Greetings urwith dilup,

Short of using a dedicated pnuematic transfer sytem into a pnuematic tanker trailer or a sealed building to load the fly ash you do no have many options.

The simplest solution will probably be one where you have a pair of canvas curtains just like a window curtain in a home with an hydraulic loading spout -referred to as a donkey dick in the trade.

by pulling the canvas curtain on both sides of the lorrie effectively blocking the wind you have a minimal area of dust.

Do you roll a trailer tarpaulin on your lorrie trailers before your fly ash is transported? ■

Please use road closed tankers for handling ash type products.

These are fitted with self pneu. unloaders.

Anything else is a waste of time.

Cheers

James ■

Your initial post notes, "Addition of water is not possible due to presence of unreacted lime in the ash that leads to immediate solidification of the ash which becomes unusable." United Conveyor Corporation has developed our Pin Paddle Mixer/Unloader for the purpose of conditioning high-calcium ash (such as that produced by a CFBC) with water for unloading into open top trucks. A mixture free of visible dust and one that will not solidify in the disposal truck can be obtained. If the ash is intended for disposal and not for sale, wet conditioning with a Pin Paddle Mixer/Unloader would be recommended.

Please send me your eMail address and I would be pleased to send you additional information. ■

Dear Sir,

Why donot you try Energo's Closed Tanker Telescopic Chute .

We are one of the leading manufactureers of material handling systems in india , specifically a pneumatic conveying expert .

with our telescopic chutes and a special arrangement for venting which we mount on the tankers itself, no doubt increases your maintainance cost will shoot up but gives you a satisfactory solution for the specific problem.

For More Information Contact:

Scahin Kumar Arora

Energo Engineering Projects LTD

New Delhi

energo@energo.co.in

91-11-26385323 ■

Allowing free fall is inviting serious dust problems due to the dilatation during acceleration and the extensive boundary conditions. This is often associated with direct gravity discharge from the storage silo, which is almost invariably not mass flow, so the collapse of a dynamic arch within the hopper neck is entraining air and aggravating the turbulance.

The provision of a well designed screw feeder with plug discharge will reduce the rate of void air demand of expansion in the hopper outlet region and deliver a more coherent product, particualrly if means are provided in the outlet region of the hopper to expand the flow channel and induce a degree of accelerated de-aeration. Direct end discharge via an inclined chute will substantially protect much of the vertical displacement, more so if the chute is adjustable, to lay the delivery into the vehicle.

Alternatively, the use of an extending chute fitted with an internal probe that raises the bottom when the product reaches a certain hight, will confine the fall and allow only suface repose conditions to be exposed. A large diameter lower section is needed to accomodate the fill rate at small formed cone sizes, unless the vehicle fill is formatted by a lower chute housing that is profiled to the aspect ratio of generous wall clearances inside the waggon

Each application should be considered individually and total dust elimination may not be practical, but conditions can generally be significantly mitigated by careful design and attention to detail. ■

Listen to what James Morrish has said. There is no other way to eliminate dust in this situation.

Michael Reid. ■

Since you already use some closed trucks why not do like the Oz's say & standardise on closed trucks i.e put lids on the tippers, with holes for the spouts. I wish they were all so easy!

What happens at the unloading point? ■