Plasma-Activated Steam Sterilization for Low-Residue ROS Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sterilization methods using reactive oxygen species (ROS) such as super oxide radical, hydrogen peroxide, or hydroxy radical face challenges in optimizing conditions for producing and maintaining effective ROS, particularly in relation to the use of water or steam, leading to suboptimal sterilization efficacy and potential residue issues.
Innovation Solution
A sterilization apparatus and method that involves generating plasma using alternating current, mixing it with a water-containing gas heated to 50° to 300°C to produce a reactive oxygen species-containing gas with a water content equal to or greater than saturated steam, enhancing ROS production and sterilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous hydrogen peroxide or chemical sterilization is used, then sterilization is achieved, but chemical residues remain on surfaces
Solution Approach 1:
The invention changes the physical state of water from liquid (aqueous hydrogen peroxide) to gas phase (steam), and changes the chemical form from stable molecules to reactive radicals through plasma activation. This transformation eliminates chemical residues while maintaining sterilization efficacy through reactive oxygen species that decompose into water and oxygen.
Solution Approach 2:
The invention utilizes phase transition of water from liquid to steam, and the subsequent cooling and condensation of steam back to liquid water on the sterilized surface. This phase transition enables delivery of reactive oxygen species without leaving chemical residues, as the steam condenses into pure water.
2Reliability
If plasma is generated at high temperature to produce reactive oxygen species, then sterilization efficacy is improved, but the lifespan of reactive oxygen species decreases
Solution Approach 1:
The invention pre-heats the steam before it contacts the plasma, creating optimal conditions for reactive oxygen species generation. The pre-heated steam provides the necessary thermal energy to enhance plasma-water reactions while the controlled temperature ensures reactive oxygen species maintain sufficient lifespan for effective sterilization.
Solution Approach 2:
The invention optimizes the temperature parameter of steam (50-300°C) to balance two competing requirements: high enough temperature to enhance reactive oxygen species production through plasma interaction, but not so high that reactive oxygen species decompose too rapidly. This parameter optimization resolves the contradiction between efficacy and duration.
3Reliability
If steam is introduced into plasma to increase water content and reactive oxygen species production, then sterilization efficiency is improved, but control of water content becomes difficult
Solution Approach 1:
The invention controls the temperature of steam (50-300°C) and the flow rate ratio between plasma gas and steam to precisely control water content in the reactive oxygen species stream. By maintaining steam temperature above dew point and controlling mixing ratios, the invention achieves saturated steam conditions that maximize reactive oxygen species production while keeping water content within optimal ranges.
Data Source
Figure 1~2
AI summary
A sterilization apparatus characterized in that the sterilization apparatus comprises a reactive oxygen species irradiation unit for irradiating a reactive oxygen species-containing gas which is a reaction product of plasma generated using an alternating current and a water-containing gas containing steam, the sterilization apparatus further containing an inlet unit for steam flow for supplying the water-containing gas heated to a temperature of from 50° to 300°C, wherein the reactive oxygen species-containing gas contains water in an amount equal to or greater than the amount of saturated steam. The sterilization apparatus of the present invention shows excellent sterilization activity, so that it can be suitably used in sterilization of containers for foodstuff, bottle caps sealing the openings of the containers, medical devices, foodstuff such as vegetables and meat, and the like.