In ancient China, people tie the stean with one side of rope, and put the other side in hand, to revolve the stean, so form the centrifugal force, that could extrude the honey from the stean. That is the earlier use of centrifugal separation priciple.
    The industrial centrifuges were born in Europe, such as the middle of 19th century, there appeared the tri-column centrifuges that used for the dehydration of textile, and the top suspension centrifuges that used for separating granulated sugar. These earlier centrifuges are all discontinuous operating and manual discharging. Because of the improvement of the discharging device, in 1930s, there appeared continuous operating centrifuges, and the discontinuous operating centrifuge also improved with the active manipulation.
     According to the constitution and different requirements, the industrial centrifuges can be divided into filtering centrifuges, decanting centrifuges, and centrifugal separators. The centrifuge has a cylinder that revolved in very high speed circle the axle of its own, we called it the bowl, ususlly the bowl was driven by the motor. When the suspension (or emulsion) was feed into the bowl, it was driven quickly to revolve at the same speed as the bowl, with the influence of the centrifugal force, the suspension (or emulsion) would separate into different components, and discharged respectively. Generally, the faster of the bowl’s speed, the better effect of the separation would get.
      There are two action principles of the centrifugal separator, centrifugation and centrifugal settling. The centrifugation makes the centrifugal pressure that produced by the suspension under the centrifugal force field, to affect on the filtering medium, make the liquid become into the filtrate through the filtering medium, and at the same time the solid particles are hold on the surface of filtering medium, so to achieve the liquid-solid separation; The centrifugal settling applies the theory of different components with different densitied of suspension would be sedimentation and layering in the centrifugal force field, so to achieve the liquid-solid (or liquid-liquid) separation.
      There is another kind of separators that used for testing and analysing, that can be used on liquid clarification, concentration of solid particles, or liquid-liquid separation. This kind of separators have different structural patterns under different conditions such as ordinary pressure, vacuum, and refrigeration.
      The primary indicator to judge the capability of centrifugal separator is the separating factor. It registered as the ratio of the materials’ centrifugal force and gravity, when they were going to be separated in the bowl. Generally, bigger the separating factor is, faster the separation is, and better the separating effect is. Usually, the separating factor of industrial centrifuges is between 100 and 20000, the high-speed tubular centrifuge can reach 62000 on top, and the high-speed tubular centrifuge that used for testing and analysing can reach 610000 on top. The other element that can influence the capacity of centrifuges is the working area of bowl, larger the working area is, more capacity the centrifuge will have.
       The filtering centrifuge and decanting centrifuge, mainly extend the working surface of bowl circle by enlarge the diameter of bowl; Besides the Circumferential wall of centrifuge’s bowl, also can attach the working surface, such as the disk stack of disk separator and the inner tank of room separator, they both enlarge the settlement working surface.
       Except that, the more fine of the solid particles in suspension, the harder the separation process will be, and the fine praticles that carried by the filtrate or separating liquid will increase. In this case, the centrifugal separator could finish separation with a bigger separating factor; when the liquid viscosity is big in suspension, the separating speed will be slow; if the densities of components in suspension or emulsion are very different, that would be advantageous for the centrifugal settlement, but the centrifugal filtering of suspension doesn’t need 
       To select a centrifugal separator should depend on the solid particles’ size and concentration, density difference of solid and liquid (or two liquids), liquid viscosity, features of residue (or sediment), and the separation requirements of suspension (or emulsion). Users should comprehensive analyze according to those requirements, and satisfy the demanding of residue’s (or sediment’s) moisture and filtrate’s (or separating liquid’s) clarity, to decide which kind of centrifugal separators can be selected first. Then base on the capacity and the requirements of automation, to judge the exact type and specification of the centrifuges, and verify through the actual test at last. Generally, to separate the suspension within particles that the size of particles is more than 0.01mm, users can select the filtering centrifuge; to separate the suspension within particles that the size of particles is very tiny or can be shrinking and transmutative, users had better select the settling centrifuge; if the suspension has few solid content, the solid particles are very tiny, and the clarity of liquid requirement is high, users should select the separator.
        The future development trend of centrifugal separators must be strengthen separating property, expand larger centrifugal separator, improve the unloading devices, add  the centrifuges with special use and combined bowl, enhance research of separating theory and discuss the optimization control technologies of the centrifugal separating process.