Dear Mr. Gary James,

You have conveyor of belt width 1500 mm. So, width of the material on belt would be around 1300 mm. The screen width is 3700 mm. So, if you want to feed from conveyor, the chute you provide should widen the flow to at least 3400 mm. For this, you will have a sloping face in the chute where the material will fall, and on this sloping face you have to put flats to disperse the material sideways (flats as if coming out from a point / line radially). Then, this material has to fall on a stone box to reduce the velocity, and then it has to flow on to screen. The flow widening on the sloping face cannot be by more than 5 degree. It will be a big chute demanding height and various dimensions.

The better option is that you have chute described as above but smaller in size and feed on to a slow speed wide belt and small length conveyor (like belt feeder). Then appropriately feed on to the screen. Alternatively, one can also use vibrating feeder of appropriate deck width, just to widen the material flow.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

A few points of interest.

Have I ever seen direct feed to a screen with no feed plate or other.......YES.....was it a problem......absolutely on conventional vibrating screen decks.

Conventional design .......deck would all be at same angle of decline and would have a feed plate to hit with the oncoming material to take impact, abuse and try to SPREAD sideplate to sideplate. This why there is a feedplate.

Conventional box has one drive moving all components.

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The banana is a number of segments - bolted together as independent movements. .... and at independent/differential deck angles. so.......

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When you say the top deck is all SOLID RUBBER....basically the first or primary feed receiving segment is heavy duty lined to take the impact of the material. Rubber is probably a good choice there. The first segment, if you will is basically acting as a FEED PLATE to the rest of the length of screening area.

Banana screen was basically developed to keep the SIZE OF THE MECHANICAL DRIVE down....too big bearings, too hot, mechanically problematic. The banana design allows lots of OPEN AREA.....lots of tonnage availability.....ie ten feet wide x 24 feet long.......perfect to handle large tph and volume.

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SPREADING TO TEN FEET wide is always always a problem...the wider the harder to spread out quickly and use the full width. Getting a conveyor close to the width of the screen is typically ideal. Using some moulded in inverted V SHAPED risers will help move the material to the outside of the decks.

George Baker......Moderator......hope this helps ■