Material is particularly adhered to belt surface if the conveying material is sticky, or in highly humid 

environment that results in accumulation, equipment damaged, or belt transverse-displacement.  Rollers with rubber discs help efficiently avoid build-up on the belt and incrustation on rollers.

It is easy to maintain the spring tensioners, only be adjusting screws.  Also, it is suitable for conveying material, such as coal, salt, etc.