Built by a shaft less screw that rotates to the inside of a trough (tubular or U-section) with one or more loading hoppers and one or more exhaust mouths. The rest of the machine is closed by covers. The absence of the inner shaft allows the transport of sticky materials, usually difficult to transport by the screw with shaft. The bottom of the trough is being protected by a wearresistant coating in HDPE or steel depending on the material to be conveyed.
The configuration of the conveyor can be ”pull execution” or “push execution” depending on the general arrangement of the facility. The overall length can be easily adapted to the layout. The slope varies between 0° to 30° with a progressive reduction in efficiency: as a general rule, the flow at 30° is reduced by 50% compared to that at 0°, however the actual range depends on the material transported.