with a distance that short it will cost you less to have a covered high angle troughing conveyor. ■

Dear Shri Prabhu,

You have mentioned conveying distance as 100 m and capacity around 200 mtph. What about the lump size? If capacity is the only basis and lump size is not large, then you may be using approximately 200 mm diameter pipe conveyor. In this situation, about 7 m distance would be needed to convert flat belt into pipe at each end. That means, you might have actual pipe conveyor of about 85m length. Pipe conveyor is expensive compared to the trough belt conveyor. Using the pipe conveyor would be justified if the material is powdery and dusting is issue or you have curvature in horizontal plane etc.

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 ■

Based on the average angle (arctan(0.3) = 16.7 degrees) it is not clear if you need a high angle conveyor. I believe that you do. Our DSI Snake Sandwich High-Angle conveyor will easily take care of your requirements with modest belt width say 750 mm or 900 mm depending on lump size and size distribution.

Joseph A. Dos Santos, PE ■

Dear Mr. Prabhu,

Pipe conveyor for 100 mtr is possible and approx. 20-35% costlier depend upon layout. We have also supplied for 70 mtr.

You can also install a troughed belt conveyor for this purpose. However if you wish to elevate the material within very short horizontal distance you can go for steep angle conveyor system. It all depend on your layout. You may send me the lay-out drgs, for exact calculations and better solution.

regards,

Ketan Trivedi

Fairtech Engineering Co. ■

Depending on the size fraction of limestone, a 17 degree slope, using a conventional conveyor, is quite adequate.

You can apply a pipe or deep trough fabric belt. If the lumps are large (>100mm), then you need to install an inexpensive containment/inhibitor system for protection against bouncing lumps. There are many hard rock installation, with slopes greater than yours in hard rock. This is not novel.

Mr. Mulani is correct is his advice on the cost difference between pipe and conventional. I believe the non-pipe will be the least cost option. ■

Dear Shri Prabhu

Most of the above comments are valid.

The pipe conveyor can do a job with these perameter and we have installation as short as 50m. With limestone an angle of 16/17 deg is OK.

It is likely to be more expensive than conventional but if you are considering to totally cover the conventional system or you have some sort of curve to negotiate then there is additional benefit.

Paul Holt

Dosco Overseas Eng Ltd. ■

I define deep trough to be any angle greater than 35 degrees, which appears to be the default selection.

Sometimes we shorten the center roll to increase the wing roll length supporting belt that provides greater capacity and greater steering control in horizontal curves.

There are many belt and idler construction details that depart from the published norms. Some of the participants, here in this forum, have made many claims on their pro and cons. We can only claim to our technology. We tend not to publish advanced methods that depart from the norms and that demonstrate significant benefits according to our studies.

By example, see the coming publications on the 20.3 km Curragh overland, now operating since April in Queensland Australia. Its has many technology firsts.

Since we must compete with many other technologist, we do not divulge these details. If someone wishes to become a partner in oursuing overland projects, we are available. ■

Larry,

Don't we all have a moral obligation to share our knowledge and experience to advance the technology?

Joe Dos Santos ■

Moral obligation? 1200 posts to various requests - shared much and got little. Who cares?

Moral obligation? Tell me to make a $9 million dollar investment and then give it away? Stupid, yes. Dumb no.

Where does the next job come from? All the whana-bees will make similar claims. Then off to the soup line.

Who is interested? All those who will not make a similar investment.

No different than any hi-tech company. Those that have do and those that don't won't.

Arose, needle and kajole - keep up the good work. Its just the tonic we kneed. ■

Dear Prabhu ,

Can you send layout ?

what is a lump size ?

I can workout entire design

Uditha Kohowala

udithausk@yahoo.com.sg ■