The use of short-wave UV lamps should pay attention to the irradiation distance between the disinfected object and the short-wave UV lamp, that is, the lamp should be hung at a height of fewer than 2.5 meters, some units use a lamp hanging height greater than 2.5 meters, or even greater than 3,4 meters. UV irradiation intensity and irradiation distance are almost inversely proportional, hanging too high, is bound to affect the effect of sterilization.
Germicidal principle of short-wave UV lamps
UVC is a light wave invisible to the naked eye, that exists on the outside of the ultraviolet end of the spectrum, so-called ultraviolet, according to the different wavelength range, was cut into A, B, C three wavelengths, of which the C band of ultraviolet wavelengths between 240-260nm, the most effective germicidal wavelengths, wavelengths in the strongest point is 253.7nm.
|Spectral diagram of short-wave UV lamps|
Modern UV disinfection technology is based on modern epidemiology, optics, biology, and physical chemistry, using specially designed high-efficiency, high-intensity, and long-life C-band UV light-generating devices to produce strong UV-C light irradiation of flowing water (air or solid surface), when various bacteria, viruses, parasites, algae and other pathogens in the water (air or solid surface) are exposed to a certain dose of UV-C When the water (air or solid surface) is exposed to a certain dose of UV-C radiation, the DNA structure in its cells is destroyed, thus killing bacteria, viruses and other pathogens in the water without the use of any chemicals, and achieving the purpose of disinfection and purification.
|Ultraviolet disinfection technology principle|
UV-C wavelengths inactivate microorganisms by destroying their DNA structure so that they cannot reproduce. The use of UVGI in air disinfection dates back to the 1940s when it was used to control the spread of tuberculosis in hospitals. Today, UVGI air disinfection has evolved to include sophisticated systems for air disinfection in residential, hospital, commercial and industrial buildings and public facilities such as airports. The types of UVGI air disinfection systems currently in use include single-compartment recirculation units that can be moved or wall-mounted as overhead units, as well as duct-mounted systems for heating, ventilation, and air conditioning (HVAC) systems. 254 nm UV wavelength (known as ultraviolet germicidal radiation (UVGI)) is widely used in industry to inactivate a variety of microorganisms such as bacteria, viruses, and molds. Therefore, the use of UVGI in PCO systems serves the dual purpose of activating photocatalysts and microbial disinfection.
Applications of short-wave UV lamps
1. Application in surface sterilization, UV surface sterilization devices are widely used in food, electronics, semiconductors, liquid crystal displays, plasma TVs, crystal vibrators, precision devices, chemicals, medicine, health care, biology, beverages, agriculture, and other fields. Short-wave UV lamps irradiate food, materials, and other surfaces with a fast and efficient, non-polluting sterilization effect, thus maintaining the high quality of the product. Compared with traditional sterilization methods, surface sterilization has the characteristics of fast sterilization speed, continuous processing and batch processing, simple operation, environmental protection, and no secondary pollution.
2. Application in water treatment. The use of short-wave ultraviolet lamps for water treatment has two methods, submerged and overflow type, directly into the water, called submerged type; UV lamps into the casing used, called overflow type. At present, the main method used is the over-flow method. The working principle of over-flow type equipment is to produce a certain flow rate of water by the pump pressure, flowing through the periphery of the quartz casing that can transmit ultraviolet light, and the ultraviolet lamp produces ultraviolet light to disinfect and sterilize the water. The characteristics of the water flow are very fast, generally the quartz jacket flow through the time for no more than 1s, so the UV intensity of the short-wave UV lamp is required to be very high.
3. Application in medical sanitation. The use of short-wave UV lamps to sterilize the air in hospitals has a history of decades, there are static air direct irradiation methods and mobile air disinfection methods. Static air direct irradiation method using UV disinfection lamp direct irradiation, the disadvantage is that the irradiation can not be disinfected in places, disinfection can not be present when people. Mobile air disinfection method using dynamic air disinfection machine, this disinfection machine can just make up for the above two defects. The working principle of mobile air disinfection machine is through indoor air circulation, sterilization of the air through the disinfection machine, so as to achieve the purpose of disinfection of the entire indoor air. The structure of this type of disinfection machine is mostly taken from the shell of the indoor unit of a household air conditioner. The mobile air disinfector has now developed into a variety of disinfection equipment, including germicidal air conditioners and air purifiers. The use of the product is also popularized, which used to be used only in hospitals, but now goes to homes, offices, and announcement places. The function is also diversified, the product used to sterilize only can now be used for health care, preventive role, become health-related products
4. Sanitation and aseptic disinfection are necessary requirements when producing and processing filled and packaged foods. Sterilization with UV lamps is a commonly used cost-effective and extremely environmentally friendly alternative to the frequent use of chemical processes.
Surface disinfection of packaging materials: In a filling plant, bacteria on the surface are killed by the short-wave UV-C radiation to which they are exposed. The degree of packaging material purity is used to determine if the packaging material is substandard packaging.
For example, UV disinfection would be applied to filling machines for dairy products and beverages, lids, cups, covers, and foil-wrapped beverages as well as to the refrigeration of dairy and other food products. Due to the use of UV disinfection technology, short-wave UV lamps can extend the shelf life of food products.
On conveyor belts: Applications in the transport of meat, fish, potato products, fruits, and vegetables. To further improve the economic effect it is necessary to further strengthen the hygiene process during food processing.
