Tel: +31 (0)162 460404
CPS Instruments - Worlds leading Disc Centrifuge Manufacturer

Disc Centrifuge

The CPS Disc Centrifuge is a complete, high resolution particle size analysis system for measuring particles in the size range of ~0.005 micron to ~75 microns.

  • General Principle of Operation
  • Size Range Capability
  • Analysis Time
  • Applications
  • Advantages
  • Standard configuration and options

    CPS Disc Centrifuge DC24000

    General Principle of Operation

    The CPS Disc Centrifuge separates particles by size using centrifugal sedimentation in a liquid medium. The sedimentation is stabilized by a slight density gradient within the liquid.

    Front view of the disc
    Front view of the disc

    The particles sediment within an optically clear, rotating disc. When particles approach the outside edge of the rotating disc, they block/scatter a portion of a light beam that passes through the disc. The change in light intensity is continuously recorded, and converted by the operating software into a particle size distribution.

    Cross section view of the disc
    Cross section view of the disc

    Size Range Capability

    The practical measurement range in any application depends upon the density of the particles to be measured. With very dense particles (for example, 6 times the density of water) the maximum and minimum sizes are smaller (~10 microns to under 0.005 micron). With low density particles (for example, from 0.85 g/cc to 1.10 g/cc) the maximum and minimum sizes are larger (~75 microns to ~0.02 micron). The practical dynamic range (ratio of largest to smallest sizes) in a single analysis is about 70 using fixed centrifuge speed, and up to 1000 using ramping of speed during the analysis. For fixed speed, if the largest particle to be measured is 3 microns, then particles as small as 0.02 micron can normally be measured in a single analysis of less than 1 hour. For ramped speed, if the largest particle to be measured is 10 microns, then particles less than 0.02 micron could normally be measured in a single run. The maximum speed of the disc is 12,000 RPM for the Model DC12000 (larger minimum particle size), and 18,000 RPM for the Model DC18000 (smaller minimum particle size), and 24,000 RPM for the Model DC24000UHR (smallest minimum particle size).

    Analysis Time

    Analysis time will depend upon the range of sizes that is being analyzed and the density of the particles being measured. For a majority of applications, analysis times are in the range of 3 to 15 minutes for each sample. For extremely fine particles (0.005 to 0.06 micron), the analysis time can reach 30 minutes or more. CPS has developed techniques to allow analysis of most types of very small particles in a reasonable time. We can measure the size distribution of one or more samples to determine the exact analysis time in your application.


    Here are a few of the many applications where the CPS Disc Centrifuge can be used:

    • Chemical:

      • Polymer latexes and emulsions
      • Fillers (CaCO3, clay, barites, etc.)
      • SiO2 dispersions
      • Abrasives (of all types)
      • Impact modifier particles
      • Oil emulsions

    • Pharmaceutical:

      • Virus particles/virus-like particles
      • Cells (culture) and cell fragments
      • Protein clusters
      • Liposome's
      • Particles in diagnostic tests
      • Micro-encapsulated drugs

    • Semiconductor:

      • Micro-abrasives
      • CMP compounds for integrated circuits

    • Printing and painting:

      • Pigments - water and oil based
      • Micro-fiber paint viscosity modifiers
      • Printer/copier toner powders
      • Inkjet inks
      • Carbon black
      • Magnetic iron oxide

    • Others:

      • Micro-spheres
      • Agglomeration patterns
      • Starch/flour particles
    Visit the CPS Technical Library, where you can download documents on particle size analysis in .PDF format, ranging from promotional literature to application notes.


    • Extremely high resolution compared to methods based on light scattering or particle counting, with clean separation of narrow peaks that differ in size by as little as 2%. The instrument resolution is so high that the reported size ditribution contains almost no contribution from the instrument: you see the distribution itself, not a mixture of distribtuion and the instrument.
    • Very high sensitivity, with a minimum detection limit below 10-8 gram active sample for narrow peaks. Analysis of samples of a few micrograms active weight is routine.
    • Highly reproducible results; the typical 95% confidence range for reported peak sizes in replicate analyses is +/-1% or better.
    • Continuous centrifuge operation; no need to stop and clean the centrifuge between samples. Analyses require a minimum of operator labor.
    • Much faster analyses than with competitive sedimentation based particle sizing instruments. If you have used other centrifugal particle sizing instruments, then you will be surprised by the analysis speed of the CPS Disc Centrifuge; all fixed speed analyses run in 1/3 to 1/6 of the time required on other centrifugal instruments. This speed advantage comes from much higher maximum speed and much faster instrument detector response. With speed ramping, analyses can take less than 1/20 as long. In many applications, run-to-run analysis time approaches analyses based on light scattering.
    • Absolute measurement accuracy limited only by the accuracy of the calibration standard used. Internal or external calibration methods can be used.
    • Measurement of particles of virtually any density, including those equal to or less than the density of the fluid in which they are suspended, using a unique analysis method developed by CPS (US Patent 5,786,898).
    • Completely graphical operating software with simple point-and-click commands, including centrifuge speed.
    • Optional automatic density gradient builder for rapid and accurate filling of the centrifuge chamber.
    • Optional Autosampler for unattended operation; up to a total of 20 samples and calibration standards.
    • Wide range of presentation options, including multiple distribution overlays, linear or log scaling, averaging of multiple distributions, subtraction of one distribution from another, and many more.
    • Rugged reliable construction.
    • No scheduled maintenance, >20,000 hours projected motor life.
    • Two years free software updates.
    Each Disc Centrifuge configuration includes standard:

    • Disc Centrifuge with a 405 nm light-source/detector

      Light-source/detector with disc

    • On-board computer with operating software
    • User Manual
    • Two Calibration Standards
    • Start up set for density gradient
    • Unlimited e-mail and telephone support

    • Disc for Low Density particles
    • Disc option for Speed Ramping

      CPS Density Gradient Builder          CPS Automatic Sample Injection System

    • Density Gradient Builder
    • Automatic Sample Injection System