Biological Indicator Shuttle System for Sterilization Testing
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Solution Overview
Problem
Existing Biological Indicator Evaluator Resistometers (BIER) systems experience significant errors in measuring the 'D' value due to transient periods during sterilization cycles, especially when using strong sterilants or weak biological indicators, where exposure times are short, leading to inaccuracies in determining the efficacy of sterilization methods.
Innovation Solution
A high-speed biological indicator shuttle system with a test chamber, loading chamber, and a movable valve element that rapidly exposes and removes biological indicators from a sterilant environment, minimizing transient exposure periods and allowing for precise control over sterilant vapor circulation and purging, enabling exposure times ranging from seconds to hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional BIER system is used with strong sterilants or weak biological indicators, then the sterilization testing can be performed, but significant errors occur in the 'D' value measurement due to transient exposure periods
Solution Approach 1:
The biological indicator is pre-loaded into the test chamber before the sterilization cycle begins. The system establishes the desired sterilant concentration in the test chamber beforehand, then immediately introduces the biological indicator to begin exposure at the correct concentration without any transient period. This preliminary preparation eliminates the ramp-up time that would otherwise cause measurement errors.
Solution Approach 2:
The system dynamically controls the introduction and removal of the biological indicator based on real-time monitoring of sterilant concentration. The movable valve element and indicator holder enable flexible timing of exposure start and end points, allowing the system to adapt to different sterilization protocols and minimize transient exposure periods while maintaining measurement accuracy.
2Measurement precision
If the exposure time is reduced to minimize transient periods, then measurement accuracy improves, but the system complexity increases to control rapid insertion and removal
Solution Approach 1:
The loading chamber and test chamber are merged into a single integrated system with shared walls and valve controls. The movable valve element serves dual purposes: isolating the test chamber during loading and then opening it to introduce the biological indicator. This merging reduces the number of separate mechanisms needed while enabling rapid, precise control of exposure timing.
Solution Approach 2:
The movable valve element and indicator holder assembly serve multiple functions: loading the biological indicator, isolating the test chamber during sterilant generation, introducing the indicator at the optimal moment, and enabling rapid removal. This multi-functionality reduces overall system complexity by consolidating multiple operations into a single integrated mechanism.
3Loss of time
If rapid insertion and removal of biological indicator is implemented, then transient exposure is minimized, but the valve mechanism and moving parts become more complex
Solution Approach 1:
The system is segmented into distinct functional zones: a loading chamber for indicator preparation, a test chamber for sterilization testing, and a movable valve element that controls communication between them. This segmentation allows each component to be optimized for its specific function while simplifying the overall control mechanism. The movable valve simply opens or closes the connection between chambers rather than requiring complex positioning.
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 system significantly reduces transient exposure periods, allowing for accurate determination of sterilant efficacy by minimizing errors in 'D' value measurements, especially for strong sterilants or weak biological indicators, and enables abrupt termination of sterilant exposure upon removal, enhancing the reliability of sterilization process evaluations.
Implementation Method 1
A sterilant vapor supply system is connected to the inlet port and the outlet port of the test chamber for supplying a sterilant vapor to the test chamber to establish a sterilizing environment in the test chamber
Data Source
AI summary
An apparatus for testing the efficacy of a sterilizing environment on a test indicator, comprising a test chamber, a loading chamber adjacent to the test chamber and an opening connecting the test chamber to the loading chamber. A movable gate mechanism has a first position closing the opening and isolating the test chamber from the loading chamber, and a second position wherein the opening connects the test chamber to the loading chamber. A system is connected to the inlet port and the outlet port of the test chamber for supplying a sterilant vapor to the test chamber to establish a sterilizing environment in the test chamber. An indicator holder is operable to move a test indicator from the loading chamber into and out of the test chamber when the gate mechanism is in the second position.