Ultraviolet lamp irradiation intensity problem
1, The issue of irradiation intensity of ultraviolet lamps:
Almost 50-80% of our country's ultraviolet lamps have a capacity of 70 uw/cm2 (at a distance of 1m), and according to the technical specifications of the Ministry of Health, the pass rate is less than 50% Some units use ultraviolet lamps with irradiation intensity less than 70uw/cm2 (at 1m) Some even use less than 40uw/cm2 You should know that each microorganism has its specific UV killing dose threshold Dose (K) is the product of irradiation intensity (I) and irradiation time (t), K=It. From the equation, it can be seen that high-intensity short-term or low-intensity long-term irradiation can achieve the same * * effect However, if the UV intensity is less than 40uw/cm2, extending the irradiation time will not achieve satisfactory results, and there is a problem of microbial damage repair in between. Deliberately increasing the irradiation intensity is the main approach
2, The issue of spatial range of ultraviolet radiation:
Many UV lamp users ignore the effective spatial range of UV irradiation and only consider and calculate the planar area of irradiation Each space, in addition to area factors, has varying heights and total spatial ranges. When using lamps, the total cubic space should be calculated using ultraviolet lamps of corresponding power. The effective spatial range of a 300000 watt lamp should be less than 30 cubic meters. It is generally believed that the lamp power per cubic meter of space should be greater than 1-1.5 watts, and attention should be paid during use.
3, Radiation distance of lamp hanging:
When using a searchlight, attention should be paid to the irradiation distance between the illuminated object and the searchlight, that is, the hanging height of the lamp tube should be less than 2.5 meters. Some units use lamps with a hanging height greater than 2.5 meters, or even greater than 3 or 4 meters The intensity of ultraviolet radiation is almost inversely proportional to the irradiation distance, and hanging too high will inevitably affect the effectiveness of the detection.
4, The problem of UV radiation intensity degradation:
As the usage time of ultraviolet searchlights increases, the irradiation intensity will gradually decrease After multiple tests, the decay rate of quartz lamps is less than 20% after 1000 hours of use, while the decay rate of high boron lamps is greater than 30% after 200 hours of use. In addition, the irradiation intensity of high boron lamps themselves is less than 70uw/cm2. Therefore, quartz ultraviolet probe lamps should be selected for use. The characteristics of quartz ultraviolet searchlights are mainly high irradiation intensity and slow decay The raw material of quartz lamp tube is natural crystal stone, with a transmittance of over 80%, while the transmittance of high boron glass is less than 50%, with low transmittance and low irradiation intensity. Exploration and illumination
5, Attention should also be paid to wiping and cleaning the lamp tube in the application:
When using a new lamp, you can first wipe the lamp tube with 75% alcohol gauze to prevent dust and oil stains from contaminating the lamp tube During use, regularly wipe and clean the lamp tube to avoid affecting the transmittance and radiation intensity.
