How Filtration Systems Efficiently Separate Liquids and Solids

As reported by Biology Online in their article Filtration,” filtration is a process where a heterogeneous mixture is passed over a filter medium with pores of a specific size, separating solids from liquids. Larger particles are retained on the filter, forming a filter cake, while the liquid (known as the filtrate) passes through. The mixture of solids and liquids that undergoes filtration is referred to as slurry.

A simple example of filtration is tea making, where tea leaves are separated from the liquid using a sieve. Similarly, air conditioners use filters to remove dust particles from the air. The basic parts of a filtration system include the filter medium, slurry, a driving force (such as pressure or gravity), and the filtration device holding the components in place.

The filter medium plays a crucial role and must be strong, resistant to the fluid’s properties, and efficient in allowing the passage of the liquid while retaining solids. Common filter media include woven cloths (made from wool, cotton, nylon, and other materials), perforated sheet metals, and porous solids like sintered glass or porous plastics. The choice of filter medium depends on the chemical makeup of the slurry and the intended outcome—whether to retain solids, collect liquids, or both.

The filtration process also depends on the driving force. Methods include:

  • Gravity: The simplest form, using the liquid’s weight to create pressure.
  • Low Pressure: A vacuum is applied below the filter, creating a pressure differential up to 1 bar.
  • High Pressure: Pressure is applied to the slurry’s surface, achieving higher differential pressures.
  • Centrifugal Force: Rapid spinning generates a force that aids in filtration by pushing the mixture outward.

Filtration efficiency depends on factors like the liquid’s viscosity, the solid particles’ size, and the overall proportion of solids in the slurry. Whether the goal is to wash the solids free of the liquid or to maximize liquid purity, careful selection of the filtration method is crucial.

Click here to learn more about Great Lakes Filtration products and solutions.

Article with all rights reserved, courtesy of biologyonline.com.

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