Filtration. Mechanical operation , which by the action of a filter medium and a pressure gradient, the separation of a solid from a fluid is obtained. The suspension circulates through the equipment, in which the solids present in the flow are deposited, forming a bed of particles, through which the suspension to be filtered must continue to circulate.
Summary
[ hide ]
- 1 Filtration Mechanisms
- 1 Types of Filters
- 2 Most common factors that affect the filtering speed
- 2 Applications
- 3 Sources
Filtration Mechanisms
- Deep bed filtration. The solids are deposited inside the filter medium.
- Filtration with cake formation (conventional). The solids are deposited on the filter medium forming a paste.
- Membranefiltration . There is no solid deposit on the membrane, but a concentration of the broth. The membrane mainly filters on the surface of the membrane. Particles larger than nominal porosity remain on the filter, while smaller particles pass the filter.
Filter Types
According to these filtration mechanisms, the following types of filters are available.
The choice of the most suitable type of filter depends on many different factors: on the species, quantity and size of the particles to be separated, on the species, volume and temperature of the medium to be filtered, as well as on the filtration method and the required precision.
Examples of filter media are: fabrics , fiber fabrics, felt or non-woven fibers, porous or perforated solids, polymeric membranes or particulate solids in the form of a permeable bed.
Most common factors that affect the filtering speed
- The pressure drop from the feed to the far side of the filter media.
- The area of the filtering surface.
- The viscosity of the filtrate.
- Filter cake resistance.
- The resistance of the filter medium and the initial layers of the cake.
Applications
Filtration has a wide range of applications, from the analytical procedure in the laboratory to technical applications on large production lines. It is filtered in practically all branches of industry – for example, in food analysis, mortar testing, smoke analysis or microbiological control .
With the aid of filtration, solid components of suspensions or gases can be separated , as well as liquid components of aerosols or emulsions. Using a hydrophobic filter, water can be filtered from fuels. Air or other gases can be cleaned from water, oil or tar sprays .
