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Fine Separators

KWATANI, previously known as JOEST KWATANI, offers a range of fine screening equipment comprising of round and rectangular separators.

Rectangular R-type and Round S-type Separators – Typical Applications



The bulk density of sugar ranges from 600-800 kg/m3.  Sugar is scalped to remove lumps and foreign material prior to grading or packaging.  There are 2 types of scalping; rough scalping though about 4.75mm and close scalping between 1.0 to 1.7mm.  Very high throughput rates are achievable for rough scalping where capacities can range between 2-35 tph/m2 when close scalping. 

After scalping, grading can be performed in two stages: primary separation and specialty separation.  Primary separation normally produces three grades of sugar: fine granulated, 0.6mm – 1.4mm, 0.18mm – 0.6mm, and fine confectioners’ sugar <0.18mm.  Specialty separation is most often accomplished with a second set of screening machines which have two or more decks fed from the primary separators.  Final product specifications are customer dependent. 

Machine construction is designed to sanitary requirements set out for food products.  


Instant Coffee

Instant or soluble coffee is a granular product with a bulk density of 240-400 kg /m3.  It is screened to remove overs and fines, prior to packaging.

Instant or soluble coffee is scalped through 4.8-2.8mm and fines are removed on 1.0-0.5mm.  Stainless steel screens are most commonly used with a typical loading of 1.8 tph/m2.


Two of the most common types of clay are Bentonite and Kaolin.  Bentonite is used in metal castings, filtering media, pet litter and as a filler element for ceramics, rubber, paper and refractories for the absorption of fluids.  Kaolin has a high fusion point and is used as filler and coating for paper, refractories, ceramics, cements, fertilizer and insecticide.  The bulk density of clay is between 650 to 1300 kg/m3.

In the grinding circuit clay is usually scalped on openings ranging from 10 to 0.85 mm with capacities as high as 18 tph/m2.  Gradings are normally done between 4.75mm and 250 microns and sometimes as fine as 150 micron with a wide range of capacities.

Plastic Pellets

Plastic Pellets are used in making automotive and appliance moulded parts, plastic bottles and coatings for electric wire.  PP Pellets are tablet shaped and PE Pellets are cylindrical.  Particle size is approximately 3 mm in diameter while the bulk density is around 560kg/m3.

In the manufacturing process, PP Pellets are screened after underwater cutting/pelletizing and drying to remove -1 mm fines and +4 mm overs.  Overs consist of clusters of single pellets that adhere to each other as they discharge from the cutter. 

Since the rectangular separator has no vertical component, there is no significant product lost in the oversize fraction because pellets remain fully in contact with the screening surface at all times with no up-ending


Metal Powders

Metal powders such as iron, steel, copper, tin, lead, zinc, nickel and aluminium are screened to provide sized material for a variety of end uses.  Bulk densities vary from 1120 kg/m3 for aluminium to 2560 kg/m3 for iron powder. 

Metal powder separation often requires fine mesh separations in the 100 to 325 mesh range.  Producers require very efficient screening performance to get maximum yield of the accurately sized fractions.  For fine mesh separations, capacities are typically in the range of 50 kg/h – 490 kg/h per m2 of screen area.  Sealing is very important to prevent leakage and contamination between products.  Because metal powders tend to blind fine mesh screens, a mesh cleaning system is critical to provide continuous screening performance.  Constant tensioning of the wire screen is necessary to prevent stretching and sagging of the mesh.



  • Horizontal gyratory motion sifts, rather than forces material through screen
  • Gentle action minimizes screen tears from foreign objects
  • Cleanable sanitary designs
  • Easy disassembly for quick cleanout and low maintenance
  • Totally enclosed - positive sealing
  • Ball mesh cleaning and anti-blinding
  • Cable suspension or floor mounting options
  • Corrosion resistance designs in stainless steel
  • Lower cost designs in mild steel and 3CR12
  • Self-tensioning screen mesh attachment


  • Broad range of product; wet or dry, fine or coarse, heavy or light
  • As many as four screen decks for simultaneous separation into five fractions
  • Less screen blinding
  • High capacity per square meter of screening area when compared with other types of screening devices
  • Smaller footprint with corrosion resistance designs in stainless steel only
  • Simple design providing for less maintenance and less power requirements



KWATANI has a materials testing laboratory to assist you in selecting the correct separator for your application. Here your materials are analysed and tests conducted under simulated production conditions, to help determine the appropriate machine size, optimum screen openings and machine settings for a given application.

Round fine separator
Kwatani stainless steel round separator for fine separation in food processing