Scroll-type centrifuge

The major advantage of this system is elimination of the 14-scroll type centrifuges and 26-nozzle type machines used in the GCOS plant which have had excessive replacement, maintenance, and repair costs because of the abrasive action of the fine solids on these high speed, precision machines. 

Tubular centrifuge Multichamber centrifuge Imperforate basket centrifuge Scroll-type centrifuge Disc centrifuge... 

Gibson has published some interesting results of tests with a scroll-type centrifuge, which show the cut size as a function of the feed rate and feed solids concentration—see Figure 7.8. 

Polyelectrolytes are widely used for the flocculation of slurries to be separated in the scroll-type centrifuges the point of addition varies depending on the type of polyelectrolyte and the type of slurry. Anionic polyelectrolytes... 

Figure 7.8 Effect of feed concentration and flow rate on cut size X50 for scroll-type centrifuge...

Figure 7.9 Scroll-type centrifuge dewatering performance declines at a critical...

The scroll-type centrifuge has found a wide variety of industrial applications as a clarifier for example, it is used to recover crystals and polymers. Most recently it has been used widely in the UK for the dewatering of both municipal and industrial sludges . Stahl has successfully applied the centrifuge to the dewatering of coarse solids, namely PVC particles with a median size between 100 and 190 pm. Some of his results are shown in Figure 7.9. 

Another major area of application of the scroll-type centrifuge is in the classification of solids such as kaolin coating clay, Ti02 etc. 

Solid bowl scroll decanter centrifuges have also been built vertically. The pendulum-type construction allows the bowl to expand more easily when operating at higher temperatures and makes mechanical sealing for elevated pressures less cumbersome. Although these units have been designed for operation up to 10 bars, they often operate at 5 bars or less. 

FAN, CENTRIFUGAL - A fan rotor or wheel within a scroll type housing and including driving mechanism sup ports for either belt drive or direct connection. 

Scroll centrifuges discharge solids continuously and usually drier than disk and imperforate batch types. Generally disk centrifuges have the highest values of Z or KQ for a given size and therefore the best ability to collect fine particles at a high rate. 

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