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picojet - fluidised bed opposed jet mill

The picojet is a fluidised bed opposed jet mill with integrated classifier for the low contamination dry ultrafine milling of middle hard to hard materials. The design and principle of operation are almost identical with that of  Alpine's AFG product line of fluidised bed opposed jet mills.

For the contamination-free ultrafine comminution with integrated classification of materials with a Mohs’ hardness of up to 10. The mill produces powders with a steep particle size distribution and sharp top cut in the fineness range 2 µm — 120 µm.

  • Principle

    The grinding energy in the form of highly accelerated air jets enters the mill via three nozzles. The feed material is dosed into the grinding chamber and is fluidised by the air jets. The particles are accelerated in the air jets, which intersect at the focal point. Comminution is a result of the particles impacting in the focal point and of shear flows in the peripheral zone of the air jets.

    The grinding air then flows through the classifying wheel located in the mill head and the product is classified. Fine particles exit the mill through the classifying wheel entrained in the air and are collected in a filter. Coarser particles fall back into the fluidised bed and are comminuted further until they have reached the desired fineness. The fineness is set as a function of the air flow rate, the grinding air pressure and the classifying wheel speed.

  • Features
    • Operation with compressed air and/or inert gas
    • Either batch or continuous operation
    • Material feed from above at the classifier head
    • Nozzles integrated into the housing insert
    • Classifying wheel gap and motor bearing rinsed with gas
    • Classifying wheel gap easy to adjust
    • Grinding and rinsing air supplied through the platform adapter (no tubes)
  • Technical specification
    Grinding chamber diameter:40 mm
    Classifying wheel diameter:20 mm
    Classifier speed:max. 60,000 1/min
    Total air flow rate:20 Nm³/h
    Milling air pressure:2 - 6.5 bar (g)
    Minimum batch size in batch operation:ca. 5 g
    Max. feed size:500 µm
  • Variants
    • Wear-protected design
    • Horizontal nozzle arrangement
    • 3D nozzle arrangement


Mr. M  Schoenwetter:
Tel.: + 49 821 5906-484

Ms. N. Boeck:
Tel.: + 49 821 5906-485 

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