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A separator is a centrifugal device that separates milk into cream and skimmed milk. [1] [2] Separation was commonly performed on farms in the past. Most farmers milked a few cows, usually by hand, and separated milk. Some of the skimmed milk was consumed while the rest was used to feed calves and pigs. Enough cream was saved to make butter, and the excess was sold.
Today, milk is separated in industrial dairies. Sufficient cream is returned to the skimmed milk before sale.
Before the advent of centrifugal separators, separation was performed by letting milk sit in a container until the cream floated to the top and could be skimmed off by hand. A variant container-separator had a nozzle at the bottom which was opened to allow the milk to drain off. A window in the side, near the nozzle at the bottom, allowed the operator to observe when the milk was drained.
The centrifugal separator was first manufactured by Gustaf de Laval, making it possible to separate cream from milk faster and more easily, without having to let the milk sit for a time, and risk it turning sour. Possibly because Gustaf de Laval manufactured the first cream separators, [3] [4] many people credit the invention to de Laval. However, many patents appear before his, all of them labelled as 'improvements'. One of the first specifically for cream separation was patented by W. C. L. Lefeldt and C. G. O. Lentsch. [5]
The original centrifugal separators were hand-cranked, as illustrated.
Manual rotation of the separator handle turns a worm gear mechanism which causes the separator bowl to spin.
When the separator is spun, the heavier milk is pulled outward against its walls and the cream, which is lighter, collects in the middle. The cream and milk then flow out separate spouts. After separation, the cream and skimmed milk are mixed together in a certain ratio until the favoured fat content has been set. The ratio is dependent upon the product which is to be produced (low-fat milk, full-fat milk or cream). Some floor model separators were built with a swinging platform attached to the stand. The bucket for collecting the cream was put on the platform, and a much larger bucket was set on the floor to collect the milk. Some floor model separators had two swinging platforms. Smaller versions of separators were called table-top models, for small dairies with only a few cows or goats.
Gustaf de Laval's construction made it possible to start the largest separator factory in the world, Alfa Laval AB. [6] The milk separator represented a significant industrial breakthrough in Sweden. Within the first decade of the 1900s, there were over twenty separator manufacturers in Stockholm. Separators in modified form are also used on ships to purify oil, which may have been their original use, because in its original form de Laval proposed the separator for use in his steam turbine. De Laval's turbine used mechanically lubricated journal bearings which were not insulated from the inside of the turbine. When the steam condensed into water it contaminated the oil. To purify the oil a centrifugal separator was used, which was later adapted to the dairy industry.
The original design had a manual bowl that required manual cleaning. Most modern separators use a self-ejecting centrifuge bowl that can automatically discharge any sedimentary solids that may be present, thus allowing clean-in-place (CIP).
A distinction is made between warm milk skimming and cold milk skimming: [7]
Cream is a dairy product composed of the higher-fat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, eventually rises to the top. In the industrial production of cream, this process is accelerated by using centrifuges called "separators". In many countries, it is sold in several grades depending on the total butterfat content. It can be dried to a powder for shipment to distant markets, and contains high levels of saturated fat.
Dairy products or milk products, also known as lacticinia, are food products made from milk. The most common dairy animals are cow, water buffalo, nanny goat, and ewe. Dairy products include common grocery store food around the world such as yogurt, cheese, milk and butter. A facility that produces dairy products is a dairy. Dairy products are consumed worldwide to varying degrees. Some people avoid some or all dairy products because of lactose intolerance, veganism, environmental concerns, other health reasons or beliefs.
Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest solid food. Milk contains many nutrients, including calcium and protein, as well as lactose and saturated fat. Immune factors and immune-modulating components in milk contribute to milk immunity. Early-lactation milk, which is called colostrum, contains antibodies and immune-modulating components that strengthen the immune system against many diseases. The US CDC agency recommends that children over the age of 12 months should have two servings of dairy (milk) products a day, and more than six billion people worldwide consume milk and milk products.
Butter is a dairy product made from the fat and protein components of churned cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condiment, and used as a fat in baking, sauce-making, pan frying, and other cooking procedures.
A centrifuge is a device that uses centrifugal force to subject a specimen to a specified constant force, for example to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby separating fluids of different densities or liquids from solids. It works by causing denser substances and particles to move outward in the radial direction. At the same time, objects that are less dense are displaced and moved to the centre. In a laboratory centrifuge that uses sample tubes, the radial acceleration causes denser particles to settle to the bottom of the tube, while low-density substances rise to the top. A centrifuge can be a very effective filter that separates contaminants from the main body of fluid.
Clotted cream is a thick cream made by heating full-cream cow's milk using steam or a water bath and then leaving it in shallow pans to cool slowly. During this time, the cream content rises to the surface and forms "clots" or "clouts", hence the name. Clotted cream is an essential ingredient for cream tea.
A de Laval nozzle is a tube which is pinched in the middle, making a carefully balanced, asymmetric hourglass shape. It is used to accelerate a compressible fluid to supersonic speeds in the axial (thrust) direction, by converting the thermal energy of the flow into kinetic energy. De Laval nozzles are widely used in some types of steam turbines and rocket engine nozzles. It also sees use in supersonic jet engines.
Karl Gustaf Patrik de Laval was a Swedish engineer and inventor who made important contributions to the design of steam turbines and centrifugal separation machinery for dairy.
Alfa Laval AB is a Swedish company, founded in 1883 by Gustaf de Laval and Oscar Lamm. The company started by providing centrifuges to dairies to be used to separate cream from milk. It now deals in the production of specialised products for heavy industry. The products are used to heat, cool, separate and transport such products as oil, water, chemicals, beverages, foodstuffs, starch and pharmaceuticals.
Separator can refer to:
Tumba is a bimunicipal locality and the seat of Botkyrka Municipality in Stockholm County, Sweden with 37,852 inhabitants in 2010. A part of its statistical urban area, called Rönninge, is in Salem Municipality. The population is 35,311 (2005). The Swedish krona banknotes are printed by Crane AB at Tumba Bruk, in Tumba. Tumba is situated half-way between Stockholm and Södertälje and is considered a Stockholm suburb. In Tumba and Rönninge there are stations on the Stockholm commuter rail network.
Skyr is a traditional Icelandic cultured dairy product. It has the consistency of strained yogurt, but a milder flavor. Skyr can be classified as a fresh sour milk cheese, similar to curd cheese consumed like a yogurt in the Baltic states, the Low Countries and Germany. It has been a part of Icelandic cuisine for centuries.
Churning is the process of shaking up cream or whole milk to make butter, usually using a device called butter churn. In Europe from the Middle Ages until the Industrial Revolution, a churn was usually as simple as a barrel with a plunger in it, moved by hand. These have mostly been replaced by mechanical churns.
A creamery or cheese factory is a place where milk and cream are processed and where butter and cheese is produced. Cream is separated from whole milk; pasteurization is done to the skimmed milk and cream separately. Whole milk for sale has had some cream returned to the skimmed milk.
Tetra Pak is a Swedish multinational food packaging and processing company headquartered in Switzerland. The company offers packaging, filling machines and processing for dairy, beverages, cheese, ice cream and prepared food, including distribution tools like accumulators, cap applicators, conveyors, crate packers, film wrappers, line controllers and straw applicators.
DeLaval is a producer of dairy and farming machinery, with a head office in Tumba, Sweden, and is part of the Tetra Laval group. The company has 18 factories worldwide, employs over 4,500 people.
Dairy machinery encompasses and describes a wide range of machine types that are involved in the production and processing of dairy related products such as yogurt, ice cream, processed cheese, desserts and is a slightly different genre to pure milking machinery.
The fat content of milk is the proportion of milk, by weight, made up by butterfat. The fat content, particularly of cow's milk, is modified to make a variety of products. The fat content of milk is usually stated on the container, and the color of the label or milk bottle top varied to enable quick recognition.
The Gerber method is a primary and historic chemical test to determine the fat content of substances, most commonly milk and cream. The Gerber method is the primary testing method in Europe and much of the world. The fairly similar Babcock test is used primarily in the United States, although the Gerber method also enjoys significant use in the U.S. as well.
A conical plate centrifuge is a type of centrifuge that has a series of conical discs which provides a parallel configuration of centrifugation spaces.
Media related to Cream separators at Wikimedia Commons