The rapid development of air filters is closely related to the development of military and electronic industries. Glass fiber filtration media for air filtration was patented in the United States in October 1940. The 50 's, the United States of glass fiber filter paper in the production process of in-depth research, so that the air filter has been improved and developed. In the 60 's, the HEPA filter was published, and in the 70 's, the HEPA filter with fine glass fiber filter paper was used as the filter medium, and the particle filtration efficiency of 013 micron particle size was as high as 99.9998%. Since the 80 's, with the emergence of new test methods, the improvement of the use evaluation and the improvement of filtration performance, it is found that there are serious problems in HEPA filter, and the ULPA filter with higher performance is produced. At present, countries are still working hard, and it is estimated that more advanced air filters will soon emerge.
One of the most important is the removal of the separator plate, that is, the development of filter without clapboard. The barrier-free filter Not only eliminates the danger of damage to the filter media, but also effectively increases the filtration area, enhances the filtration efficiency and reduces the airflow resistance, thus reducing the energy consumption. In addition, the air filter in high temperature, corrosion resistance and waterproof, bacteria and other aspects also take a lot of progress, to meet a number of special needs.