Increasingly serious environmental pollution air filter is widely used

With the increasingly serious environmental pollution and the strengthening of people's environmental awareness, air quality has become the focus of the world Now people realize that air filtration system should not only protect mechanical equipment, but also protect people Therefore, the application of air filtration is more and more extensive The major application of air filtration is residential buildings, followed by commercial and industrial buildings In addition, filter equipment is often used in the following occasions: purification bench, clean room; copying equipment; indoor air purifier; anesthetic gas filter equipment; laser surgical application; HVAC system (heating, ventilation and air conditioning system); constant temperature room; computer printer; studio air filter system; air conditioner, etc 1 Due to the continuous improvement of people's requirements for the quality of life in the housing market, the original air filter system in the housing can no longer meet people's needs, and the electrostatic filter with higher performance has become a substitute for the original air filter However, compared with ordinary glass fiber filter, the application of electrostatic filter is limited due to the high cost of filter medium 3M is a leader in the electrostatic filter Market and is actively selling its products 3M company's electrostatic filter adopts corrugated structure, and the medium loading is loose, so the air flow resistance is small 3M says its filters are suitable in density and have a long life The corrugated structure can also improve the filtration efficiency and catch more particles than the flat filter In China, the vast majority of houses do not have air filtration system, but the number of houses in China is huge, and it increases by millions every year With the worsening of indoor air quality and the strengthening of people's environmental awareness, the application of air filtration system in residential buildings is promising, and there is a huge potential market 2 The driving force for the application of office buildings to improve the office air quality is the extensive application of advanced office equipment Computer terminals are the source of ozone and VOCs Inkjet printers are sources of hydrocarbons and ozone Hydrocarbon, respirable suspended particles and ozone are produced by dry process photocopier; ozone and volatile organic compounds are produced by fax machine; hydrocarbon, ozone and respirable particles are produced by laser printer; etc These products have seriously polluted the indoor environment and caused certain harm to people and office equipment It is estimated that 30% of office buildings and public buildings in the United States have indoor air pollution problems, especially the challenges faced by public buildings such as airports and stations are far greater than office buildings The air flow in the hall of d'hare airport in Chicago is about 51.66 million m3 / min in order to improve the air quality, there are 1100 prefilters, 1100 final filters and 2200 carbon filters (among which the carbon needs to be replaced every 10-12 months) It is estimated that the demand for air filter in office, commercial and public buildings will reach 500 million US dollars in the world in 2000 3 With the increasingly strict building standard of indoor air purifier, consumers pay more and more attention to indoor air quality Especially people with allergies, asthma or respiratory diseases, because air pollution affects their normal life People spend 90% of their time indoors, and the level of indoor air pollution may be 2-5 times that of outdoor Almost all indoor spaces contain pollen, mold, spores, animal hair, smoke, bacteria, viruses and harmful fibers and dust, including asbestos Poor air quality exacerbates asthma and allergies It is an effective method to remove indoor air pollutants with air purifier There are many products in the portable indoor air purifier market The fast-growing ones are electrostatic air filters using filter media, such as 3M's filtrete, and more micro glass fiber HEPA filters, which occupy the majority of the market In the United States, the air purifier market is increasing by more than 10% every year Japan is the second largest market after the United States In China, the demand for air purifier is also increasing With the continuous deterioration of air quality and the emergence of home office, air purifier will have a huge potential market 4 The air quality requirements of different factories vary greatly Factories equipped with smoke hoods and pollution control equipment need to supplement a large amount of air If the ambient air in the areas where these factories are located is polluted, the supplementary air must be filtered before being distributed to the workplace In semiconductor production and pharmaceutical industry, the requirement of air cleanliness is high In a typical work environment, there are 500000 particles per cubic foot of air, while the new requirement for semiconductor production is only one particle per cubic foot of air Therefore, clean air filtered by HEPA filter should be used to clean the workshop continuously In order to keep the clean and life of HEPA filter, several sections of prefilters with lower efficiency are needed Industrial cleanrooms require continuous and effective removal of smaller particles HEPA filter was once a high efficiency filter, now ULPA filter is a high efficiency filter, and a new generation of filter with higher efficiency will be developed and applied in the future Micro glass fiber filter media is the main choice of filter media, but the membrane and electrostatic reinforcement media have penetrated into the field and obtained some applications For the exhaust gas from the factory, the strict requirement is toxicity Some heavy metals, such as mercury, arsenic, chromium, beryllium and so on, are very toxic, and their emission limits are very strict In terms of air toxicity, the United States and Germany have passed new and stricter legislation After the implementation of the new legislation, the limit of air toxicity was reduced from the original 20mg / m3 (standard) to 010004mg / m3 (standard) To achieve this, factories need more advanced filters to remove submicron particles Some German companies use the traditional foldable micro glass fiber HEPA filter for filtration system, which cooperates with the pulse air cleaning mechanism and makes the ripple of filter medium more dense An American company has taken another step by designing tubular micro fiberglass HEPA filters 5 The hospital health industry is a very large and special industry, which also requires a high degree of air cleanliness In general, the low requirement of hospital air is to use a prefilter with an efficiency of 30% and a final filter with an efficiency of 90% HEPA filter filtration is generally not required, but is required in special cases such as isolation rooms, specific testing and care areas Many HVAC systems in hospitals use 100% outdoor air, which is a good strategy to prevent patients from cross infection through suspended microorganisms in HVAC system However, 100% use of outdoor air can not eliminate the growth of microorganisms in the air filter media and its adverse effects on the nursing environment Therefore, many hospitals still need advanced HVAC system The clean room of the health system is first used in the operating room At first, it was only widely used in orthopedic surgery, because orthopedic surgery took a long time and was easy to cause infection The ideal control level is to use the air cleanliness near the operating table to reach level 100 It is generally recommended to use top HEPA filtration system, which can cover an area of at least 3M × 3M, so as to include the operating table and people Other applications of clean room include delivery room, nursing room, burn room, patient care unit, etc One of the new developments is the application of clean room in dental surgery, which reduces the risk of infection in the long-term operation 6 Food processing and food industry is becoming an expanding market for air filtration equipment In order to keep the fresh taste of food, the method of disinfection to eliminate pollution has been gradually not used This makes the elimination of product related air pollution more important State regulations, insurance awareness and public concern are prompting Meat Processors, dairy producers and other food producers to update their air filtration systems In Europe, yogurt is canned in clean room conditions, the result is that the product can be preserved for a long time without adding expensive chemical preservatives Breweries found that in order to protect their draft beer, it is necessary to control the air pollution around the filling workshop Filling in the clean room is a good choice This kind of factory needs 100000 clean rooms, which can be filtered by HEPA filter with top ventilation system