Double-roll crusher

FIGURE 6.8 A double-roll crusher. (From Meyers, R.A., Ed., Coal Handbook, Marcel Dekker, New York, 1981, p. 188.)... 

This double-roll crusher has the advantage of greater flexibility due to a variable gap setting, less fines production as compared to the single-roll crusher since the tooth-plate contact is absent, and a smaller limit in product size, depending on the type of teeth used. However, double-roll crushers have been cited to be more difficult to maintain in this heavy service, are more expensive, and may offer no particular advantage. 

Crushers and Breakers. Many types of crushing and screening equipment are used commercially. Representative types are the Bradford breaker, single-roU crusher, double-roll crusher, and hammer mill. 

The secondary crusher, which is located within the plant, consists of a McLanahan 48 x72 Heavy Duty Double Roll Crusher rated at 1,500 TPH. Because of its design, the manufacturer believed that the crusher could handle an increase in capacity without any modifications. Therefore no modifications were made. 

Prater Industries, Inc., offers a double roll with heavy-duty teeth as a precrusher feeder. The Mikro roll crusher (Hosokawa Micron... 

Roll crushers are available as smooth or toothed rolls. Figure 12.6(b) is an example of a smooth-roll crusher and Table 12.10(b) presents data for a double tooth-roll crusher for coal. For smooth rolls, the feed size is hmited by the angle of nip, which depends on surface conditions but it is approximately 16 degrees. Table 12.10(c) contains additional operating data for roll crushers. The relation between the diameters of the roll d, and feed df and the gap do between the rolls is given by... 

Double-roll (or twin-roll) crushers with 1800 mm roll diameter and approximately equal effective roll width attain throughputs of 1000-1200t/hourfor a gap width of about 250 mm between the rolls and can accept feed material up to 1000 mm in size. 

Coke for carbide production is crushed in two crushing units of three sets of double crusher rolls each, and dried in four rotary driers 5 4 feet diameter by 40 feet long. This prepared coke is stored in four concrete silos of 160 tons capacity. 

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