Do you really understand the germicidal principle of UV lamps and requirements? Here I will take you into the world of ultraviolet lamps, together with his life and work.
1. Ultraviolet air disinfection origin
Early research on air disinfection began in the 1920s. 1936 began to be used in the operating room of the hospital, and 1937 was first used in schools to control the spread of rubella.
2. The wavelength of ultraviolet light
The wavelength ranges from 400-100 nm, and is divided into three bands, A, B, and C. Among them, UV-C band is the most common. Among them, the UV-C band (290-100 nm) of ultraviolet light has the ability to sterilize, known as disinfection UV. UV germicidal lamps directly using ultraviolet light (center wavelength of 253.7nm) to achieve the purpose of disinfection of the special light source.
3. Ultraviolet lamp disinfection principle
Ultraviolet disinfection lamp is a low-pressure mercury lamp, is the use of lower-pressure (<10-2Pa) mercury vapor is excited by the ultraviolet light emitted by irradiation disinfection of the lamp. Ultraviolet disinfection lamps have two main spectral lines: 253.7nm wavelength and 185nm wavelength, the peak wavelength of 253.7nm. These two wavelengths of ultraviolet light can play a very good bactericidal effect, of which the former can act directly on the genetic material of biological cells that is DNA, so that the DNA is damaged and lead to the death of bacteria, and has the function of decomposition of ozone; the latter can be through the role of oxygen and air, resulting in a strong oxidizing effect, the latter can have a strong oxidizing effect, the latter can have a strong oxidizing effect. The former can directly act on the genetic material of biological cells, that is, DNA, so that DNA is destroyed and bacteria die, and has the function of decomposing ozone; the latter can be produced by interacting with the oxygen in the air to produce ozone with strong oxidizing effect, thus killing bacteria.
4. Difference between UV disinfection lamps and ordinary fluorescent lamps and energy-saving lamps
Ordinary fluorescent lamps and energy-saving lamps are made of ordinary glass, which can not transmit ultraviolet rays, and emit visible light after being absorbed by the phosphor;
while the lamps of UV disinfection lamps are made of ultraviolet-transmitting glass or quartz glass, and the ultraviolet rays can pass through the wall of the tube to transmit out. UV lamp is a non-coherent light source, two beams of ultraviolet light will not produce interference when they intersect. The intensity of radiation at any point in the space radiation field formed by multiple UV lamps satisfies the principle of superposition. The intensity of ultraviolet radiation at a point in space is inversely proportional to the square of the distance to the ultraviolet lamp, so the disinfection of ultraviolet lamps is mainly concentrated in the 1.0m range.
4. Ultraviolet lamp installation requirements
The number of indoor suspended lamp installation (30W lamps, in the vertical 1m radiation intensity higher than 70μW/cm2) for an average of not less than 1.5W per cubic meter, and the requirements of a uniform distribution, suspended from the ground at a height of 1.8 ~ 2.2m, so that the human respiratory zone is in the effective irradiation range. Continuous irradiation of not less than 30min, ultraviolet radiation intensity and radiation distance is inversely proportional to the suspension is too high, affecting the sterilization effect.
5. Monitoring of ultraviolet lamps
The use of lamps in the daily record of irradiation time and cumulative irradiation time, a total of not less than 1000 hours. Monitor the radiation intensity every six months. When the radiation intensity is close to 70μW/cm2, the monitoring time needs to be shortened from the original semi-annual detection to monthly monitoring. New lamps should also be monitored before use, and can not be lower than 93μW/cm2.
6. Notes on the use of ultraviolet lamps
When sterilizing indoor air with ultraviolet lamps, the room should be kept clean and dry, and dust and water mist should be reduced. Temperature <20 ℃ or >40 ℃, or relative humidity >60%, should be appropriate to extend the irradiation time.
UV lamps should not be used to irradiate disinfection when there are people indoors.
In life, the lamp is a little clean gentleman. Therefore, you should keep the surface of the lamp clean, and wipe it once a week with 75% to 80% (v/v) ethanol cotton balls. Found that the surface of the lamp has dust, oil, should be wiped in time