Conical screw mixer

Series SF 010 – SB 5000

BOLZ-SUMMIX conical screw mixers and dryers work according to the proven principle of a rotating mixing screw being guided along the wall of the conical vessel at constant close distance by means of an orbital arm. The mixing screw moves through the product and transports it from the bottom of the vessel towards to top. The product is constantly moved upwards along the container wall by the Archimedes-Screw principle.  At the same time gravity pulls the product down along the opposite wall and in the centre, outside the effective range of the mixing screw (convective gravity mixing).. As the rotating orbit arm guides the mixing screw along the wall, a slightly horizontal force results, and thus three-dimensional product flow, giving intense yet gentle mixing.

The gentle mixing is maintained by a displacement of particles against each other by lifting of product by the mixing screw, the imbalanced continuous descending of product in the centre by gravity and the slow radial orbital movement of the arm.

As only a selected, part of the entire batch is mechanically agitated and lifted by the mixing screw, shear applied to the product particles, the resulting wear and attrition, as well as finally the drive power required, are comparatively low and energy saving.

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Technical data

Special properties for the customer’s benefit:

  • Gentle mixing process with low mechanical forces on product like wear/attrition
  • Small drive power without mechanical or thermal product destroyment 
  • High mixing result and efficiency, perfect blending and good mixing time
  • Unique suitability for a wide range of industrial products with various character like density, particle size & shape, proportions etc. without risk of segregation 
  • Maximum flexibility with just partial load from 10 to 100% of nominal batch load without risk of good product quality
  • Well suited for multi-product application & frequently changing product volume
  • A self-supporting mixing screw without lower bearing, with unimpeded, free, central product discharge for optimisation of residue-free discharge with an homogeneous and controllable product flow. 
  • By shimming of the mixing screw contour to vessel and outlet we can minimise the screw-to-wall-clearance and dead space in the bottom
  • A conically expanded “tapered” mixing screw reduces the ineffective zone in the mixer centre, ensures a constant product flow along the entire length of the screw, reduces the mixing time and required drive power, increases product quality and life time of agitated components
  • Good cleanabilty with a complete & residue free drain of cleaning fluids
  • Complete closed process room with high standard of containment
  • Various drive systems in a robust & reliable design for quick&easy maintenance 
  • Not just suitable for dry bulk solids, injection & mixing of liquid fluid is possible
  • Speed-adjustable drives for flexible adaptation to individual applications


Technical data

Usable volume: Completely self-supporting: 100 to 8 000 litres
With radial guidance: 6 000 to 25 000 litres
With bottom bearing: 10 000 to 50 000 litres
  • Good engineering practice, also constructed and tested as a pressure vessel 
  • Simple vessel design or fully welded vessel design suitable for pharmaceutical and sanitary products
  • Internally polished or electro-polished 
  • Externally polished or glassbead-blasted
Variations: Optimised for pharmaceutical, fine chemical or food products
Designed with heating/cooling jacket, solid SS  insulation jacket
  • Add-on components such as vent/exhaust filters, sampling
  • Appropriate discharge/ filling valves (gate, segment valves)
  • A comprehensive range of CIP devices
  • Sprinkling devices of various kinds
  • Instrumentation and process sensors, including PAT
  • Various designs of mixing screw such as the low-hold-up pharmaceutical configuration
  • Available as an individual component or as a total system, including controls
Special design:
  • Large mixer capacities with side discharge and radial guide or lower bearing for the mixing screw
  • Optional bottom driven mixing screw