Development of a UV Sterilizer

Abstract

This study proposes the development of a UV sterilizer to decontaminate N95 masks or medical devices. The study is in cooperation between the National Defence Studies Institute by the Military Technical Training School and King Mongkut’s University of Technology  North Bangkok. The design is based on adaptation of an electric oven, Imarflex IF 451. To become         a sterilizer, the oven is equipped with two 10 W-UV light sources at wavelength 253.7 nanometers. The sterilization effectiveness was testified by using Escherichia Coli bacterial contaminated on N95 masks. The results show that the UV sterilizer can decontaminate the mask within   1 minute. The effect of UV light on fibers of N95 masks was investigated by using the UV sterilizer with exposure time of 20 minutes. Scanning electron microscope images of the UV-exposed N95 masks reveal that contaminated N95 masks can be retreated by the UV sterilizer without damage of the mask fibers up to 10 times. The leakage of UV light from the sterilizer was examined. The measurement shows that the leakage of UV light is less than 1 microwatt per square centimeter. The sterilizer also passed the 18 checks of electrical safety testing that firmly ensure its electrical safety.