Filtration is a physical separation process that separates solid matter and fluid from a mixture using a filter medium that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter medium are described as oversize and the fluid that passes through is called the filtrate. Oversize particles may form a filter cake on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter, known as blinding. The size of the largest particles that can successfully pass through a filter is called the effective pore size of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles. Filtration occurs both in nature and in engineered systems; there are biological, geological, and industrial forms. In everyday usage the verb "strain" is more often used; for example, using a colander to drain cooking water from cooked pasta.
A zaru is generally a flat or shallow basket made from bamboo used in the preparation and presentation of Japanese cuisine. It also has variations made of plastic or metal similar to a strainer, sieve or colander.
In cooking, a consommé is a type of clear soup made from richly flavoured stock or broth that has been clarified, a process that uses egg whites to remove fat and sediment.
A disc filter is a type of water filter used primarily in irrigation, similar to a screen filter, except that the filter cartridge is made of a number of plastic discs stacked on top of each other like a pile of poker chips. Each disc is covered with small grooves or bumps. The discs each have a hole in the middle, forming a hollow cylinder in the middle of the stack. The water passes through the small passages in between and the impurities are trapped behind.
A colander is a kitchen bowl-shaped utensil perforated with holes used to strain foods such as pasta or to rinse vegetables. The perforations of the colander allow liquid to drain through and discarded while retaining the solids inside. It is sometimes called a pasta strainer. A sieve, with much finer mesh, is also used for straining.
A deep fryer is a kitchen appliance used for deep frying. Deep frying is a method of cooking by submerging food into oil at high heat, typically between temperatures of 350 to 375 °F.
A particulate air filter is a device composed of fibrous, or porous materials which removes particulates such as smoke, dust, pollen, mold, viruses and bacteria from the air. Filters containing an adsorbent or catalyst such as charcoal (carbon) may also remove odors and gaseous pollutants such as volatile organic compounds or ozone. Air filters are used in applications where air quality is important, notably in building ventilation systems and in engines.
A chinois, also known as a bouillon strainer, is a conical sieve with an extremely fine mesh. It is used to strain custards, purees, soups, and sauces, producing a very smooth texture. It can also be used to dust food with a fine layer of powdered ingredient.
A tamis is a kitchen utensil, shaped somewhat like a snare drum, that acts as a strainer, grater, or food mill. A tamis has a cylindrical edge, made of metal or wood, that supports a disc of fine metal, nylon, or horsehair mesh. To use one, the cook places the tamis above a bowl and adds the ingredient to be strained in the centre of the mesh. The food is then pushed through using a scraper or pestle. Tamises have been in use since the Middle Ages.
A sieve analysis is a practice or procedure used in geology, civil engineering, and chemical engineering to assess the particle size distribution of a granular material by allowing the material to pass through a series of sieves of progressively smaller mesh size and weighing the amount of material that is stopped by each sieve as a fraction of the whole mass.
Mechanical screening, often just called screening, is the practice of taking granulated or crushed ore material and separating it into multiple grades by particle size.
A spider is a type of skimmer prevalent in East Asian cuisine in the form of a wide shallow wire-mesh basket with a long handle, used for removing hot food from a liquid or skimming foam off when making broths. The name is derived from the wire pattern, which looks like a spider's web. It has been widely adopted in Western cuisine by cooks who favour the open mesh over slotted spoons for faster and safer drainage.
A sieve is a tool to separate materials of one characteristic from materials of another.
Maize miller is the processing of maize (corn) for safe and palatable consumption as food. Processing can be by machine-milling in either large- or small-scale mills, or by hand-milling in domestic or community settings.
Duplex strainer or twin basket strainer is a type of filter built into a fuel, oil or water piping system and it is used to remove large particles of dirt and debris. The duplex strainer system usually consists of two separate strainer baskets housings. The system also contains a valve handle placed between the two baskets to divert the flow of liquid to one strainer while the other is being cleaned. On some strainers, the valve will work automatically and the strainer will perform a self-cleaning operation.
Tumbler screening is a separation method that uses three-dimensional elliptical movement to separate very fine particles from larger ones.
The peeler centrifuge is a device that performs by rotating filtration basket in an axis. A centrifuge follows on the principle of centrifugal force to separate solids from liquids by density difference. High rotation speed provides high centrifugal force that allows the suspended solid in feed to settle on the inner surface of basket. There are three kinds of centrifuge, horizontal, vertical peeler centrifuge and siphon peeler centrifuge. These classes of instrument apply to various areas such as fertilisers, pharmaceutical, plastics and food including artificial sweetener and modified starch.
A trommel screen, also known as a rotary screen, is a mechanical screening machine used to separate materials, mainly in the mineral and solid-waste processing industries. It consists of a perforated cylindrical drum that is normally elevated at an angle at the feed end. Physical size separation is achieved as the feed material spirals down the rotating drum, where the undersized material smaller than the screen apertures passes through the screen, while the oversized material exits at the other end of the drum.
Gyratory equipment, used in mechanical screening and sieving is based on a circular motion of the machine. Unlike other methods, gyratory screen operates in a gentler manner and is more suited to handle fragile things, enabling it to produce finer products. This method is applicable for both wet and dry screening.
Screen/Scroll centrifuge is a filtering or screen centrifuge which is also known as worm screen or conveyor discharge centrifuge. This centrifuge was first introduced in the midst of 19th century. After developing new technologies over the decades, it is now one of the widely used processes in many industries for the separation of crystalline, granular or fibrous materials from a solid-liquid mixture. Also, this process is considered to dry the solid material. This process has been some of the most frequently seen within, especially, coal preparation industry. Moreover, it can be found in other industries such as chemical, environmental, food and other mining fields.
