|
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
|
During our childhood, we've read a lot about flying chariots in may divine stories. Though we did not accept it, we currently see people traveling by airplanes. Traveling is becoming really easy nowadays. The automobile industry has additionally undergone a great deal of changes since invention of steam engine vehicle. How many of you know the Benz patent motor car of 1885 would be a motorized tricycle? Today find millions of automobiles on the highway, in several models, shapes, sizes, colors, and prices.
Algae really are a broad gang of simple plants which range from single-celled diatoms to fifty meter long giant kelp. There are over 100,000 species. Some algae form symbiotic relationships to organisms to construct lichens and coral reefs. Among the oldest organisms on Earth, algae found in the Vindhya Basin of India go as far back over 1.5 billion years.
New Car Buying Tips--
new york state lemon law used cars
new hybrid cars for sale
new fuel efficient cars
what is a good deal on a new car
new nitro rc cars
Copyright ?1998-2017 Technews Corp, All rights reserved
|
