Filtration

Filtration is a mechanical means of separating solids from a liquid suspension via a porous medium or screen that permits the liquid to pass while retaining the solids. Similar to conventional filtration, achieved via a differential pressure across a filter, centrifugal filtration is driven by the pressure exerted by a liquid medium within a centrifugal force field. Opposing the centrifugal pressure is the combined resistance of the porous medium and filter cake. Centrifugal filters are commonly used to remove or recover coarse and crystalline solids from a fluid slurry, often followed by a rinse cycle to purify the solids and remove the residual mother liquor. In this technique, a sample slurry is fed to the rotor with the centrifugal pressure forcing the carrier liquid through a cylindrical screen or other permeable medium positioned around the outer wall to retain the solids or filter cake. The filter cake may be dried by shutting off the slurry feed and spinning the solids to attain resid ual moisture contents lower than generally provided by filter presses or vacuum filters. Most centrifugal filtration applications are typically conducted in continuous or semi-batch mode in which the liquids passing the filter are continuously discharged and the filter cake is continuously discharged or recovered post run. Perhaps the most widely used example of centrifugal filtration is the spin cycle in domestic washing machines.

Centrifugal filtration is a complex process that is dependent on a number of parameters including liquid viscosity, cake thickness, centrifugal force, screen area and, importantly, the size and packing characteristics of the particles themselves. Centrifugal filtration may be conducted in batch, semi-batch or continuous mode. While traditional industrial applications commonly use centrifugal filtration to recover solid materials with reduced moisture contents, many laboratory-scale spin filters, particularly in a test-tube configuration, are available. This technique is generally not amenable to broad generalizations and is, therefore, best approached on a case-by-case basis.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

Get My Free Ebook


Post a comment