Analysis and research on radiation energy and sterilization effect of air filters

According to the production and design personnel of air filters and other related purification equipment, radiation energy is expressed by radiation output, radiation intensity and radiation amount. Radiation output is the energy radiated by the radiator per unit time, which is equivalent to the luminous flux of a fluorescent tube; radiation intensity is the radiation output per unit area; radiation amount is the product of radiation intensity and radiation time.

The radiation output capacity varies with the temperature, humidity, wind speed and other factors of its application environment. The output capacity is low when the ambient temperature is low. The sterilization effect will also decrease with the increase of humidity. Ultraviolet lamps are usually designed based on a relative humidity of 60%. When the indoor humidity increases, the sterilization effect decreases, and the irradiation amount should also increase accordingly. For example, when the humidity is 70%, 80%, and 90%, in order to achieve the same sterilization effect, the radiation amount needs to be increased by 50%, 80%, and 90% respectively. The wind speed also affects the output capacity. In addition, because the sterilization effect of ultraviolet lamps varies with different strains, the amount of ultraviolet radiation should be changed for different strains. For example, the amount of radiation for killing molds is 40 to 50 times greater than that for killing bacteria. 

The radiation intensity of ultraviolet lamps weakens with the increase of irradiation distance. Taking the test data of a 30W ultraviolet lamp produced by a certain factory as an example, the radiation intensity is 72uw/cm2 when the radiation distance is 1m, 19.5uw/cm2 when the distance is 2m, and 8um/cm2 when the distance is 3m. Therefore, when considering the sterilization effect of ultraviolet sterilization lamps, the influence of the installation height on it cannot be ignored.

The sterilization power of ultraviolet lamps decreases with the increase of use time. The output power of 100h is the rated output power, and the lighting time of the ultraviolet lamp to 70% of the rated power is the average life. When the use time of ultraviolet lamps exceeds the average life, the expected effect cannot be achieved. At this time, it is necessary to replace it. Generally, the average life of domestic ultraviolet lamps is 2000h.

The sterilization effect of ultraviolet rays is determined by its radiation dose, and the radiation dose is always equal to the radiation intensity multiplied by the radiation time. Therefore, to improve the radiation effect, it is necessary to increase the radiation intensity or extend the radiation time.