Dry air filter is a filter which separates impurities from air through a dry filter element, such as paper filter element.
Air filters used for light vehicles (including cars and mini cars) are generally single stage.
Its shape is flat or elliptical and flat. Filter material is filter paper or nonwovens. The end cover of the filter element is metal or polyurethane, and the shell material is metal or plastic. Under rated air volume flow, the original filtration efficiency of the filter element should be no less than 99.5%. Due to the bad working environment, the heavy duty air filter must have a large number of air filters.
The first stage is a swirling filter (such as blade ring, swirl pipe, etc.), which is used to filter the coarse particle impurities, the filtration efficiency is above 80%, and the second stage fine filter is microporous paper filter core (generally called the main filter core), and its filtration efficiency is over 99.5%. There is also a safety filter element after the main filter, which is used to prevent dust from entering the engine when the main filter element is installed and replaced or when the main filter element is accidentally damaged.
The material of the safety core is mostly nonwovens and filter paper.