FINE DUST
The air that surrounds us is composed of a variable mixture of different gases, in which solid particles are also dispersed. Their diameter varies in a range between 0.1 and 100 µm and they can be classified as substances of mineral, vegetable, animal matrix or as microorganisms. This category also includes the famous "pollution" particles that we often hear about: PM10, PM2.5, PM1 ... The fine dust filters act as a barrier to all these particles
Fine dust filters: how they work
The fine dust filters used in an air conditioning system intercept the particles present in the air flow. The efficiency of the filter is the result of many factors, including the particle size and their concentration in the air flow, while the dust retention capacity depends mainly on its geometry and size
The filter element must be replaced when it reaches its saturation; this occurs when the accumulated particles increase the pressure drop of the filter beyond the maximum values recommended for its replacement indicated on the technical data sheets. Generally, for replacement, a final value of the pressure drop equal to 3-4 times the initial value is considered
Fine dust filters: types
Fine dust filters can be rigid bag filters, soft bag filters or panel filters:
- Rigid bag filters: they are characterized by a series of panels arranged in a V configuration to have a high filtering surface. The media is made of pleated microfiber glass paper. Rigid bag filters are available in 3 versions which differ in the number of panels. The 4RT rigid bag filter has a 4V configuration with 8 pleated paper panels and a filtering surface of 18 m2 (for the 592x592 size). The 3RT Series Rigid Bag Filter is configured with a 3V design and 6 paper panels. The reduction of the filtering area (from 18 to 14 m2) is compensated by the lower aeraulic impact of the frame which, being more "open" than the 4RT series, guarantees the same initial pressure drops for the same flow rate. The 2RT series of rigid bags is instead designed for a system start-up use and thanks to its 2V configuration with 4 panels (10 m2 of filtering surface) it is particularly economical but with limited performance in terms of both duration and aeraulic performance.
- Soft bag filters: a series of synthetic fiber or fiberglass bags are mounted inside the frame. The filtering surface is limited compared to rigid bag filters and the depth of the filter is variable.
- Panel filters: compact in size, they are made with a pleated glass microfibre paper panel. The filtering surface is very small.