Alpine Circoplex ZPS

The Alpine ZPS air classifying mill is a high-speed impact mill that offers grinding and classifying in one single machine. Rejection of coarse material occurs totally inside the mill by means of a positive material and air transport system. This feature combined with a horizontally oriented classifier offers the following distinct design advantages in bulk pharmaceutical milling:

  • Two step processes combined in one machine
  • Monoblock construction CNC machined from one piece of stainless steel
  • Steep resultant particle size distributions
  • Sharp classifier top cuts, instantly adjustable
  • Easy clean CIP designs available
  • Low grinding temperature for heat sensitive material
  • Sterilize in Place (SIP) designs also available through the unique design retractable bearing assembly

Soft to medium hard products, such as pharmaceuticals , can be reduced to D97 as low as 10 microns with steep overall particle size distributions.

As indicated in this schematic, most of the process gas enters through the bottom section of the mill. Material is introduced to the tip of the rotating hammers through a port opening in the side of the mill. A serrated liner mounted on the periphery of the grinding chamber prevents particles from speeding directly to the hammers. After being impacted by the hammers of the grinding ring, reduced material is introduced to the classifier wheel. Depending upon the air flow rate and the classifier speed, material either passes through the classifier wheel or is rejected and sent back down in the grinding zone. By adjusting both the speed of the classifier and the rotor, precise control can be maintained on both the D50 and the D90 of the resultant particle size distribution.

The ZPS is available in a variety of designs dependent upon the overall system requirements. These design options include the following:

  • Pressure Shock Resistant to 11 bar.
  • Fabricated housings available in surface finishes as high as 0.2 micron Ra
  • Inert gas operation, either once through nitrogen flow or closed loop operation
  • Interchangeable with Alpine AFG micronizer design for two mill types in one unit

Mill sizes are available anywhere from 1/2 HP to 15 HP for pharmaceutical batch design.

Alpine ZPS air classifier mills can also be integrated into Stott Isolators. This arrangement provides a completely integrated system capable of containment levels as low as 1 microgram/cubic meter.

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