Liquid filters are equipment used to separate suspended solids from a fluid stream. A physical barrier, called the filter medium, is a prerequisite in the filtration process in which the liquid passes through and where the solids are retained. They are widely used in many solid-liquid mechanical separation processes. They differ from centrifuges, clarifiers, and gravity settlers which do not utilize such media.
Liquid filters are usually found in food and beverage manufacturing, bioprocessing, semiconductor and electronic components manufacturing, pharmaceutical industries, medical facilities, and wastewater treatment. Small-scale filters such as bag filters and cartridge filters are found in some homes, offices, and laboratories.
Liquid filters may be used as pre-treatment equipment to a downstream process, wherein removal of solids is crucial in achieving product quality and safety, and in maintaining the efficiency of the downstream equipment. Filtration of solids is important in upholding the performance of a pipeline and pumping systems. It is also critical in manufacturing products intended for human consumption, such as beverages and drinking water.
Filtration is also applicable to solid-gas separation and works in a similar concept, but this article mainly focuses on liquid-solid separation.