for withstanding a component of the weight of and the lateral thrust from the material being conveyed and finally two rows of rollers 30 that perform a function similar to the rollers 30 in fig6 it may be observed that the risk of the belt taking up a rounded section and twisting increases as the shape of the set cross section is closer to a circle that amounts to saying that the risk increases with increasing number of faces in the cross section in fig7 the risk is reduced by the presence of three narrow strips 14 facing the rows of rollers 20 and 22 the risk can be further reduced by providing additional narrow strips facing the rows of rollers 30 in some cases the belt is intended for a conveyor that has rising portions that are designed to raise the material being conveyed in which case the conveyor belt may also have lugs plates or vanes which once the conveyor belt has been 34 closed 34 in cross section by the rollers of the framework constitute partitions that leave little leak space fig8 and 9 show a belt of the same kind as that illustrated in fig3 but further including triplets of triangular vanes 32 at regular intervals in the longitudinal direction each vane coinciding with a respective one of the narrow strips 14 these vanes are triangular in shape so that when the conveyor.