Chamber centrifuge

The main types of industrial centrifuges used for bioparticle separations are the tubular, the multi-chamber, and the disc centrifuges Figure 11.8). The disc centrifuge may have nozzles to allow continuous exit of the concentrated suspension. The nozzles allow operation in a continuous mode, with Rf > 0. Tubular and multi-chamber centrifuges operate with... 

Highly dynamic breakup phenomena which are common, for instance, in contact-free liquid dispensers, are also possible, but rarely used. This means that the liquid handling performance can be made widely independent of the flow properties, in particular the viscosity of the processed liquid. Within the chambers, centrifugally induced buoyancy efficiently supports the removal of gas bubbles from the liquid bulk. 

The efficiency of the multi-chamber centrifuges is high because of the long residence time of the liquor in the unit. A mathematical model similar to that used for the tubular centrifuge can be applied to the multi-chamber centrifuge provided that satisfactory assumptions and modifications are made. 

The cleaning of multi-chamber centrifuges is more difficult and takes longer than for the tubular type. The manual discharge generally limits this type of machine to suspensions containing less than 4—5% solids by volume. 

Available speeds range between 4500 and 8500 rev. min , flow rates from 2.5 to lOm h and bowl diameters from 335 to 615 mm. Multi-chamber centrifuges, apart from the separation of grinding swarf from cutting oils already mentioned, are mainly used for the clarification of beer, wine, fruit juice and varnishes. 

Prewet a Millipore UltraFree-MC with 5 pi of H O. Centrifuge at 10,000 rpm for 1 minute, and then remove any liquid from the bottom of the tube. Pipette the probe mix onto the side of the UltraFree chamber. Centrifuge the droplet through the column and collect the liquid ( 10 pi). 

Beckman Elutriation Method. The Beckman elutriation method uses a chamber designed so that the centrifugal effect of the radial inward fluid flow is constant (Fig. 3). The separation chambers are made of transparent epoxy resin which faciUtates observation of the movements of the cell boundary in strobe light illumination. This enables detection of the radius at which the cells are separating. When a mixture of cells, eg, mononuclear white cells, enters the chamber, separation can be achieved by fine tuning centrifuge speed and inward fluid flow to the specific cell group. This is a laboratory method suitable for relatively small numbers of cells. Chambers are available in sizes to handle 2-3 x 10 , 1 2 x 10 , and 1 x 10 ° cells. The Beckman chambers can be appHed to collect mononuclear cells from bone marrow aspirates. 

Comparisons are available on the relative performance and costs for dewatering municipal sludges (2). The relative performance of different filters and conditioners on waste sludges is shown in Table 3. The same sludge was treated on two belt-filter presses, two different centrifuges, and rotary vacuum filter (75). In another study, a variable chamber filter press, fixed-volume filter press, continuous belt-filter press, and rotary vacuum filter were compared for performance, capacity, and capital and operating costs (69). 

Fig. 10. The Groth ZG 5 centrifuge. R, rotor R, stationary shaft T, Teflon seal K, K, chambers for gas scoops S, S2, scoops V, gas supply M, manometer Z, Z2, tapping points for enriched and depleted gas P, P2, vacuum chambers E, electromagnet for eddy current heating Tb, Tb2, temperature measuring devices K, cooling coil and D, D2, labyrinth seals.

TABLE 12-36 Some Materials That Have Been Successfully Spray-Dried in a 6-m-Diameter by 6-m-High Chamber with a Centrifugal-Disk Atomizer ... 

The critical dimension of a centrifugal-disk chamber is the diameter. Vertical height is usually 0.5 to 1.0 times the diameter the large cone is needed mainly to accelerate to the discharge duct and prevent settling it contributes httle to drying capacity. 

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