UV lamp irradiation intensity issues and UV illuminance meter
1. Problems with the irradiation intensity of ultraviolet lamps:
Almost 50_80% of the UV lamps in China have 70 uw/cm2 (at a distance of 1m). According to the requirements of the Ministry of Health's safety technical specifications, the pass rate is less than 50%. The irradiation intensity of some units' ultraviolet irradiation lamps is less than 70uw/cm2 (at a distance of 1m). .Some are even less than 40uw/cm2 and are still in use. You must know that each microorganism has its specific ultraviolet killing dose threshold. The dose (K) is the product of the irradiation intensity (I) and the irradiation time (t), K =It. It can be seen from the formula that high-intensity short-time or low-intensity long-term irradiation can achieve the same irradiation effect. However, if the ultraviolet intensity is less than 40uw/cm2, extending the irradiation time will not achieve satisfactory irradiation effect. , there is a problem of microbial damage repair, and the main purpose is to deliberately increase the irradiation intensity.
2. The spatial scope of ultraviolet irradiation:
Many units that use ultraviolet irradiation lamps ignore the effective spatial range of ultraviolet irradiation and only consider and calculate the plane area of irradiation. In addition to the area factor, each irradiated space has high or low heights, and the total spatial range varies. Small, when using illumination lamps, the total cubic space should be calculated and ultraviolet illumination lamps with corresponding power should be used. The effective illumination space range of a 30w illumination lamp should be less than 30 cubic meters. It is generally believed that the illumination lamp power for each cubic meter of space should be greater than 1 -1.5w, please pay attention during use.
3. Irradiation distance of lamp hanging:
When using an irradiation lamp, attention should be paid to the irradiation distance between the illuminated object and the irradiation lamp, that is, the suspension height of the lamp tube should be less than 2.5 meters. Some units use lamps with a suspension height greater than 2.5 meters, or even greater than 3 or 4 meters. Ultraviolet rays The irradiation intensity is almost inversely proportional to the irradiation distance. If it is hung too high, it will inevitably affect the irradiation effect.
4. UV radiation intensity decline problem:
As the use time of ultraviolet irradiation lamps increases, the radiation intensity will gradually decline. According to various measurements, after 1000 hours of use of quartz lamps, the decline rate is less than 20%, while after 200 hours of use of high boron lamps, the decline rate is greater than 30% , and the irradiation intensity of the high boron lamp itself is less than 70uw/cm2, so quartz ultraviolet irradiation lamps should be used. The main characteristics of quartz ultraviolet irradiation lamps are high irradiation intensity and slow decay. The raw material of the quartz lamp tube is natural crystal stone, with a violet transmission rate of more than 80%, while the violet transmission rate of high boron glass is less than 50%, and the violet transmission rate is less than 50%. The rate is low and the irradiation intensity is also low.
