What is a Centrifuge?
A centrifuge is a device which generates a centrifugal force and separates solids from liquid, or separates two kinds of liquids which are not dissolved into each other (like water and oil) and whose specific gravities are different.
When turbid water is put in a bucket and left for a while, clear upper water is separated from solids, such as sand. This is the state in which objects whose specific gravities are different have been separated due to gravity.
When you hold the bucket in one hand and revolve it, a centrifugal force acts on the turbid water and the separation rate increases.
Centrifugal filtration is equivalent to draining out just the water, from small holes made on the bottom of the bucket.
A machine in which this action is forcibly produced is a centrifuge.
Mechanism of a centrifuge
A rotating body (basket) is fitted inside the machine. A centrifugal force is obtained by spinning the rotating body at high speed.
A filter medium (cloth, metal filter) is attached to the rotating body. The substance being processed is separated into solids and liquid because the liquid can pass through the filter medium.
For separation by specific gravity difference, such as separation of liquid and liquid, or liquid and fine solids, the rotating body does not have a filter and holes for the liquids to pass through. A heavy liquid is separated onto the wall of the rotating body, and a light liquid is layered onto the heavy liquid. Each of the liquids is drained to recover separate liquids.
Separation of solids and liquid is "Solid-liquid separation", and separation of liquids is "Liquid-liquid separation".
Types of Centrifuge
Centrifugal filter and centrifugal settling machine
There are two types: a centrifugal filter and a centrifugal settling machine.
The centrifugal filter uses a filter medium. Liquid in the substance being processed passes through the filter medium and solids and liquid are separated.
The centrifugal settling machine does not use a filter medium. The machine separates the substance being processed with using a skimming device by draining the clean water of the liquid and solids which were separated by specific gravity difference.
Batch type and continuous type
"Batch type" is a system where all the processes from fluid supply, separation, and cleaning to discharge are completed batch by batch.
"Continuous type" is a system where a series of the process in which fluid is supplied and discharged, is carried out continuously.
> Batch type KM DMN BDMN DIBUC MARKⅢ eMV JMP-V JMP-S HERVA LAC
> Continuous type M Series
- Vertical type and horizontal type
There are vertical-type and horizontal-type centrifuges, as with washing machines, depending on the orientation of the basket.
> Vertical type KM DMN BDMN DIBUC MARKⅢ HERVA LAC typeM> horizontal type eMV JMP-V JMP-S
Deoiled milling chips are discharged continuously by continuously charging milling chips into a ball-type basket.
> M Series
Inclined discharge type
Substances are discharged from an inclined opening of the centrifuge.
Uses of centrifuges
Centrifuges are used for manufacturing pharmaceutical products, chemical products, agricultural chemicals, electronic material and food.
Centrifuges are used in various other kinds of field, such as treatment of industrial waste and sludge, purification and recycling oil recovered from milling chips. Centrifuges are installed in hospitals, laboratories in colleges and companies.
Calculation of centrifugal force
Basic calculating formula
RCF=1119 X r X N2 X 10-8
RCF: Centrifugal acceleration (X g) r: rotational radius (cm) N: Number of revolutions per minute (rpm)
The relative centrifugal force (X g) can be calculated easily using the conversion system.
The circular constant is 3.14159 in the calculation.