HEPA filter
A HEPA filter is a type of air filter. Its name is an acronym from the English high efficiency particulate arrestance, i.e. a highly efficient filter of air particles. This type of air filter is able to remove particles with a size of 300 nanometers (particles of this size are the most difficult for HEPA filters to filter) with at least 99.97% efficiency. Larger particles are filtered with even greater efficiency.
In addition to nuclear energy, HEPA filters are used in healthcare, pharmaceuticals and research, or in the production of microprocessors.
A HEPA filter is generally the most advanced filter for filtering air. That is why it is often used in households and in vacuum cleaners, if the vacuuming is to be really effective in terms of cleanliness, especially for allergy sufferers. It is usually included as the last (output) filter.
The HEPA filter was originally developed by NASA to protect people from radioactive contamination. Efficiency of HEPA filter no. 13 (no. 13 all higher-quality vacuum cleaners have) when filtering the air is 99.97%, or if out of every 10,000 particles with a size above 0.01 micrometer, only 3 particles pass through. Hepa filter number, so-called the class can be 10 to 17, while the most common in good vacuum cleaners are classes 12 and 13. Washable HEPA filters (e.g. in bagless vacuum cleaners) or filters in cheaper vacuum cleaners are also class 11.
Modern dust bags made of non-woven fabric (e.g. SMS material) have filtering capabilities at the level of HEPA filter no. 10.
You can recognize the HEPA filter at first sight. It definitely does not look like a foam or felt or paper filter. It has several layers, while the size of the surface through which the air flows, the so-called, is important. absorption surface. By folding it into an accordion, a large absorption surface is achieved in a small space.
The HEPA filter in the vacuum cleaner can thus have 1,800 cm² of absorption surface folded into a small space. And this folding is characteristic of HEPA filters.