Vibrating screen decks

Fig. 5. Schematic diagrams of screens (a) vibrating grizzly, (b) double-deck vibrating screen, and (c) a rotating probabiUty screen (2). A schematic...

Data for dry screening on a 20-mm square aperture vibrating screen (8) indicate that the screen is relatively efficient, giving an apparent bypass value of 0.5%, sharpness index of 0.8, and a cut size of 20 mm. On the other hand, results (9) from a plant operating an 8 ft x 20 ft (2.4 m x 6.1 m) double-deck screen with 16 mm woven wire bottom screen deck gave an apparent bypass of 4%, sharpness index of 0.56, and a cut size of 17 mm. Data (10) for smaller... 

For vibrating screens, the suitable parameter A is the screen deck area multiphed by the length in m. Cost includes dtive- and feed-boxes, and excludes motor, starter, and screen cloth. For spinal classifiers, the suitable parameter A for costing is the spinal diameter, in cm. Cost includes the motor. For hydtocyclones, the suitable parameter A for costing is the cyclone diameter, in cm. Cost includes fittings and combination urethane-ceramic liners. The appropriate values of X and the coefficients ate given in Table 4. 

High speed vibrating screens. . , Rod Rod - deck screen grizzly ... 

Vibrating screen, horizontal Horizontal screen deck motion pulsed up/forward, then hackward/down Dewatering and close sizing... 

Vibrating screen Inclined screen, deck motion Crushing circuits, scalping,... 

The screen deck may be made from woven or welded steel wire mesh with square apertures. Such decks have a high proportion of open area and are relatively inexpensive. However, they have a low resistance to wear and corrosion and produce high noise levels when vibrated. Woven wire decks with rectangular apertures are sometimes used to reduce pegging. 

The most widely used design is the inclined vibrating screen. These use decks at some 15° to 20° to the horizontal mounted on a vibrating frame to transport materials across and through the screen. Such screens can be used in series to produce a number of sized fractions. Alternatively, multi-deck screens can be used, in which two, three, or even four decks are mounted on one frame, with the largest aperture mat being at the top and the smallest at the bottom of the frame (Fig. 5.8). With all designs, the material should be fed uniformly across the width of the deck at a steady rate to maximise the effectiveness of the screen. 

Vibrating screens, 1 deck Surface area. A, ft 32-60 ft Cp= 1,100 A Carbon steel... 

Double-deck vibrating screens commonly are used for this purpose. For sizing below 12 mm, wet screening is done, using either high frequency vibrating screens or the Sieve Bend. Details on size reduction can be found in various books on coal preparation. ... 

Screening Stttfaces It is generally agreed that the most efficient screening results when a series of single-deck screens is used. This is true because lower decks of multiple-deck screens are not fed so that their entire area is used and because each separation requires a different combination of angle, speed, and amplitude of vibration for maximum performance. 

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