There are previous threads relating to this topic. One was started just last week. If you read the article and the links referenced therein you will get a better idea.

That apart, the minimum curve radius is not so easy to find. It is dangerous to tighten the bend if you are not sure how the load will perform.

Four years ago I had a petcoke system which the FEED Contractor had originally designed using pipe conveyor flights with some very tight bends. Being a raw Oil & Gas merchant he sought advice from a reputed major handler of petcoke from Louisiana. These guys advised the Roman FEED Contractor that he could get away with troughed belts. They took his word and promptly changed to troughed belts. Oops, they forgot to recalculate the bends. At the EPC stage the German sub-Contractor insisted the curve radii could not be met. I was the Owner's Engineer, not representative (because an infidel cannot speak for Arab Clients), and I agreed with the EPC sub-Contractor. My investigation outshone the US & UK feeble attempts at snooping and when I discovered the history I advised the Client and got off the job pronto.

Horizontal curvature is simply a plant layout exercise. Take the largest bends you can safely get away with. Then leave it to the Civil fraternity to ridicule your efforts: but stick to your guns: officially. Sleep well: it's not your money....I hope! ■