This technology is OLD stuff, over 50 years ago....plus minus. Used very successfully to bounce on the underside of the wires and keep the screencloth clear. AND ya know.......it friggin works....and works well.

>>>>>>>>>>>

new technology today attempts to do the same job by having adjustable angles, to increase FPM travel rates, but this truly can not be beat by the physical action of the balls hitting the cloth.

>>>>>>>>>>>

FOR an example for you: we sell 5x12 2dk screeners....and on the bottom deck we quite frequently sell with a ball tray below the second deck. The ball tray design is as follows: the bottom deck structure is divided into 12" approx. squared, 1 1/4" bottom screen cloth (below the 2nd deck) and 272 ball tray cleaner balls. These balls are kinda like the old "indian rubber balls" we grew up with 4 or 5 balls per square.

The other thing is: there must be enough SHAKE AND BAKE, "STROKE" to activate the balls and make them actually hit the underside with some inertia. So the position of the wirecloth can not be TOO LOW below the second deck to be effective.

LASTLY, we use a self cleaning T304 S/S flexmat, Cobra-Wire or similar wirecloth to stop the plugging from starting in the first place.

Good Luck to UNPLUGGING your world !!! ■

here you go.

Attachments

cec oregon trip 117 (JPG)

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THe easiest way would be to proceed with Mr George suggestion of ball trays - you can refit them on existing screens. other options like flexible mats or bivitec or liwell would be effective but you are looking at new screen. ■

Screen cleaning with mesh cleaning balls is one of the key features of Rotex screeners. The first Rotex screeners, built almost 100 years ago, already had mesh cleaning balls! And with great succes.

Like Mr. George Baker said, motion is important. The size of the pockets, the shape of the pocket as well as the motion of the screener are key factors for success or disaster. Without knowing more details about the type of screener it is difficult to say something useful about balls. ■

Dear Shri Prasad,

There are two aspects to prevent clogging of the screen cloth while dealing with very fine material with the tendency to stick / arch on screen cloth (such thing can happen as a consequence of material nature and or moisture content).

1) The screen design feature should use suitable frequency and amplitude. While dealing with fine material having tendency to clog, it is observed that high frequency screen tends to reduce the clogging effect. Such screen will have comparatively lesser amplitude.

2) The use of rubber ball resting on the screen cloth. The rubber balls are loosely tied by cord. So they remain on the cloth without falling down. The rubber ball size and weight should not damage the screen cloth.

The combination of above two will keep the screen free from clogging. As I know, the screen used for fertilizers (which have tendency to stick) have very high frequency. The screen experts can suggest better / other views.

The right design feature of the screen relies on field data and previous experience, and it cannot be decided purely by theoretical calculations. Calculations are applied on the earlier observed reference / similar data.

Regards,

Ishwar G Mulani.

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

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916 ■

Dear Ishwar: the balls of which i spoke are not loosely tied by cord. these bounce freely (2" dia) on a support wirecloth below the screening deck and hit the underside of the screening cloth to clear any potential plugging.

sincerely GB ■

george i would love to hear more about this ball option. have you any other pics?

sounds like a very usefull option, what kinda cost is involved on say a 20ft*5ft screen ■

dear redtrev: this is old technology over 50 yrs old and well proven. IT WORKS.

basically, the 3rd deck of a screener box, typically being the finest cut......which by default also makes it the MOST DIFFICULT separation. Under the 3rd deck a ball tray deck arrangement is installed usually without welding and attached by T BOLTS or similar to grab the rails above. Must be installed in proper distance below the deck and the balls, are usually 2" diameter, kinda like indian rubber balls from when we were kids growing up, typically 4-5 per 12" square compartment. The balls bounce up hit the wirecloth underside and keep the wires from plugging or blinding. This assumes your screener has enough UMPH.....OR G FORCE or ACTION or stroke with SPEED to hit the underside with some force and clear the plugging or blinding wirecloth.

USUALLY we also incorporate a TYLER COBRAVIBE WIRE, FLEXMAT type or similar

Stainless steel self cleaning wirecloth slotted design screencloth.

i will dig out some more pics for you and send in a bit. HOPE this helps.

Wishing you a non blinded day! Happy Shaking! ■

thanks ill look forward to the pics ■

go to www.crsni.com see new better flip flow screen ■

You may want to try an "S" style screen. These are similiar to a Harp, however, the wires continually vibrate from one another which makes the material bounce. Also, because of the moisture content and the materials you are working with, I would use stainless steel. If you'd like a quote, please call me at (888) 464-9473 or e-mail julies@twincitywire.com. Hope this info. will help you can also look at our website www.unifiedscreening.com ■