Extrudomix medium pressure extruder

The Extrudomix is an efficient horizontal medium pressure kneader/extruder that generates uniform free-flowing pellets and extrudates. It will accept plastic masses or generate its own with continuous internal mixing of solids and lubricants prior to extrusion.

It is also useful following batch premixers or for premixing ahead of batch equipment. Dry materials may be thoroughly mixed and extruded with relatively small quantitites of liquids for agglomeration, or relatively large amounts of liquids for producing pasty masses.

Extrudomix medium pressure extruder


The Extrudomix has a single horizontal shaft, carrying rows of hammers arranged in a spiral pattern that moves the material through the chamber. Stationary anvils attached to the housing are inserted between the rotating hammers.

Material is fed into the housing at one end and forced forward by the rotating hammer until it comes in contact with the stationary anvil. The action of the anvil prevents the material from rotating with the shaft. Thus, the effect of the unit is to give a continuous kneading and mixing action on materials. The special designed shaft assembly is giving positive displacement to the product which is conveyed in direction of the outlet. A perforated orifice plate of various shapes and sizes can be used to extrude material into various sizes and shapes.

Due to the medium shear treatment of the product, the products extruded by the Extrudomix have good particle dispersibility.

The Extrudomix is used for extrusion, kneading and mixing. During processing, the unit can be heated or cooled using the jacket. The unit can work as standalone unit or in combination with other process equipment.

The Extrudomix is available in sizes ranging from 150 mm to 600 mm inner housing diameter and for throughputs of up to 5 tons per hour with drive units up to 160 kW.

With the compactness of the design a very minimal amount of floor space and head room is required. Sizing for a specific application is based on the process parameters during the tests with product in our test facilities.

Process considerations

Processing influences can be broken down into two major areas. Those primarily attributable to the mechanical design and those dictated more by the raw materials and final product characteristics. Of course, each influences the other and many designs are dictated by a particular material’s characteristic.

Material Conveyance

During the process of conveying the material toward the discharge die plate, the liquid binder is mixed onto the surfaces of the solid material. Particle size, bulk density, product tackiness, and rotor speeds all have influences on the conveyance of the material.

Material Heat Sensitivity

Heat sensitivity dictates special considerations in the design of the Extrudomix. Standard options that are available to dissipate heat include 1) a cooling jacket on the body, 2) boring the rotor shaft for circulation of cooling media, 3) use of larger orifice plates, and 4) reduced operating speed. Heat sensitivity results in a conflict between the removal of the heat and the mechanical energy necessary to extrude the material. Product formulation can be modified to add a higher level of binder to increase the lubrication and decrease the energy necessary for extrusion.

Orifice Plate design

The Extrudomix can be designed with as many as three orifice plates, and as few as one. Orifice plates can be located in two positions internally in the closed section of the body, and at the discharge end. Internal orifice plates are sized for each application. They are used to constrict the conveyance and, therefore, increase the amount of mixing of product and binder. The end orifice plate is the final control of the amount of mixing of product and binder and determines the final product size. Factors such as plate thickness, total open area, hole size and the length to diameter ratio are major considerations in determining the proper end plate design.

Binder Selection

The type of binder used has an influence on the design and process. The most common type of binding system is aqueous with the possible addition of surfactants for wetting. Melt binding systems are also used with the binder added in molten or powdered form. The melt system depends on the mechanically generated heat of extrusion to melt the binding system. Solutions, slurries, waxes; oils are also common binders and lubricants.

Applications

The Extrudomix is used for the formation of cylindrical pellets with diameters ranging from 2.0 to 6.0 mm where good dispersion and a dust free particle is desired. Rubber and plastic additives, detergent formulations, sugars, yeast and pigments are typical applications.

Many organic chemical additives, which are handled in a dry form, require fine grinding to obtain the required reactivity. This is especially true in non-solvent mechanically dispersed systems. Because of the small particle size, the material is very dusty and, depending on the nature of the material, may pose a health risk. Transformation in a dust free product is therefore required.

Examples

  • Extrusion and forming of fresh yeast preceding fluid bed drying
  • Agglomerating simple sugars to improve feed attributes for filling and tabletting operations
  • Production of readily dispersible food ingredient granules
  • De-agglomeration, mixing and extrusion of waste/scrap soap
  • Intimate dispersion of various pigment agents to provide uniform blend
  • Transformation of filter cake into dry-able pellets
  • Pelletizing of CMC filter cake
  • Blending potato flakes, water and others into a dough
  • Formation of granular Lysine
  • Densification and pelletizing of pectin prior to drying
  • Transformation of powder with liquid into doughy mass
  • Pre-processing and extrusion prior to spheronisation or drying

 

  • Medium shear mixing
  • Mixing and extrusion in one machine
  • Compact design including heating / cooling jacket
  • Excellent mixing performance
  • Multiple static and rotating elements securing continuous kneeding
  • Capacity from 50 kg/h up to 5000 kg/h

The Extrodumix medium pressure extruder is available in several models. Here we listed 5 models with their basic characteristics:

Model [-] EM-6 EM-10 EM-12 EM-15 EM-24
Approx. capacity [kg/h] 340 680 1140 1820 4550
Typical motor power [kW] 7.5 - 18.5 15 - 37 37 - 55 55 - 90 90 - 160
Shaft speed [r/min] 50 - 440 50 - 300 50 - 260 50 - 220 50 - 150

How can we help you?

If you want to learn more about our powder process equipment, call us at +31 314 373 333 or fill out our inquiry form.

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