Sganesh,

The most obvious problem to me with weighing on a steep conveyor is the angle of repose for the material. This was described to me to be the angle of a cone shaped pile that the material will naturally form when poured. The angle for bituminous coal is roughly 18 degrees. It is rare to find an inclined conveyor in my area over 16 degrees. If you try to convey material at an angle greater than it's angle of repose, it will roll back down the conveyor or convey up the belt at a different speed than the conveyor. As Mr. Brown pointed out, the greater the angle, the less weight is sensed at the scale. At 45 degrees the change in weight is 1/2 that of level.

There are two basic signals needed for a belt scale weight and speed. If you can not sense the speed of the material correctly then the the belt scale will not integrate correctly. The steepest conveyor I have tried was approximately 18 deg. I would guess you might find some at 20 degrees, but you would need some pretty sticky material and a slow belt speed. Some other suggestions would be to use a multi idlers scale to increase the weigh area and scale born time. ■

Originally Posted by sganesh

Dear Experts,

Is it possible to install a weigh scale in the steep angle conveyors? If yes, what are the precautions need to be taken ?

Thanks & Regards,

Dear Mr Ganesh,

What is the angle of Inclination of the conveyor ? Does the material fall back while conveying?

Kindly clarify

Thanks & regards

Sundar

newtonws@gmail.com

09433039991 ■

Dear Shri Ganesh,

The belt weighers (belt scales) are regularly used on inclined conveyors. The quantity being conveyed is sensed by the effect of the gravity which is vertical. In case of incline conveyors, this influence will get multiplied by cosine of the inclination. If it is 90 deg incline (vertical), then downward gravity force will have no component across the conveyor and indication will be zero. This means the material thrust acting on the belt weigher will get diluted as the inclination increases (diluted means reduction in magnitude of thrust). This is compensated by use of cosine correction factor in the electronic system of belt weigher.

Please inform your conveyor particulars to the belt weigher manufacturers and they will recommend the solution, if it is not of unusual nature.

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

Email: parimul@pn2.vsnl.net.in ■

Dear Ganesh,

I aggree to the views of Mr.Mulani.

If the angle is varying like in a Reclaimer,I could never see a belt scale which gives the required accuracy.

In case of fixed slope conveyor an accuracy of 0.25% can be achieved provided the angle of slope is not more than 12 to 14 degrees

so that the material will not slide back.

Another problem faced is sliding back of coal in rainy days as slurry when the rate of flow reduces due to any reason.

Rgds,

Narayanan Nalinakshan. ■