wall of the container to provide a flow path for a gaseous sterilant into the chamber

Methodology Applied

Scientific EffectRestricted flow:

Data Source

PatentEP4392084B1Gas sterilization process challenge device

Publication Date: 2025.10.01 AMERICAN STERILIZER CO

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AI summary

A sterilization challenge device for verifying the efficacy of a gas sterilization process includes an outer container, an inner container, a chemical indicator, and a cap. The outer container includes an open end, a closed end, a chamber configured to contain the inner container containing the chemical indicator, and at least one hole arranged proximate the open end. The cap is configured to engage with the outer container to close the open end, and the at least one hole is configured to provide a flow path for the gaseous sterilant into the chamber.