The killing rate of Staphylococcus aureus on the carrier was 100% when irradiated with the UVC lamp for 5 min at 2-5 cm vertically. The kill rate of E. coli on the carriers was 100% when irradiated for more than 15 min at 2-4 cm vertically. The intensity of UV radiation decreased from 9.2 μW/cm² to 1.9 μW/cm² as the irradiation distance was increased from 2 cm to 6 cm. The killing effect increased with increasing irradiation time at the same distance. There is good potential for the development of this type of UVC lamp. Let’s take a look at these experiments in detail.
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As a convenient and quick way of sterilization, germicidal UVC is currently one of the common means of sterilization in hospitals. However, there are certain problems in the use of traditional germicidal UVC equipment, such as high-power consumption, low luminous efficiency, 1 ordinary UVC lamp power is mostly 20 to 40W
[1] Germicidal UVC lamps mainly rely on the wavelength of 250 ~ 280 nm short-wave ultraviolet light (UVC), in addition to sterilization, but also to a certain degree of human health hazards
[2] With the rapid development of LED technology, the use of light-emitting diodes as a light source has become a powerful means of saving energy and extending the service life of lamps. Compared to ordinary UVC sterilizers, LED lamps use UVC semiconductors that emit a more concentrated range of wavelengths
[3]. Greatly improves This greatly improves the luminous efficiency and germicidal capacity and reduces power consumption. In this study, we chose The wavelength of 275 ± 5 nm and the output power is only 0.12 W. The germicidal effect of LED UV lamps and the factors affecting the In this study, the germicidal effect of LED UV sterilizer and the factors affecting the germicidal effect were observed in the laboratory.
1 Material and methods
1) Test materials
The UVC lamp used in the study was a Taiwanese product with a central wavelength of The central wavelength is 275 nm, the output power is 0.12 W, and the radiation intensity is 2.8 μm at an irradiation distance of 5 cm. The radiation intensity was 2.8 μW/cm² at an irradiation distance of 5 cm. The test organisms were Staphylococcus aureus (ATCC 25922) The test organisms were Staphylococcus aureus (ATCC 25922) and Escherichia coli (ATCC 25923). The test organisms were Staphylococcus aureus (ATCC 25922) and Escherichia coli (ATCC 25923), which were provided by the Strain Room of the Microbiology Department of Qingdao University School of Medicine. The culture media and related equipment were commercially available in China. The culture medium and related equipment were all commercially available in China.
Other test instruments include precision electronic balances, electric mixers, automatic double pure water stills, pressure steam sterilizers, electric thermostatic incubators, electric thermostatic blast drying ovens, etc.
2 Experimental results
1) UVC lamp effectiveness in killing Staphylococcus aureus
The results of the test showed that the LED ultraviolet line light irradiated at a vertical distance of 2-5 cm for 5 min had a 100% kill rate of Staphylococcus aureus on the infected carriers. The results showed that the UV lamp was 100% effective in killing Staphylococcus aureus on the carrier at a distance of 2-5 cm. The UV lamp increased the irradiation distance from 2 cm to 6 cm. The intensity of UV radiation increased from 9.2 μW/cm² to 9.2 μW/cm² as the irradiation distance increased from 2 cm to 6 cm. decreased from 9.2 μW/ cm² to 1.9 μW/cm²
2) E. coli killing effect
The results showed that the UV lamp irradiated at a vertical distance of 2 to 4 cm for more than 15 min achieved a 100% kill rate of E. coli on the carriers. The bactericidal effect increased with increasing irradiation time at each irradiation distance (Table 2).
3 Discussion
Compared with ordinary UV disinfection lamps, LED lamps have broad clinical application prospects due to their low-power consumption, high luminous efficiency, long life, and small size. The germicidal effect of LED lamps on Staphylococcus aureus and Escherichia coli in this trial was good. When the irradiation distance is less than 5 cm and the irradiation time is more than 5 min, the germicidal rate of Staphylococcus aureus reaches 100%; when the irradiation distance is less than 4 cm and the irradiation time is more than 15 min, the germicidal rate of E. coli reaches 100%. The germicidal effect of UVC lamps is generally considered to be closely related to the intensity, time, and distance of exposure. The results of this test show that the intensity of UV radiation from LED lamps decreases significantly with increasing vertical irradiation distance, so the germicidal effect of the lamp decreases significantly with increasing irradiation distance, while the germicidal effect increases with increasing irradiation time at the same irradiation distance. Therefore, the intensity of UV radiation is an important factor in the germicidal effect, and both the irradiation time and the irradiation distance will directly affect the germicidal effect of the lamp.
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