For the transport of abrasive, pieced, and adhesive materials or for high performances up to about 600 m3/hr, we use robust axle-free spiral conveyors (types ST, STN). These are especially for the transport of highly abrasive materials (corundum grit, gravel, sand, crushed rock, grinding dust, blast-furnace and electrical power plant cinder, etc.), transport of materials with high granularity (PET bottles, wood, wood chips, paper, biomass, etc.), transport of adhesive and wet materials (waste sludge, soil, bentonite, pulp materials, etc.), and transport of very delicate and flowing materials (food powder, chemicals, fly ash, etc.).
With the correct application and technical design of axle-free spiral conveyors, we can solve an often complicated problem for the customer in cases where other types of mechanical transport cannot be used.
For extremely loaded conveyors (long transport distances, transport of materials with very high loose weight, etc.) robust spirals from two and three mutually connected profiles are designed. The thickness of the axle-free spirals may be up to 40 mm and the diameter, up to 750 mm. Thanks to the high quality of the robust spirals, we produce axle-free spiral conveyors pulling or pushing, conveyors connected perpendicularly (fixing) and vertical axle-free spiral conveyors instead of classic bucket elevators.
The maximum lengths of robust spiral conveyors installed are up to a distance of 55 m according to the transported material type and in cases of vertical transport, about 25 m per drive unit.
Axle-free spiral conveyors are currently replacing the existing classic applications of worm conveyors, bucket elevators, and pneumatic transport more and more frequently. For axle-free spiral conveyors, there is practically no spatial limitation of the transport direction. There are many applications where filling and emptying containers from the horizontal and vertical direction, the transport of materials in technological lines between floors, and transport of high performance at long distances is utilised.
For every industry, we have a corresponding material design of spirals, pipelines, and gutters. The electric gearboxes are supplied in face, screw, helical, and flat designs. Axle-free spirals are supplied in steel of class St 37, St 52 or stainless steel of class (AISI 304, AISI 316, AISI 316L, AISI 316T). For use of conveyors for abrasive materials, spirals are used from the Hardox material of hardness up to 400 Brinell or the axle-free spirals are welded with hard metal or hard metal plates.
Due to the fact that axle-free spiral conveyors are designed and produced by us for many industries (food-processing, chemistry, plastics, energy, heavy industry, agriculture, woodworking industry, ecology, pharmacy, etc.) and these conveyors are made according to our know-how while respecting the requirements of the customer, it is possible to create a spiral or conveyor of the corresponding material and dimensional design upon agreement.
| Type *1 | Outer spiral diameter, mm | Transportation capasity, m3/h *2 |
| STN 60 | 60 | 0,01 – 1,5 |
| ST 60 | 60 | 0,01 – 1,5 |
| STN 80 | 80 | 0,01 – 2,0 |
| ST 80 | 80 | 0,01 – 2,0 |
| ST 100 | 100 | 0,01 – 4,0 |
| STN 100 | 100 | 0,01 – 4,0 |
| ST 110 | 110 | 0,03 – 6,0 |
| ST 120 | 120 | 0,04 – 7,0 |
| STN 120 | 120 | 0,04 – 7,0 |
| ST 140 | 140 | 0,1 – 10,0 |
| STN 140 | 140 | 0,1 – 10,0 |
| ST 160 | 160 | 0,1 – 12,0 |
| STN 160 | 160 | 0,1 – 12,0 |
| ST180 | 180 | 0,3 – 20,0 |
| STN 180 | 180 | 0,3 – 20,0 |
| ST 200 | 200 | 0,5 – 25,0 |
| STN 200 | 200 | 0,5 – 20,0 |
| ST 220 | 220 | 0,5 – 25,0 |
| ST 230 | 230 | 0,5 – 20,0 |
| STN 230 | 230 | 0,5 – 25,0 |
| ST 280 | 280 | 0,5 – 40,0 |
| STN 280 | 280 | 0,5 – 40,0 |
| ST 300 | 300 | 0,5 – 70,0 |
| ST 315 | 315 | 0,5 – 70,0 |
| STN 315 | 315 | 0,5 – 60,0 |
| STN 320 | 320 | 1,0 – 100,0 |
| ST 330 | 330 | 1,0 – 150,0 |
| ST 350 | 350 | 1,0 – 150,0 |
| ST 350/235 | 350 | 1,0 – 100,0 |
| ST 380 | 380 | 3,0 – 200,0 |
| ST 400 | 400 | 3,0 – 200,0 |
| ST 400/265 | 400 | 2,0 – 100,0 |
| STN 400 | 400 | 3,0 – 200,0 |
| ST 450 | 450 | 3,0 – 230,0 |
| ST 460 | 460 | 4,0 – 280,0 |
| ST 500 | 500 | 4,0 – 300,0 |
| ST 520 | 520 | 5,0 – 600,0 |
| ST 600 | 600 | 5,0 – 600,0 |
| STN 600/400 | 600 | 3,0 – 400,0 |
| ST 750/600 | 750 | 20,0 – 500,0 |
Material Design:
Spiral: Type ST – steel (ST 37, ST 52), Type STN – stainless (AISI 302, AISI 304)
Pipeline: Type SL – steel (ST 37, ST 52), Type STN – stainless (AISI 304, AISI 316)
Depending on the type of transported material and specific technological conditions, mutual combinations of designs and other dimensional variants of spirals different from the table above are also used.
*1) Bold marked types – stainless design of the spiral and the pipeline.
*2) Transport performances of individual conveyors depend on the type and physical properties of the transported material.
*3) External diameters of shaftless spiral conveyors depend on the type and physical properties of the transported material.