Sterilizer Pressure Control for Residual Water Removal
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Solution Overview
Problem
Conventional plasma gas sterilization methods face inefficiencies due to residual water blocking sterilant contact and freezing, leading to incomplete sterilization and health risks from residual sterilant absorption.
Innovation Solution
A method involving pressure control in a container to ensure residual water is efficiently drained and the sterilant effectively contacts the object, using pressure cycles above and below the triple point of water to prevent freezing and ensure thorough drying before sterilant injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the container is decompressed to below the triple point of water to vaporize residual water, then drying efficiency is improved, but residual water freezes and blocks sterilant contact
Solution Approach 1:
The patent applies preliminary action by performing decompression drying above the triple point of water before sterilant injection. This preliminary drying step removes residual water while preventing freezing, ensuring the object is adequately dried before the sterilization process begins, thus avoiding the problem of frozen water blocking sterilant contact.
Solution Approach 2:
The patent changes the pressure parameter by controlling it to remain above the triple point of water during the drying phase. This parameter control prevents phase change of residual water to ice, maintaining it in a vaporizable state while still achieving effective drying through controlled decompression.
2Reliability
If residual water remains on the object, then sterilant contact is blocked and sterilization is incomplete, but removing water by decompression causes freezing
Solution Approach 1:
The patent changes and controls the pressure parameter to remain above the triple point of water during the drying process. This prevents the phase change of residual water to ice while still achieving effective vaporization and removal of water, ensuring both sterilization completeness and proper water phase state.
3Reliability
If high pressure steam or high temperature dry heat is used for sterilization, then sterilization effectiveness is improved, but heat-sensitive objects are damaged
Solution Approach 1:
The patent changes the sterilization parameter from thermal (high temperature) to chemical (sterilant-based). By using sterilants that can effectively sterilize at lower temperatures, the method maintains sterilization effectiveness while eliminating thermal damage to heat-sensitive objects.
Solution Approach 2:
The patent substitutes the mechanical/thermal sterilization system (high pressure steam, dry heat) with a chemical sterilization system using sterilants. This replacement eliminates the harmful thermal effects while maintaining sterilization capability through chemical action.
4Adaptability or versatility
If electromagnetic radiation or EOG gas is used for sterilization, then applicability to various materials is improved, but aeration time increases and operational availability decreases
Solution Approach 1:
The patent changes the sterilization mechanism from physical (electromagnetic radiation, gas plasma) to chemical (sterilant vapor). This chemical approach provides broad material compatibility similar to EOG gas but eliminates the need for extended aeration time, as the sterilant directly contacts and sterilizes the object surface without requiring subsequent air exchange cycles.
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 enhances sterilant contact efficiency, minimizes residual sterilant, and prevents freezing, resulting in more effective and safer sterilization without the need for heated gases, simplifying the sterilization process.
Implementation Method 1
decreasing the pressure in the container to a first pressure which is equal to or more than the triple point pressure of water
Implementation Method 2
vaporize the residual water on the object
Data Source
AI summary
According to the present invention, a sterilant can be injected into a container without residual water on an object to be sterilized. The method includes decreasing a pressure in the container to a pressure higher than the triple point pressure at which water freezes. The method further includes comparing an actual time required for decreasing the pressure and a reference time, or comparing an actual rate of pressure increase and a reference rate to detect residual water on the object. If the residual water is detected, the pressure in the container is increased to the atmospheric pressure or the quasi-atmospheric pressure and the object is heated, and then the pressure is decreased to drain the residual water through the decompression boiling. The step of draining the residual water is repeatedly performed until no residual water is detected on the object and subsequently the sterilant is injected into the container.