the best way is to have your belts covered with all weather belt covers and have your transfer points enclosed to prevent fugitive dust escape unless you want to spray water at every transfer

point. ■

Hi Shajan,

The answer is you can by very careful design of the transfer chute. This is best done by specialists as it requires careful material flow control but the principles are,

> Control the material flow

> Minimise the induced air flow across the material in the transfer

> Do not let the material impact onto the receiving belt displacing air but instead flow it onto the receiving belt using a well designed deflector

> use rubber to seal the conveyor transfer as best you can to minimise the induced air flow

> Use baffles within the open spaces of the transfer to reduce the residual induced air flow so that any fine material picked up (ie dust) will settle

We have had great success using these principles such that we get much better results than using a baghouse or similar. In fact we do not recommend baghouses as they actually increase the air flow and this adds to the dust levels

All the best

Col Benjamin

Gulf Conveyor Systems P/l ■

We have material handling experts with dust control experience in our Mumbai office, who could help you with your chute design.

Also, you may want to consider creating a negative pressure inside your chutes to minimize fugitive dusting and installing dust collection / suppression equipment.

Sandwell India

602/603 - Powai Plaza

Central Avenue

Hiranandani Gardens

Powai

Mumbai, India 400076

tel: 91 22 6772 6666

fax: 91 22 6772 6677

Attn: Peter Leekha, Managing Director

email: pleekha@sandwell.com

Paul Janze

Sandwell Engineering Inc.

Vancouver, BC ■

Hi Paul,

After a great deal of research we have found that any dust collection system that basically collects the dust by drawing air across the material surface significantly adds to the dust problem so we try to avoid bag houses and the like. The key to dust control is reducing air flow, not increasing it.

All the best

Col Benjamin

Gulf Conveyor Systems P/L ■

Dear Mr. Shajan Kuruvila,

Your query does not mention certain basic information about the belt conveyors. It would be better if you mention following information :

1) Belt width

2) Belt speed

3) Material particle size & its gradation

4) Average length of conveyor and number of conveyors in your plant.

5) What kind of equipment you are using to create original feed in to conveyors. What about the dust problem at stockpile or other places.

If you have integrated plant then dust problem should arise at many points whereas you are referring to only belt conveyor. Belt conveyor on its own if properly designed, will not generate dust during conveying. Only points are the feed point and discharge point.

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.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

I was once on the top of a long concrete silo block where the silos were being filled with a dry granular material conveyed by an open belt conveyor. As the sun shone through the roof lights I still remember seeing a fine column of dust rising from EACH set of idler rollers. On their own each column of dust was minimal, but combined over the silo length the visibility down the silo was markedly reduced.

This I have seen with my own eyes! ■

Put a lid on it! ■