Mechanical Separation
Fabric Filters
Fabric filters are used in order to safely and economically clean air containing a high concentration of dust.
For a fabric filter to be used, there needs to be a relative air humidity of 90%, and the dust to be removed should be as dry as possible. In the field, fabric filters are generally constructed as dust collectors.
How it works: The air is channeled from the outside to the inside. On the surface of the filter medium, particles are separated out throug the barrier effect. A dust cake builds up, contributing an added separation effect.
Depth Filters
Filtering separators such as depth filters are able to filter out very fine particles (as fine as < 0.1 microns). They usually consist of high-porosity random-laid fabric. Solid contaminants are filtered out of the air stream through fine networks of thin fibers. As they flow through the fiber layer, particles must first land on a fiber and then stick to it.
The main mechanisms are:
- Inertia (effective for particles > 1 micron)
- The barrier effect (especially effective for particles of 0.3 - 1 micron) and
- Diffusion (Brownian molecular movement, effective for particles < 0.3 micron.)
Adsorption
The word “adsorption” comes from Latin and means "to gather (gas) on the surface of solid bodies in a condensed layer." Methods such as the following can be used to reduce toxic gas concentrations:
- Reducing concentrations by adding air
- Activated charcoal
- Granulates with catalyzers
- Gas scrubbers
- Biofilters
- Catalytic combustion
Funktionsprinzip der Prallabscheidung
Prallabscheider machen sich den Trägheits-Effekt zunutze.
Metallfilterzellen: Bei ihnen werden die Partikel entsprechend dem im Trägheits-Effekt beschriebenen Abläufen abgeschieden. Staubpartikel werden eingespeichert, flüssige Aerosole fließen ab.
