Endoscope Flow Restrictor for Uniform Sterilant Distribution
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Solution Overview
Problem
Elongate medical devices with lumens, such as endoscopes, face challenges in sterilization due to pressure drops and debris accumulation, leading to uneven sterilant distribution and inadequate sterilization of smaller diameter channels during low-pressure sterilization processes.
Innovation Solution
A dry booster apparatus combined with a flow restrictor, comprising tubes of specific lengths and radii, is used to equalize the flow of sterilants through multiple lumens by adjusting the dimensions of the flow restrictor tubes based on the Hagen-Poiseuille equation to ensure even sterilant distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-pressure sterilization is used, then sterilization effectiveness is improved, but uneven sterilant distribution occurs in lumens of different diameters
Solution Approach 1:
The patent applies local quality by providing different flow restrictor tube dimensions for different lumens. Specifically, larger diameter lumens are equipped with flow restrictors having smaller radii and/or longer lengths, while smaller diameter lumens receive flow restrictors with larger radii and/or shorter lengths. This localized customization of flow restriction characteristics ensures that sterilant flow rates are equalized across lumens of varying sizes, resolving the uneven distribution problem while maintaining low-pressure sterilization effectiveness.
2Reliability
If pressure differential is increased to overcome pressure drop, then sterilant reaches all lumen surfaces, but flow rate through smaller diameter channels becomes insufficient
Solution Approach 1:
The patent applies parameter changes by systematically varying the flow restrictor tube parameters (radius and length) to control flow resistance. By adjusting these geometric parameters according to the Hagen-Poiseuille equation relationships, the system optimizes the balance between pressure differential requirements and flow rate maintenance. This allows sufficient pressure to overcome drops in all lumens while preventing excessive flow that would starve smaller channels.
3Productivity
If flow restrictor tube radius is decreased, then flow rate through larger lumens is reduced, but pressure drop increases
Solution Approach 1:
The patent applies local quality by customizing flow restrictor tube dimensions for each specific lumen configuration. Larger lumens receive flow restrictors with smaller radii to reduce their excessive flow, while the system accounts for the resulting pressure drop by appropriately sizing restrictors for smaller lumens. This localized optimization ensures that pressure differentials are distributed appropriately across all lumens, achieving flow rate control without creating unacceptable pressure drops in any single channel.
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 solution ensures that sterilants flow evenly through all channels of the endoscope, improving the sterilization efficacy by maintaining similar flow rates through channels of varying diameters, thereby enhancing the sterilization process.
Implementation Method 1
adjusting the dimensions of the flow restrictor tubes based on the Hagen-Poiseuille equation to ensure even sterilant distribution
Data Source
AI summary
An apparatus that assists in sterilizing an endoscope inside a sterilizer employing a gaseous sterilant, e.g., hydrogen peroxide, is disclosed. The apparatus may include a dry booster and a flow restrictor that includes two tubes, which may be connected to channels of an endoscope and the dry booster. The flow restrictor may be used to change the flow rates through the channels to assist in delivering sterilant throughout the channels.