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amixon GmbHamixon GmbH

Helix mixing tools

 

Helix mixing tools are also referred to as screw ribbon mixing tools or spiral mixing tools. An outdated term is ‘ribbon’. However, the so-called ribbon blender is a special horizontal screw mixer and therefore not directly comparable with the vertically operating Helix mixers. The terms mentioned usually refer to vertical powder mixers whose mixing tools rotate around a central vertical axis.

These mixers belong to the category of precision mixers. They produce technically ideal mixing qualities for dry, moist and suspended solids. The mixing chamber typically consists of a vertical cylinder closed at the top and bottom by a head plate and a base plate. Inside the cylinder is the helical mixing tool, which is mounted along the axis of symmetry of the mixing chamber.

In amixon® mixers, the mixing tool is mounted exclusively at the top. There are no shaft bushings or bearings in the area of the base plate. Filling takes place from above and emptying from below. Appropriate fittings and valves are provided for this purpose.

In addition to the classic helix geometry, amixon® also manufactures special designs of mixing spirals, which are known as SinConvex® and SinConcave®. These special designs improve mixing efficiency, especially for difficult-to-mix material systems, while also promoting the self-emptying effect of the mixer. They help to reduce product residues to a minimum and facilitate cleaning of the mixing chamber.

The axial conveying capacity of a helix mixing tool can be calculated approximately using the following formula:

 

IV=π/4⋅(D2−d2)⋅φ⋅S⋅n⋅ζ

 

Where:

  • IV: Conveying volume flow
  • π: Circle constant (approx. 3{,}1416)
  • D: Outer diameter of the mixing helix
  • d: Inner diameter of the mixing helix
  • φ: Filling degree (dimensionless value between 0 and 1)
  • S: Pitch of the helix
  • n: Rotational frequency of the helix (revolutions per second)
  • ζ: Speed coefficient (dimensionless, based on experience)

The formula describes the theoretical flow rate per unit of time that a helical mixing tool can move upwards within the rotationally symmetrical mixing chamber.