and common usage, a filter
is a device (usually a membrane or layer) that is designed to block certain objects or substances while letting others through. Filters are often used to remove harmful substances from air
, for example to remove air pollution
, to make water drinkable, to prepare coffee
. In domestic food and drink preparation where bulk solids are removed from liquids, this is often called a strainer
Filtrate is the liquid produced after filtering a suspension of a solid in a liquid.
Filtrand (or Residue) is the solid residue remaining in the filter following filtration.
For certain situations, such as separating an aqueous substance from a solid one, filtering may be replaced with decanting.
Filters for various substances:
Filters for specific applications:
Filters by various methods:
Related devices and concepts: