Screw conveyors are used to transfer dust-type and small single-piece cargoes on horizontal and inclined panes (up to 20°), and rarely vertically. Conveyor has metal closed gutter, inside of which paddle roll is rotating, with paddles arranged on helical curve. Paddles can be blind (for free-flowing cargo), band (for humid and single-piece cargoes) and shaped as separate paddles secured onto the roll (for sticky and slump cargoes). Paddles push through cargo along the gutter during rotation of the screw. Screw conveyors consists of sections with length of 2-4 m, overall length generally does not exceed 60 m, gutter diameter 100-600 mm. Screw conveyors have simple construction, convenient in service, especially during transportation of dust-type cargo.
Technical characteristics:
| Screw diameter, mm | 200 | 320 | 400 | 500 | 600 |
| Screw step, mm | 160 | 250 | 320 | 400 | 400 |
| Rotations per minute, | 37,5 60 95 | 60 95 | 37,5 60 | 37,5 60 | 37,5 60 |
| Productive capacity, m3/h | 3,2 5 8 | 24 46 | 29 57 | 65 | 100 |
| Length, m | to 30 m | to 30 m | to 30 m | to 15 m | to 15 m |