Filter stages are indispensable in ventilation equipment. They protect the equipment from external agents that may affect it or are used to prevent contaminants from entering through the ventilation ducts in places that must be sterile (operating theatres, clean rooms, etc.). Let's take a look at the types, the rules that govern them and their usual application.
As they are components that are in contact with contamination and dirt, it is very important that these filters are properly maintained. Thereby, it's ensured their optimal functioning and, above all, that they are replaced at the times specified by the manufacturer or the device alarm.
But what is a filter? A filter is a component designed to reduce the concentration of solid particles in the air. There are different filter stages, which are generally: metal mesh, filter bags, filter media, plant or activated carbon filters, HEPA filter and HEPA or ULPA terminal filter (depending on the application). Air filters must take two factors into account to be effective:
Filtration capacity
Pre-filters: they are those stages that are included in the suction phase of the device and prevent the entry of larger objects such as leaves, insects, small rodents, or other large contaminants into the system.
Particles size | Examples | Filter class | Typical applications |
Coarse dust, particle size > 10 µm |
| G4 |
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At Airtècnics we have the Metallic Z-Line filter. It is a metallic filtering stage made of galvanized sheet metal with zig-zag synthetic fibre media. According to EN 779 standard it is classified as G4 and the ASHRAE efficiency is 95%. And it can be included in most ventilation and air purification equipment such as any model of K7, Cyclohnic, Kleenbox or Dif-Pur.
Particles size | Examples | Filter class | Typical applications |
Fine powders, particle size 1 - 10 µm |
| F5 |
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F5 F6 F7 |
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| F7 F8 F9 |
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This category includes Diedrik and Multibag filters from Airtècnics catalogue.
Particles size | Examples | Filter class | Typical applications |
Suspended particles, particle size < 1 µm |
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| H 14 |
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At Airtècnics we also have the absolute filters: