Centrifuges have been used in dairies and cheese making plants for more than 100 years. A large number of different types of centrifuges are employed.
The most common dairy centrifuge is the cream separator or skimming separator. These are used in a variety of stages in the process, described as examples below:
Cream separator (milk separator) for milk skimming
The classic application was, and still is even today, the separation of milk into cream and skimmed milk. The cream separator (milk separator) does not only separate the cream from the skimmed milk but also centrifuge off any impurities that might be contained in the raw milk. The skimmed milk is subsequently e.g. mixed with cream again to achieve the desired fat content in the milk, or is further processed (e.g. to produce cheese). The cream is generally used for the production of butter.
Separators for whey skimming
The whey produced during the manufacture of cheese still contains fat. This fat is valuable and can be recovered using a special whey skimming separator. For this reason, the whey is generally also skimmed.
Furthermore, there are also cleaning separators in various versions to suit the application. These differ from the skimming separators in that they separate only solids. These cleaning separators are employed today predominantly for the following applications:
Clarifiers for whey clarification
Before the whey can enter the skimming separator for skimming, it has to be precleaned. This precleaning can be performed e.g. with screens, but is most effective if again a cleaning separator designed specially for this application is employed. Use of this type of cleaning separator also increases the efficiency of the downline whey skimming separator.
Clarifiers for milk clarification
Cleaning separators designed specially for the application are also employed to remove any impurities from the raw milk.
Cleaning of CIP lyes
The CIP lyes employed in the dairy have to be replaced very quickly without treatment. The resulting costs for lye disposal and the mixing of new lye are considerable. In order to extend the service life of these CIP lyes, special cleaning separators can again be employed that clean the lyes very efficiently in a very short time.
In order to prolong the shelf life of consumers milk or to prevent undesirable reactions during cheese production, sterilising separators or "bactofuges" are employed.
Bactofuges / Bacteria removing separators
Bacteria removing centrifuge or bactofuge can be employed for consumers milk and cheese milk, but also for skimmed milk (or whey) and special processes.
Apart from milk and whey , other products are also manufactured in the dairies and cheese making plants such as e.g. cottage cheese (quark), cream cheese, double cream cheese, butteroil, casein and lactose (milk sugar). Special centrifuges are employed for the manufacture of these products and are described briefly below:
Production of quark using quark separators
The quark separator, a separator designed specially for this application, is charged here with thickened skimmed milk. The concentrated quark is discharged continuously. Modern quark separators can also be cleaned in place ("CIP").
Production of cream cheese
Special separators that can also be cleaned in place ("CIP") are employed for the production of cream cheese. Here the separator is charged with thickened fatty milk instead of skimmed milk.
Production of double cream cheese
Special separators are also employed for the production of double cream cheese.
Production of butteroil
The production of butteroil using special separators is normally a two-stage process. Thanks to its good shelf life, butteroil is particularly suitable for use in tropical regions, but it is also used for baking, cooking and frying.
Apart from separators, decanters are also used in the dairy industry. A few typical fields of application are described below:
Production of casein
The precipitated casein is separated out of the resulting whey in a special casein decanter. Casein has a wide range of applications; both in the foodstuffs industry and for technical purposes.
Production of lactose (milk sugar)
The lactose is precipitated and subsequently separated in a special decanter. Lactose (milk sugar) is employed i.a. as a basis for tablet compounds, and also as a coating, binding and filling agent.
Concentration of cheese fines
The cheese fines/whey/water mixture discharged by the automatic emptying when using whey clarification and/or whey skimming separators can be further processed to a concentrated, valuable cheese mass. Special decanters can be employed here that can significantly increase the solid non-fat content of the mixture described above.