depthfiltratie

Depth filtration is a physical separation process used to remove suspended solids from liquids or gases. Unlike surface filtration, where particles are caught on the surface of a filter medium, depth filtration involves trapping particles within the tortuous pathways of a porous filter material. This material is typically much thicker than surface filters and has a graded pore structure, meaning the pore size decreases from the inlet to the outlet.

The effectiveness of depth filtration relies on a combination of mechanisms. Inertial impaction occurs when larger particles cannot follow the fluid streamlines around the filter fibers and collide with them. Interception happens when particles, too small to be captured by impaction, come into contact with a filter fiber as they follow the fluid path. Adsorption is another important mechanism, where particles adhere to the filter media due to Van der Waals forces or electrostatic attractions. Sieving can also play a role, particularly in the finer layers of the filter, where particles larger than the available pore spaces are physically blocked.

Depth filters are widely used in various industries, including water treatment, pharmaceuticals, food and beverage processing, and chemical manufacturing. They are effective for removing a broad range of particle sizes and are often employed as pre-filters to protect finer filtration stages or as primary filters for less demanding applications. The choice of depth filter depends on factors such as the fluid characteristics, the size and concentration of contaminants, and the required level of purity.