Separation of solids from liquid is routinely encountered in industry. There is numerous needs for such differentiation, from iron and steel complex, oil and gas exploration and production, to manufacturing of cooking oil, separation of solids from liquid is indispensable.
Traditionally such separation is done by static setting – mixture of liquid and solids are sent to a container, or a specially designed tank with mechanism inside the tank with the intention to speed up the setting process.
The advantage of such static setting is low cost, as the tank and the associated transferring equipment is all what is needed.
The disadvantage is its low efficiency, as the deposition process is described by Stock’s law. The smaller the difference between the specific gravity of the two phases, the longer time it takes. Sometimes it takes so long that such process makes no sense.
In order to solve this problem, many efforts have been made. The decanter centrifuge by GN Solids Control is a very efficient solution.
Working under the principle of centrifugal force, the decanter centrifuge by GN Solids Control rotates the material inside the spinning bowl at the speed of up to 4500RPM. Generated G force can be up to 3000G. In other word it is 3000 times more efficient than static setting process, if G force is used as the comparison criteria.
Under such separation force, solids is quickly thrown to the surface of the bowl and liquid is floated on top of the set solids. A specially designed decanter inside the rotating bowl, a specially shaped screw conveyor, will send set solids to one side of the bowl and discharge solids through Tungsten Carbide enforced opening. Separated liquid will be discharged from the other end of bowl called weir whose height is adjustable.
A unique features of GN decanter is how the bowl is built. It is centrifugally casted with 2304 stainless steel, which results in pretty evenly distributed density throughout the bowl. This is crucial to the normal operation of the decanter centrifuge because of the very high G force. For instance, 1 gram of out of balance weight can be as big as 3000 gram at the highest rotation speed. Centrifugal casting greatly reduced the potential of out of balance, though it is much more expensive to cast the bowl.