Dosing screw conveyor combined with mixing

The dosing screw conveyor was designed to sit under a silo containing salt to be mixed with an additive. The dosing screw should control the flow from the sile, and the paddle mix the material.

Key points for function

• The screw is placed beneath a silo
• In the dosing part iodine is added to the salt
• In the mixing part (with paddle flights), the iodine is mixed into the salt and transported to the outlet
• Adjustable legs for easy mount on site

What happened with the dosing screw conveyor combination?

The salt from the bin overfloded the screw conveyor and the mixing part was unable to mix it properly.

Lessons learned

1. Be very careful to combine 2 different functions in a screw conveyor. Specially a dosing screw conveyor, where you need to control the flow
2. If this function do not work properly the other function of the mixing screw conveyor will not work
3. If you have a problem with one function, you cannot change it without changing the other functions. The 2 functions are not independant!

As a general rule you shall not combine functions in dosing screw conveyors. The ideas to save quick money will end up that you in the best case can utilize on function of the dosing screw conveyor. In the actual case the customer ended up using the screw conveyor as a pulling screw conveyor from a salt silo. At least the combined screw conveyor could be used, but we all learned from this experience. See an example of dosing screw conveyor See an example of a mixing screw conveyor

FAQ: Dosing Screw Conveyor Combined With Mixing

1. What is a dosing screw conveyor with integrated mixing?

A dosing screw conveyor with mixing combines two functions in one unit: controlled dosing of material from a silo and mechanical mixing using paddle flights. In this setup, the screw regulates the material flow, while the mixing section blends additives—such as iodine—into the main product before discharge.

2. When is this type of combined solution typically used?

It is commonly used when a material, such as salt, must be dosed precisely and mixed with an additive during transport. The system is placed directly beneath a silo, making it suitable for continuous processing environments where dosing accuracy and homogeneity are essential.

3. What challenges can occur when combining dosing and mixing in one screw conveyor?

If the dosing function does not regulate flow correctly, the mixing section may become overloaded. This can prevent proper blending and reduce overall performance. In the referenced case, excess salt from the silo overwhelmed the screw, making effective mixing impossible.

4. Why is it risky to combine two functions in a single screw conveyor?

Dosing and mixing rely on different operating conditions. If one function fails or needs adjustment, the other is affected as well. Because the functions are not independent, troubleshooting becomes more complex and may require redesigning the entire unit.

5. What was the final outcome in this specific project?

The customer ultimately used the unit only as a pulling screw conveyor from the salt silo. Although the combined concept did not work as intended, the experience provided valuable insights into why dosing and mixing should generally remain separate.