Food surface disinfection: for example, surface disinfection of fruit and vegetable products and hard cheese.
|Tepro UV Lamps|
The use of short-wave UV lamps need to pay attention to the problem
First, the UV lamp irradiation intensity problem:
China's UV lamps 70 UW/cm2 (1m distance at) almost 50_80%, compared to the requirements of the Ministry of Health disinfection specifications, the qualified rate of less than 50%. Some units use short-wave UV lamps with an irradiation intensity of less than 70uw/cm2 (1m at). Some are even less than 40uw/cm2 is still in use. It is important to know that each microorganism has its own specific UV killing dose threshold. Germicidal dose (K) is the product of irradiation intensity (I) and irradiation time (t), K = It. From the formula can be seen that high-intensity short time or low-intensity long time irradiation can obtain the same sterilization effect. However, if the UV intensity is less than 40uw/cm2, then the extended irradiation time can not play a satisfactory sterilization effect, there is the problem of microbial damage repair, deliberately increasing the irradiation intensity of the main
Second, the space range of UV irradiation problem:
Many short-wave UV lamps use units that ignore the effective spatial range of UV irradiation, only consider and calculate the irradiation plane area. For each disinfection space, in addition to the area factor, the height has high and low, the total space range has large and small, the use of short-wave UV lamps should calculate the total space cube using the corresponding power of short-wave UV lamps, a 30w short-wave UV lamps effective sterilization space range should be less than 30 cubic meters, it is generally believed that each cubic meter of space short-wave UV lamp power should be greater than 1-1.5w, in use should Attention should be drawn to.
Third, the irradiation distance of the lamp suspension:
The use of short-wave ultraviolet lamps should pay attention to the irradiation distance between the disinfected object and the short-wave ultraviolet lamp, that is, the suspension height of the lamp should be less than 2.5 meters, some units use a lamp suspension height greater than 2.5 meters, or even greater than 3,4 meters are available. UV irradiation intensity and irradiation distance is almost inversely proportional, hanging too high, is bound to affect the effect of sterilization.
Fourth, the decline in UV irradiation intensity problem:
In short-wave ultraviolet lamps with the use of time, irradiation intensity will gradually decline. Measured by many, quartz lamp after 1000 hours of use, a decline rate of less than 20%, and high boron lamp after 200 hours of use, the decline rate of more than 30%, plus high boron lamp itself irradiation intensity is less than 70uw/cm2, so the use of quartz short-wave UV lamps should be selected.
The characteristics of quartz short-wave ultraviolet lamps, are mainly high irradiation intensity, slow recession. Quartz lamp raw materials are used in natural crystal stone, purple rate of more than 80%, while the high boron glass purple rate of less than 50%, low purple rate, irradiation intensity is also low.
Fifth, the application should also pay attention to the wipe and cleaning of the lamp:
When using the new lamp, you can first wipe the lamp with 75% alcohol gauze to remove dust and oil pollution from the lamp. In the process of use, regular wipe, do a good job of cleaning the lamp, so as not to affect the transmission rate and radiation intensity of the purple.
Six, the use of short-wave UV lamps should also pay attention to prevent UV radiation damage:
Mainly to prevent UV radiation damage to the eyes, face parts, especially attention to the conjunctiva of the eye radiation damage. Face by radiation damage, eye redness, swelling, tears, stinging, more serious than electric eye damage. It takes three or four days to heal. (In case the conjunctiva is damaged by ultraviolet radiation, use human milk drops, once every half hour, three to four times for better results). Prevention methods: to avoid facing the light source, in the short-wave ultraviolet lamp radiation intensity monitoring review, with special irradiation intensity or sunglasses as a protective mask, protective glasses, but do not use quartz glass as raw materials for the production of protective equipment, because the quartz glass to an ultraviolet light transmission rate of more than 80%, while ordinary glass to ultraviolet light can hardly transmit, can effectively prevent ultraviolet radiation damage.
Seven, strengthen the monitoring of short-wave UV lamp irradiation intensity:
The application of ultraviolet disinfection is vital to work. The use of units in the use of short-wave ultraviolet lamps should be three to six months with irradiation meter for an intensity test, health epidemic monitoring department should be every six months (one year two) to use short-wave ultraviolet lamp units for intensity monitoring, found that the intensity of the lamp should be replaced in a timely manner. Ultraviolet irradiation meter should be required to make an annual measurement calibration to ensure its accuracy, monitoring the irradiation intensity, the need to measure the conditions in accordance with the Ministry of Health technical specifications, voltage 220V, temperature 20'C, RH < 60% for monitoring, five minutes after the light is turned on the stable intensity of the measured short-wave ultraviolet lamp irradiation intensity.
Eight, attention should be paid to the quality of short-wave UV lamps to assess the impact of factors:
UV lamp quality assessment standards are mainly based on the Ministry of Health disinfection technical specifications, that is, the relevant provisions of the irradiation intensity. The irradiation intensity of the lamp meets the requirements, and will certainly have a satisfactory sterilization effect. However, the irradiation intensity of the lamp the determination by a number of factors: whether the Ministry of Health disinfection technical specifications for the determination of the conditions of ultraviolet intensity irradiation meter is standard ballast power deviation of the quality of the glow starter are all factors affecting the assessment of the intensity of the lamp. Attention should be drawn to the use of.
In addition, the quartz glass tube to various wavelengths of ultraviolet light: A glass, B glass, C glass, and vacuum glass can be transmitted, which 185nm can produce ozone, and in the fused quartz glass tube, adding a trace of titanium oxide (0.01-0.05%) and 0.07% aluminum oxide, less than 200nm ultraviolet light can not be absorbed through the tube wall, the concentration of ozone is too high, harmful to humans, then in the personnel Low ozone short-wave UV lamps are used in the working environment. Ozone short-wave UV lamps, both high-intensity irradiation, but also a high concentration of ozone, and no sterilization of dead space, disinfection effect is better, no personnel work environment can choose ozone short-wave UV lamps to improve the sterilization effect. In general, different types of short-wave UV lamps should be selected according to different environments and needs.
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