The sterilization lamp is actually a low pressure mercury lamp. The low pressure mercury lamp is used to emit ultraviolet light by the activation of lower mercury vapor pressure (< 10-2Pa). There are two main emission lines: one is 253.7nm wavelength; the other is 185nm wavelength, both of which are invisible ultraviolet rays.
The fluorescent lamp and energy saving lamp used for lighting are also low-pressure mercury lamps. Ultraviolet rays are emitted after being excited by low-pressure mercury vapor. Ultraviolet light with 254nm wavelength will shine on the phosphor and then emit visible light. If the composition and proportion of fluorescent powder are changed, it can emit different colors of light we normally see.
The sterilization lamp does not need to be converted into visible light, and the wavelength of 253.7nm can play a good bactericidal effect. This is because the cell has a rule on the absorption spectrum line of light wave. The ultraviolet rays at 250-270nm have the maximum absorption. The absorbed ultraviolet rays actually act on the cell genetic material, namely DNA, which plays a photochemical role. The energy of ultraviolet photons is affected by DNA The base pair absorption in the, causing genetic material variation, so that the bacteria immediately die or can not reproduce offspring, to achieve the purpose of sterilization.
Fluorescent and energy saving lamps are made of ordinary glass. UV rays of 253.7nm cannot be transmitted out. They cannot be used as sterilization lamps. Quartz glass has high UV transmittance, reaching 90% is the best material for sterilization lamp. However, the performance of quartz glass is very different from that of ordinary glass (mainly the coefficient of thermal expansion is different). Sealing can not be done by the method of circular sealing with high automation, which makes the technical content of the production and manufacture of sterilization lamp higher than that of ordinary energy saving lamp.
There is a kind of glass with ultraviolet rays, that is, the high boron glass, which has about 60% of the ultraviolet transmittance of quartz glass. Its production process is the same as energy saving lamp, which makes its cost and price far different from that of quartz glass. The lamp tube of several watts only needs several yuan, but it is far less than quartz sterilization lamp in performance. The following aspects are shown:
1. The UV intensity of quartz glass sterilization lamp is more than 1.5 times higher than that of high boron glass sterilizer after the same ballast test;
2. The UV intensity of high boron glass lamp is easy to decay. After it lights for hundreds of hours, its UV intensity will drop sharply, which is 50% - 70% of the initial value. In the user's hand, although the light tube is still on, it may not work. The attenuation degree of quartz glass is much smaller than that of high boron lamp. If the production process passes, the light attenuation of quartz lamp is 2000-3000 hours after lighting, and the light attenuation will reach 80% - 70% of the initial time. In the future, as long as the lamp is not off, the range of light decline will be smaller and smaller.
3. Customers of domestic sterilization lamps may know Philip's sterilization lamps. Philip has a sterilization lamp made of glass close to ordinary glass, rather than quartz glass. Its transmittance is close to the transmittance of quartz glass, It is much higher than that of China, and can be produced by energy saving lamp production technology with high automation. This lamp mainly depends on their technology of refining this glass. Its disadvantage is that ozone cannot be produced.
4. Another feature of quartz germicidal lamps is the ozone emission. Because quartz glass has high UV transmittance to 185nm in short wave, 185nm ultraviolet rays can ionize air to produce ozone, and high ozone concentration is not good for human body. But it can be used in unmanned occasions. Ozone can also be sterilized and sterilized. It can make up for the disadvantage that ultraviolet rays only spread in a straight line and disinfect with dead angle.
In some cases, ozone is not allowed, and quartz sterilization lamp can be used. Titanium (TI) is added to the quartz glass when refining, which makes it cut off under 200nm through ultraviolet rays, but has no effect on the transmission of 254nm ultraviolet rays, that is, generally called ozone free sterilization lamp.
From the above analysis, it is the best choice to use quartz glass as germicidal lamp. In China, high boron sterilization lamps are not recommended in the field of medical and health. Quartz glass is widely used in the production of ultraviolet lamps in the United States, Canada and Japan. However, the sterilizer lamp produced by quartz glass is not necessarily good, because two major problems need to be solved.
1. As mentioned above, because of the special properties of quartz glass, the production of quartz germicidal lamp cannot be large-scale and mechanized, but only by hand, which makes the cost of quartz sterilization lamp higher. Domestic manufacturers produce dozens of UV sterilization lamps, foreign imports of China to hundreds of yuan or even hundreds of yuan. High price, hindering its further push from the above analysis, as a sterilization lamp quartz glass is the best choice. In China, high boron sterilization lamps are not recommended in the field of medical and health. Quartz glass is widely used in the production of ultraviolet lamps in the United States, Canada and Japan.
2. The light decay is large - quartz sterilization lamp may also have a problem - the life is not long. There are two concepts for short life: one is that the lamp is not long, that is, it will not be long to point, and the lamp is off, which is mainly due to the poor electrode treatment. In the process of quartz processing, high temperature is needed. If the treatment is not correct, the cathode will be damaged, and the lamp will be off for a period of time; the second concept refers to the effective life. Even if the lamp does not turn off, its UV light intensity will decay rapidly to 30%, and the lamp will be considered to be dead according to the industry standard yy/t060-94. Yy/t060-94 stipulates that the effective life of quartz sterilization lamp must be more than 1000 hours, while that of American and Japanese lamps passing relevant standard sterilization lamps is more than 9000 hours. Obviously, the quality level of ultraviolet lamp in China is much lower than that of foreign ones.
Cnlight.Com According to this situation, the research on high-intensity and long-life UV low pressure mercury lamp (commonly referred to as sterilization lamp) began in early 2000. After more than a year of efforts, we have overcome this subject and we have determined the advantages in the following two aspects.
