Centrifugation settling velocity

Here again an equation is estabUshed (2) to describe the trajectory of a particle under the combined effect of the Hquid transport velocity acting in the x-direction and the centrifugal settling velocity in thejy-direction. Equation 13 determines the minimum particle size which originates from a position on the outer radius, and the midpoint of the space, between two adjacent disks, and just reaches the upper disk at the inner radius, r. Particles of this size initially located above the midpoint of space a are all collected on the underside of the upper disk those particles initially located below the midpoint escape capture. This condition defines the throughput, for which a 50% recovery of the entering particles is achieved. That is,... 

Equipment. Centrifugation equipment that separates by density difference is available in a variety of sizes and types and can be categorized by capacity range and the theoretical settling velocities of the particles normally handled. Centrifuges that separate by filtration produce drained soflds and can be categorized by final moisture, drainage time, G, and physical characteristics of the system, such as particle size and Hquid viscosity. 

Continuou.s Centrifugal Sedimentation Theory The Stokes settling velocity of a spherical particle under centrifugal field is given... 

For example, at n = 1200 rpm = 20 liter/sec and r = 0.5 m, the settling velocity in the centrifuge is almost 28 times greater than that in free settling. Note that the above expressions are applicable only for Re > 500. For small particles. Re < 2, migration toward the wall is laminar. The proper settling velocity expression for the gravitational field is... 

The ratio of settling velocity in a centrifuge to that of pure gravitational settling is ... 

If the centrifuge operates at 4000 rpm and the particle s distance from the axis of rotation is 0.25 m, the settling velocity is only 0.01 m/sec, which corresponds to ... 

We have an emulsion of oil in water that we need to separate. The oil droplets have a mean diameter of lO " m, and the specific gravity Of the oil is 0.91. Applying a sedimentation centrifuge to effect the separation at a spedd of 5,000 rpm, and assuming that the distance of a droplet to the axis of rotation is 0.1 m, determine the droplet s radial settling velocity. 

Determine the settling velocity of a particle (d = 4 x 10" m and Pp = 900 kg/m ) through water in a sedimentation centrifuge operating at 4,000 rpm. The particle velocity is a function of distance from the axis of rotation, as shown by the following data ... 

A cyclone separator is an economical device for removing particulate solids from a fluid system. The induced centrifugal force (see Figure 7-6) is tangentially imparted on the wall of the cyclone cylinder. This force, with the density difference between the fluid and solid, increases the relative settling velocity. 

Overall coefficients, 332 Vertical plate coil, 331 Hindered settling velocities, 231, 236 Horsepower, centrifugal pump driver, 201 Hydraulic performance, calculations, 180-188... 

The terminal settling velocity u, for a single spherical particle in a centrifugal separator can be calculated from equation 9.5 with the centripetal acceleration rto2 replacing the gravitational acceleration g to give... 

Eq. (1), known as Stokes law, gives the terminal settling velocity of a spherical particle settling in the laminar region (Stokes region) under the influence of a gravitational or centrifugal field. 

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