Thermally Switching Valve for Sterilization Indicator Accuracy

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Solution Overview

Problem

Existing devices for detecting successful thermal disinfection or sterilization of hollow body objects often produce false-positive results due to chemical indicators coming into contact with process media other than steam, leading to incorrect sterilization validation.

Innovation Solution

A device with a thermally switching valve that selectively connects or disconnects the process media line from the indicator receptacle, ensuring only the sterilization medium interacts with the indicator, preventing false positives by maintaining the valve closed during non-sterilization processes and opening it only when a sterilization medium flows through.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a chemical indicator is placed in a test body with a steam inlet hole to detect sterilization success, then the indicator can detect steam sterilization, but process media other than steam (including water) can also enter the indicator holder and cause false-positive color changes

Engineering Contradiction:
Improveaccuracy of sterilization detectionVSAvoidcompatibility with multiple process media
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

A thermally switching valve is introduced as an intermediary component between the process media line and the indicator holder. This valve selectively controls which media can reach the chemical indicator, allowing steam to pass through while blocking other process media. The valve acts as a gatekeeper that mediates the interaction between process media and the indicator, preventing false positives while maintaining accurate sterilization detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The indicator holder is designed with a specialized opening configuration where the opening is positioned to face upward and has dimensions specifically suited for steam ingress. This local structural quality ensures that steam can enter the indicator holder through the upward-facing opening during sterilization, while other process media flowing through the main line do not gain access to the indicator.

Inventive Principle:
Principle #3Local quality

2Reliability

If complex flow guides, porous materials or membranes are used to prevent contact between process media and the indicator, then false positives are reduced, but the sterilization medium takes longer to reach the indicator

Engineering Contradiction:
Improveaccuracy of sterilization detectionVSAvoidsterilization detection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The thermally switching valve serves as a temporal intermediary that opens only at the appropriate moment in the sterilization process. Rather than using continuous barriers like membranes or porous materials that delay steam access, the valve remains closed during other process media flow and opens specifically when sterilization conditions are present, allowing immediate indicator response without time loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from static barriers (membranes, porous materials) that continuously impede flow to a dynamic thermally switching valve that adapts its state based on temperature conditions. The valve opens dynamically when exposed to sterilization temperatures, allowing steam to reach the indicator immediately without the time delay imposed by diffusion through porous materials or complex flow paths.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a thermally switching valve is used to selectively connect the process media line to the indicator receptacle, then false positives are reduced, but the device complexity increases

Engineering Contradiction:
Improveaccuracy of sterilization detectionVSAvoidstructure of detection device
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thermally switching valve is designed to operate autonomously based on temperature conditions without requiring external control systems, sensors, or power sources. The valve material itself responds to the thermal environment, opening when sterilization temperatures are present and closing when they are not. This self-service mechanism adds minimal complexity while achieving reliable false positive prevention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The valve's operational state changes in direct response to temperature parameter changes in the process media. As the media temperature reaches sterilization levels, the valve automatically transitions from closed to open state, and reverses when cooling occurs. This parameter-driven operation simplifies control architecture compared to electronic control systems while maintaining high reliability.

Inventive Principle:
Principle #35Parameter changes

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 configuration significantly reduces false-positive results by ensuring the indicator only reacts to the sterilization medium, providing accurate validation of the disinfection or sterilization process.

Implementation Method 1

a thermally switching valve (16), through which a flow connection between the process media line (11) and the indicator receptacle (14) can be established or interrupted

Methodology Applied
Scientific EffectThermal switching: Phase Change

Data Source

PatentEP3485915B1Device and method for detecting a successful thermal disinfection or sterilization
Publication Date: 2022.04.20 MELAG MEDIZINTECHN GMBH & CO KG
  • EP3485915B1 patent drawingFigure 1
  • EP3485915B1 patent drawingFigure 2

AI summary

The invention relates to a device for verifying successful thermal disinfection or sterilization, comprising a process media line (11) and an indicator receptacle (14) fluidically connected to the process media line (11) for receiving an indicator (17) that serves to indicate the success of thermal disinfection or sterilization. According to the invention, the device is characterized by having a valve (16) by means of which a flow connection between the process media line (11) and the indicator receptacle (14) can be established or interrupted. The invention further relates to a device for the thermal disinfection or sterilization of hollow objects using such a device, and to a method for the thermal disinfection or sterilization of hollow objects using such a device.