Air filter secondary pollution and preventive measures
Microorganisms deposited on air filters can cause serious secondary pollution if they are not treated promptly. At present, to prevent the pollution of primary filters, basically are the use of auxiliary measures, among which the ultraviolet lamp is the most widely used, but also the most mature, the most effective measure. But the ultraviolet ray also has its disadvantage: the service life problem (the service life of domestic tube is only 2000 hours, the service life of import tube is 4000 hours) all affect the extensive use of ultraviolet lamp. Recently, low-temperature plasma also began to be used together with air filters in air conditioning systems, but the actual effect has yet to be verified by engineering. Currently, the high price seriously affects the promotion of this advanced technology in air conditioning systems. Therefore, to find out the measures to prevent the secondary pollution of air filters and to kill the harmful microorganisms deposited on the filters is a subject worthy of further study.
Electret electrostatic synthetic fiber filter material is used to make polypropylene fiber into electrostatic electret melt-blown nonwovens (filter paper) during the process of melt-blown manufacturing. The diameter of the fiber is 2 ~ 5 m. In addition to the filtration mechanism of traditional air filtration materials, this filter material also USES the coulomb force of the charged fiber to capture the particles, thus increasing the efficiency and decreasing the resistance. This filter material is used in the current international surgical masks (N95, N97, N99) for virus prevention, as well as in the anti-sars air filters introduced in the United States in April 2003.
Because of this early effect filter filter material, high efficiency, low resistance, the price is cheap, therefore, the author first use this material for general air-conditioning and ventilation air filter, when the windward side wind speed 0.5 m/s, to 0.5 mu m the dust in the filtration efficiency can reach more than 95%, only 40 pa, air resistance is one of the traditional cabinet air conditioning unit air filter (generally for nylon net) cannot be compared. This kind of air filter has been used in large shopping malls, supermarkets and hospital air-conditioning systems for nearly 10 years, and has achieved good air purification effect.
The production process has been comprehensively improved to produce electret electrostatic filter material with sodium flame method efficiency up to 99.9999%, which also solves the disadvantages of poor uniformity and low strength of this filter material, providing an ideal filter material for hepa filters. The production of electret electrostatic synthetic fiber filter material has largely solved the contradiction between the efficiency of air filter and the resistance.