1、 At present, the cost of quartz sterilization lamps is mainly manual, especially the main process, sealing is manual, which makes the product cost generally high, the consistency of products is poor, and the reliability is difficult to guarantee. The problem that is easy to appear is chronic air leakage, the main reason for the chronic leakage is that the sealing of quartz and electrode is not good. With the automatic sealing method, Huaxing has greatly improved the production efficiency and finished product rate, with air leakage less than 0.5%, and the reliability is greatly improved, and the unit cost is significantly lower than that of the peers, and the price has a strong competitiveness.
2、 The effective life of quartz sterilization lamp produced by the manufacturer is no problem in the number of lighting points. However, it can not be used when the lamp tube is not turned off. For example, 30 Watt quartz disinfection lamp used in hospital is generally 100 μ w/cm2 (1.0m) after a period of time (about 1500 hours), and then measured with ultraviolet probe (at 1.0 m) At the moment, the lamp tube should be replaced to avoid the poor disinfection effect.
The reason for the light attenuation of ultraviolet light intensity is very complex from the mechanism. There is a mature understanding of the light decay of fluorescent lamps (such as energy saving lamps), such as Fudan University in 1999 and Cnlight.Com The first prize awarded by the Ministry of education was awarded by the Ministry of education for the cooperative research on the analysis of the light failure mechanism of compact energy saving lamps. But the mechanism of the photoluminescence and the fluorescent light decay of the quartz ultraviolet lamp is not exactly the same. Because the processing process of quartz glass and fluorescent lamp is different, the quartz glass needs to be sealed at high temperature; secondly, the quartz glass itself and ordinary glass are different in its raw materials and production process, and their properties are much different, which has a certain influence on the UV light decay.
The technology development center of Huaxing optoelectronic Co., Ltd. is further deepening the research on the mechanism of "the fading mechanism of UV light", but it has been very effective and reliable to reduce the UV light decay.
This method is treated with special treatment, so that the intensity attenuation of ultraviolet light is reduced by only about 20% during the whole life. For example, the UV intensity of 30 watt lamp is 100 μ w/cm2 (1.0m), and even if the point reaches 6000 hours, the UV intensity of 30W lamp is 80-90 μ w/cm27000 hours, and the UV intensity of 254nm is more than 70 μ w/ cm2. This technology has similar application in Philips. It makes it possible to use ultraviolet lamp for long life.
Ultraviolet lamp is generally used to sterilize air, surface and water. 254nm wavelength can kill bacteria and viruses effectively. Many researches have been done before, which is a fact without doubt. Ultraviolet sterilization is characterized by wide spectrum, some viruses which are difficult to eliminate at high temperature. Ultraviolet rays can be quickly eliminated, which is due to the different sterilization mechanism of ultraviolet rays from other methods.
The killing of bacteria and viruses by ultraviolet rays is related to the UV irradiation dose. The irradiation dose = irradiation time (s) × irradiation intensity (μ w/cm2). Generally speaking, the design requirements of irradiation dose are greater than 30000 μ w/cm2. If the ultraviolet intensity is low, the same effect can be achieved with the higher intensity as long as the time is long. If the time is not allowed for a long time, the radiation dose can achieve the same effect as that of the higher intensity, High intensity and high power ultraviolet lamps are required. In general, the irradiation dose of various bacteria and viruses is different. When the irradiation intensity is measured at the killing point, the irradiation time can be calculated. If the sterilized object is not known, the irradiation time is generally extended to ensure the sterilization efficiency. Because ultraviolet rays can kill cells, it is necessary to pay attention to the fact that ultraviolet rays cannot directly affect the skin of human, especially the eyes of people. When the ultraviolet sterilization lamp is on, do not look directly at the lamp tube. Because short wave ultraviolet rays do not pass through ordinary glass, glasses can avoid eye injury. If you accidentally hurt your eyes, it is not a big obstacle. As if you are burned by the sun, you can drop eye drops or human milk to help recover. In some cases, do not use ozone lamp tubes, when ozone concentration is high, it is not good for people.
Ultraviolet disinfection and sterilization is widely used. Hospitals, schools, nurseries, cinemas, buses, offices, families, etc. it can purify air and eliminate mildew smell. A certain amount of negative oxygen ions can be produced outside the secondary. The air in the rooms sterilized by ultraviolet rays is particularly fresh. In public, ultraviolet disinfection can avoid some pathogens from air or through the surface of the object. The application of long-life ultraviolet lamp in water disinfection and environmental protection engineering is of great significance. Water disinfection equipment such as pure water system generally operates in 24 hours. The life and reliability of UV sterilizer lamps are required to be high. If the lamp tube has a short life, it is very difficult to replace the lamp tube.
The application of ultraviolet lamp in water disinfection has been popular in western countries in the 1980s and implemented in China in the 1990s. It has incomparable advantages over the traditional chlorine disinfection. Chlorine disinfection: it will form a chlorine compound in water, which is a carcinogen, and there will be a taste when the chlorine concentration is high. If you drink raw water, you will obviously smell this strange smell. There is still another way to disinfect water: ozone and ozone can also be sterilized. However, when the concentration is high, the time of ozone decomposition will be prolonged, and it will probably be transported to the residential room through close-distance pipelines. Ozone water is said to be able to beautify and wash dishes, but it can't be drunk and it tastes bad. If the concentration is reduced, the bactericidal ability will be weakened. In addition, ozone disinfection should prevent leakage.
Therefore, UV sterilization has incomparable advantages in water disinfection: UV intensity can be measured and monitored, online control can be achieved, disinfection effect can be understood in time, and there will be no side effects, and there is an immeasurable prospect in the field of water disinfection.
