Issues with Ultraviolet Lamp Irradiation Intensity and Ultraviolet Lux Meters
Many units using ultraviolet (UV) lamps neglect the effective spatial range of UV irradiation and only consider and calculate the planar area of irradiation. For each spatial area, in addition to the area factor, the height varies, and the total spatial range differs in size. When using UV lamps, the total cubic space should be calculated, and UV lamps with corresponding power should be selected. The effective spatial range of a 30W UV lamp should be less than 30 cubic meters. It is generally believed that the power of the UV lamp per cubic meter of space should be greater than 1-1.5W, which should be noted during use.
Irradiation Distance for Lamp Hanging:
When using UV lamps, attention should be paid to the irradiation distance between the object and the lamp, that is, the hanging height of the lamp tube should be less than 2.5 meters. Some user units hang the lamp tubes at heights greater than 2.5 meters, and some even exceed 3 or 4 meters. The UV irradiation intensity is nearly inversely proportional to the irradiation distance. If the hanging height is too high, it will inevitably affect the irradiation effect.
Issue of Ultraviolet Irradiation Intensity Degradation:
As the usage time of UV lamps prolongs, their irradiation intensity gradually degrades. Multiple measurements show that after 1,000 hours of use, the degradation rate of quartz lamp tubes is less than 20%, while that of high-boron lamp tubes exceeds 30% after only 200 hours of use. Additionally, the inherent irradiation intensity of high-boron lamp tubes is less than 70 μW/cm². Therefore, quartz UV lamp tubes should be selected for use. The main characteristics of quartz UV lamps are high irradiation intensity and slow degradation. Quartz lamp tubes are made from natural crystal stones, with a UV transmittance of over 80%, whereas the UV transmittance of high-boron glass is less than 50%. Lower UV transmittance directly results in lower irradiation intensity.
