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The rapid development of air filters is closely related to the development of military industry and electronic industry. In the first world war, the use of various chemical agents, asbestos fibre filter paper as the smoke filter layer of military gas masks came into being. The glass fiber filter medium is used in air filtration to obtain a patent in the United States in October 1940. In the 1950s, the United States studied the production process of glass fiber filter paper, and the air filter was improved and developed. In the 1960s, HEPA filters came out; In the 1970s, the filter paper of fine glass fiber was used as the HEPA filter of filter medium, and the filtration efficiency of particle size of 013 micron particle diameter was 99.9998%. Since the eighty s, with the emergence of new test method, use evaluation to improve and to improve the filtering performance requirements, found the HEPA filter there is a serious problem, and he had a higher ULPA filter performance. Countries are still working on it and expect more advanced air filters soon
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Homeowners are inundated with rising expenses and discovering the modern strategy to produce free electricity employing a magnetic power generator may be helpful in saving cash on heating expenses. It differs from a solar powered sort of generator. Unlike the solar, wind and ponds of generating energy, it's self-perpetuating and never dependent upon external forces.
Some of typical family fridge problems could possibly be predetermined yourself, you have to utilize a qualified to handle complex restoration perform. Even though the fridge may start looking span and spic externally, this doesn't suggest that the device is performing efficiently from the in. Incessant requests around the repairman and a lot of concerned times comply with, till you ultimately buy it fixed returning to its standard express. Did you realize there are specific methods for you to maintain family fridge operating smoothly? One can find in fact some strategies to repair the gear yourself, without counting on your normal assistance.
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