Continuous centrifuges

Coppers and high copper aEoys can be successhEly cast using the centrifugal, continuous, investment, permanent, plaster, and sand molding methods. 

Properties of red brass alloys are given in Table 9. The members of this group are cast using the centrifugal, continuous, investment, and sand molding methods. General tensile strengths vary from 170 to 210 MPa (25,000—30,000 psi) minimum as cast in sand molds. 

Nozzle bowl centrifuge Continuous operation, high centrifugal force Poor dewatering... 

Type of Centrifuge Continuous Automatically Discharged at Full Speed Automatically Discharged at Reduced Speed g-Factor Range IFC) Minimum Solid Concentration in Feed [% by Volume (C ) Possibility of Washing Minimum Particle Size, mm Minimum Filtrability Coefficient (fr)(m/sec) Maximum Retention Time (Sec)... 

Centrifuges, continuous and laboratory Sterile saline solution (8.5 g NaCl/liter)... 

Centrifuge Continuous Full Speed Reduced Speed Range (F ) Volume tCiyl of Washing Size, mm (kHm/sec) 1 i m e (Sec)... 

Sedimentation centrifuges Continuous nozzle Botch tubulor bowl Botch disc bowl Botch disc bowl, selt Opening... 

Following centrifugation, continuously take out 1-ml fractions from the top of the gradient, and assay each fraction for particulate content (itis convenientto use radiolabeled(e.g., I-labeled) particulates). 

Figure 13.7. Comparison between (a) rate-zonal and (b) isopycnic centrifugation. Note that the gradient used in rate-zonal techniques is shallow, and if the centrifugation continues, the particles pellet. The diffusion process causes band broadening in rate-zonal centrifugation, but this is not evident when the particles are focused using isopycnic centrifugation.

The maximum density of the gradient usually does not exceed the density of the particles. Because of this, if the centrifugation continues indefinitely, the particles pellet at the tube bottom. The gradient is chosen to have the minimal density and viscosity possible to allow rapid separation and minimize diffusional band broadening. 

To recover solids in order of preference of thickeners. Section 5.10 and sedimentation centrifuges. Section 5.12 thickeners, deep thickener, rake thickener and tray thickener or hydrocyclone, batch automatic solid bowl centrifuge, continuous conical bowl centrifuge, continuous contour bowl vertical or horizontal centrifuge. 

Centrifuge, continuous extraction, 316 s/s including flexible connedions, explosion-proof motor, variable speed drive, ammeter, tachometer, excluding pumps, starter, flowmeters and control valves. FOB cost 220,000 at aqueous feed rated capacity = 2.2 L/s with n = 0.25 for the range 0.03-2.2 and n = 0.38 for the range 2.2-36. L-i-M = 1.70. L/M = 0.96. 

Requirements for achieving and maintaining uniform solids concentration throughout the tank—of interest particularly for slurry catalyst reactors and for feeding downsneam equipment (e.g., centrifuges, continuous stirred tank reactors, fluid bed coaters)... 

The above equation indicates that a thick layer thins out more rapidly than a thin one. This in turn indicates that a nonuniform layer should become increasingly more uniform as centrifugation continues. The following empirical relation approximately models the height of the thin film, h, for a constant evaporation assumption ... 

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