Ultraviolet irradiation is currently the most commonly used method of disinfection of air and surfaces, and it also has applications in the disinfection of water and other liquids. However, during the use of ultraviolet lamps, often due to ignorance of its mechanism of action or neglect of detection, it cannot make it play an effective role, and the expected bactericidal effect cannot be achieved. Here, a brief introduction to ultraviolet bactericidal lamps .
The origin of ultraviolet air disinfection. Early research began in the 1920s. It was first used in hospital operating rooms in 1936 and first used in schools in 1937 to control the spread of rubella.
The wavelength range is between 400-100 nm, divided into three bands: A, B, and C.Among them, the ultraviolet rays in the UV-C band (290-100nm) have the ability to kill bacteria, which is called disinfection ultraviolet rays. Ultraviolet bactericidal lamp is a special electric light source that directly uses ultraviolet rays (center wavelength is 253.7nm) to achieve the purpose of disinfection.
Ultraviolet disinfection lamp is a kind of low-pressure mercury lamp, which uses the ultraviolet light emitted by the intensified mercury vapor at lower pressure (<10-2Pa) to irradiate and disinfect. There are two main emission lines of ultraviolet bactericidal lamps : 253.7nm wavelength and 185nm wavelength, and the peak wavelength is 253.7nm. The ultraviolet rays of these two wavelengths can play a very good bactericidal effect. The former can directly act on the genetic material of biological cells, namely DNA, to damage the DNA and cause the death of bacteria, and has the function of decomposing ozone; the latter can pass through It reacts with oxygen in the air to produce ozone with strong oxidizing effect, thus killing bacteria.
The lamp tubes of ordinary fluorescent lamps and energy-saving lamps are made of ordinary glass, which cannot penetrate ultraviolet rays and emit visible light after being absorbed by fluorescent powder; while the lamp tubes of ultraviolet disinfection lamps are made of UV-transparent glass or quartz glass, and ultraviolet rays can pass through the glass tube. The wall shines through.The UV lamp is an incoherent light source, no interference will occur when two beams of ultraviolet light intersect.The radiation intensity of any point in the space radiation field formed by multiple ultraviolet lamps satisfies the principle of superposition.The ultraviolet radiation intensity at a certain point in the space is inversely proportional to the square of the distance from the ultraviolet lamp, so the disinfection effect of the ultraviolet lamp is mainly concentrated within the range of 1.0m.