Face Mask Sterilization with Electromagnetically Shielded Containers
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Solution Overview
Problem
Existing methods of sterilizing N95 and similar filtering facepiece respirators using ionizing radiation, such as electron beam, X-ray, and gamma radiation, compromise the electrostatic properties of polypropylene nanofiber filters, leading to reduced filtration efficiency, making them unsuitable for reuse.
Innovation Solution
The use of electromagnetically shielded containers, such as metal or metalized bags, to protect the electrostatic properties of the filters during ionizing radiation sterilization, ensuring the filtration efficiency is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ionizing radiation (E-beam, X-ray, gamma) is used to sterilize FFRs, then sterilization effectiveness is improved, but filtration efficiency is reduced to 45%-65%
Solution Approach 1:
A polyethylene terephthalate (PET) intermediary layer is introduced between the ionizing radiation source and the polypropylene filtration media. This PET layer absorbs the ionizing radiation energy and converts it to a form that can sterilize the FFR without directly damaging the electrostatic properties of the PP nanofibers, thereby maintaining filtration efficiency while achieving sterilization
2Reliability
If traditional ionizing irradiation methods are used on FFRs in packaging, then sterilization is achieved, but electrostatic properties of PP are significantly adversely affected
Solution Approach 1:
The PET layer serves as a protective intermediary that mediates the interaction between ionizing radiation and the PP electrostatic charge. It absorbs the harmful radiation energy before it can directly ionize and neutralize the electrostatic charges on the PP nanofibers, thus preserving the electrostatic properties while still enabling sterilization
Solution Approach 2:
The PET intermediary layer is positioned in advance before radiation exposure to preemptively block and absorb the ionizing radiation. This preliminary protective action prevents the radiation from directly interacting with and damaging the electrostatic properties of the PP filtration media
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 filtration efficiency of the respirators is preserved, achieving effective sterilization without significant degradation of the electrostatic properties, allowing for safe reuse.
Implementation Method 1
applying sterilizing ionizing radiation to the personal protective mask or mask filter
Implementation Method 2
This sterilizing ionizing radiation is preferably at least one of e-beam radiation, x-ray radiation, and/or gamma radiation
Implementation Method 3
The use of electromagnetically shielded containers, such as metal or metalized bags, to protect the electrostatic properties of the filters during ionizing radiation sterilization
Implementation Method 4
N95 rated FFR's have a nonwoven fabric filtration media of polypropylene (PP) nanofibers that are imbued with an electrostatic trait upon manufacture, usually via a meltblown process
Implementation Method 5
the electrostatic properties of PP, lowering the filtration efficiency beyond acceptable limits
Data Source
AI summary
A method of disinfecting personal protective masks and mask filters, includes the step of applying sterilizing ionizing radiation to the personal protective mask while it is disposed in an electromagnetically shielded container.