Dust control in the air is filtered by air filter, filter is the core equipment of air purification system. Three levels of air filtration are usually set in the purification system. The first level is at the fresh air outlet and the return air outlet, the second level is at the positive pressure section of the system, and the third stage is at the air supply end. There are many types of filters, according to the national standard clean room setting specifications are mainly divided into four categories: primary air filter, medium air filter, high efficiency air filter, super high efficiency air filter.
Primary air filter
The primary filter is the first level filter in the air conditioning and purification system. It can also be used alone as the air intake filter in the ordinary air conditioning system. All ventilation, air conditioning and purification systems with medium effect filters and high efficiency filters should be installed with coarse effect filters. The primary filter mainly filters dust with particle size of more than 5um and various foreign bodies. It is suitable for the primary filtration treatment of simple air conditioning purification system and ventilation system and the occasions with high dust concentration.
Medium effect filter
In the air conditioning system, the medium effect filter is commonly used in the back of the primary effect air filter to improve purification efficiency, and in front of the high efficiency filter to extend the service life of the high efficiency filter. The filter object of medium-effect filter is 1μm~5μm dust. The filter materials of medium effect filter mainly include polyester non-woven fabric, polypropylene non-woven fabric, medium cell foam plastic, fine cell foam plastic and medium effect glass fiber filter paper. The outer frame is made of special aluminum profile and galvanized plate frame. Medium effect filter has the characteristics of strong tension, small resistance, large air volume, large filtration area and so on. It is suitable for intermediate filtration of air conditioning and air conditioning purification and occasions with high dust concentration. The most used medium filter is bag type structure, long cleaning and replacement cycle.
High efficiency filter
High efficiency air filter is the last stage filter in the purification system. The filter object is mainly 0.3μm~1μm dust. For particles greater than or equal to 0.3um, the filtration efficiency is greater than or equal to 99.9%.
Super high efficiency air filter
Super high efficiency air filter refers to the air filter with the efficiency of the most easily penetrated particle size above 99.9995% and the initial resistance of the air flow below 250Pa under the rated air volume.
