Rolling drum

Figure 12.9. Rolling drum granulator sketch and performance, (a) Sketch of a rolling drum granulator (Sherrington and Oliver, 1981). (b) Effect of rotational speed on size distribution (1) at 20% of critical speed (2) at 50%. (c) Performance data on commercial units (Capes and Fouda, 1984).

Inorganic Products.—General rules for the application of certain types of dryers cannot be given as there are too many variations in the nature and quantity of the products to be handled. Usually rotary vacuum and drum dryers are used for delicate products, and direct-heated or steam-heated cylindrical rotary dryers are used for bulky materials that are not affected by higher temperatures. Chamber and shelf dryers (either atmospheric or vacuum) should be used for all delicate and sticky materials, also pastes, and in cases where the material is strongly acid or alkaline, as the trays that are placed on top of the shelves can be made of almost any kind of material which will prevent contamination of the product. Sticky material and paste can also be handled successfully on either a single or double roll drum dryer. 

FIG. 21-153 A rolling drum granulator [Capes, Particle Size Enlargement, Elsevier, 1980). 

The Rolling Drum Dust Generator described in a recent BMHB review54 is a variation on the same idea except that it uses a tumbler similar to those used in attrition tests for the dust generation and a cascade impactor to sample the dust cloud. 

To maintain a constant 90° angle during peel, a special jig is necessary that moves the test panel at the same rate as the tape is being stripped (Fig. 2a). An alternative method [9] is to apply the tape to a free-rolling drum, which automatically maintains 90° by rotating during the stripping process (Fig. 2b). 

Figure 3. Modern one-piece cast drum half Figure 4. Rolled drum barrels...

Using tray fermenters or rolling drum fermenters instead of highly sophisticated... 

Make adequate provisions to prevent runaway rolling drums. 

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