Hi Tevan,

There is quite a bit more to designing chutes than it may appear and, whilst grain is a relatively easy material to handle, much depends on the silo/truck arrangement as to the best method to affect the transfer. I am wary of advising without specific details of the whole circumstances. I would advise you to go around and see a few applications and talk to engineers on the ground, to secure a basic understanding of this type of duty.

As for belt conveyors, there are many types. CEMA has a basic book on US standards for trough belt conveyors and Ishwar G Mulani is Author of the Books :- ‘Engineering Science and Application Design for Belt Conveyors’ and - ‘Belt Feeder Design and Hopper Bin Silo’, that provide good guidance on this subject. Why re-invent the wheel. There are many experiences suppliers of conveyors that it would seem prudent to consider proposals from established manufacturers. I have to say that it would seem a bit hazardous to go into designing grain handling equipment without having any experience or colleagues to turn to for advice. ■

May I second the comments by Lyn Bates.

Even with grain, it seems foolhardy in the extreme to attempt the work outlined by seeking advice on forums like this and no proir experience! ■

Dear Mr. Tevan,

You have mentioned that you intend to design chute and belt conveyors, which would be first time. Elaborate engineering science is involved in designing of belt conveyors and to certain extent also in designing the chute. In such situation, you can have following options to deal with your assignment :

- Firstly you should visit some material handling plant and see the concerned items.

- You should try to collect, applicable literature, publications, for the concerned items. It would be unwise to do it from scratch.

- There will be also certain standards and codes to which your design has to conform, depending upon the country, so it is very much essential that you should also have copy of applicable codes, standards in accordance with the rules and regulations in your country.

- Conveyor design is concerned with mechanical engineering, electrical engineering, structural, civil engineering and instrumentation. So, one also needs to have pertinent knowledge about these engineering fields.

- The other option is to assign the design work to consultants, which will ensure reliable equipment and at the same time will provide you the opportunity to know the design engineering of the subject items.

The design engineering of belt conveyors is a huge subject and you will get very scanty information on forum, which would be inadequate for the work.

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 ■

You could read 'Chute Design - Problems, Causes and Solutions', by The Bionic Research Institute, PO Box. 465 2100, South Africa. ■

I think the best approach would be to consult a specialist, as the cost of being wrong can far outweigh the saving of a do it yourself job for performance related equipment. ■

1 - You don't need to design a belt conveyor. A more practical way is to contact a manufacturer of belt conveyors - and let them do the calculations for you on their computer. You can learn the rest later.

2 - How big a tube do you need out of the silo? I take a plastic bucket, weld into it a 50 mm tube, fill it with the product and test how it runs. I measure the weight of product flowing per second, the angle of repose, the angle of draw-down, and the bulk density. That gives some basic design information.

Then I estimate the flow in the real tube based on the Area Ratio to the small tube. A 100 mm tube would allow 4 time the flow of the 50 mm. This is conservative - you should get flow proportional to a power of 2.5 instead of the 2.0 assumed on the area basis.

3 - A 50 mm tube will not tell you if there is likely to be any flooding or dumping of product due to ratholes in the silo. To control that you may need a flooded feed at the conveyor which can throttle excessive dumps of product.

That is not the whole story - but it's a tip from personal experience. ■

I tend to agree with the responders who advise you to look at current manufacturers products. There are plenty out there - look at www.world-grain.com

You have to remember that grain is not a single product. Its flow characteristics depend on type - wheat, corn, pulses, oilseeds, etc, its moisture content and its standard of cleanliness. Is it straight from the field, or after running through a pre-cleaner or drier? ■