Shaftless inclined tube conveyor

4 pcs. shaftless inclined tube conveyor manufactured for removing rock waste in a biogas plant. The minor rock parts are removed from the process, and the shaftless tube conveyor transport them and dump it into a small container.

Shaftless screw conveyors have certain advantages to be noted:

1. They are non-clogging and are specially suitable for sticky material
2. In this case they are also good to handle rock waste within the size of the screw rotor
3. For longer conveyors you avoid to think about intermediate bearings

When using shaftless screw conveyors, the speed of the screw rotor has to be relatively low – typically below 30 RPM. If the transport requires a high volume flow in combination with a speed above 50 RPM, the shaftless screw conveyor is not a stable solution. In such case you shall use a conventional screw conveyor with an inner pipe.

Features of these shaftless screw conveyors

• They are made with precise connection point, to fit together with exsisting equipment on site
• They have been tested over a long time period to verify that they are suitable for rock waste

BEMA has production capability to manufacture shaftless screw conveyors as well as conventional screw conveyors with an inner pipe. Our engineers and designers can assist you in selecting the most optimal solution for your application.

See another example of a shaftless tube conveyor here

What is the most commonly used material for shaftless screw conveyors?

• Carbon steel – 1.0570/S-355
• Stainless steel – 1.4301/1.4401 AISI-304/AISI-316
• Hardox steel

BEMA has developed efficient method for handling Hardox and other hardened steel types for manufacturing screw flights:

• Cylindridal flight segments
• Shaftless screw flights

If you have abrasive materials to be transported these type of steel will increase the lifte time of the application.

BEMA can always assist you with advise when you evaluate which type of screw flight you want to use for  your application – shaftless type or a conventional screw rotor with flight segments welded to an inner pipe.

FAQ – Shaftless Inclined Tube Conveyor

1. What are the main advantages of a shaftless screw conveyor?

A shaftless screw conveyor is ideal for sticky, irregular or difficult materials because it is non‑clogging and operates without an inner shaft. This design reduces the risk of blockages and eliminates the need for intermediate bearings on longer conveyors, making the system simpler, more reliable and easier to maintain .

2. When is a shaftless conveyor not the right solution?

If the application requires high capacity at speeds above 50 RPM, a shaftless screw conveyor becomes unstable. In such cases, a conventional screw conveyor with an inner pipe is the recommended solution, as it provides better stability at higher rotational speeds .

3. What materials are commonly used for shaftless screw conveyors?

Typical materials include carbon steel (S‑355), stainless steel (AISI 304/316) and Hardox. Hardox and other hardened steels are especially beneficial for abrasive materials, as they significantly increase the lifetime of the screw flights and overall system durability .

4. Can BEMA assist with selecting the right conveyor type?

Yes. BEMA’s engineers and designers help evaluate whether a shaftless or conventional screw conveyor is the optimal choice. They also ensure precise connection points, compatibility with existing equipment and long‑term performance through testing and tailored design support.