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General Purpose Water-based Condensation Particle Counter 3787

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Product Details

TSI's Model 3787 General Purpose Water-based Condensation Particle Counter (GP-WCPC) can detect airborne particles down to 5 nm in diameter using state-of-the-art, water-based condensation particle counting technology. With a high sample flow rate of 0.6 LPM, the versatile Model 3787 is a good choice for low concentration measurements, yet it is also capable of measuring up to 250,000 particles/cm 3 using exclusively single particle counting. The carefully designed flow path, high flow rate, and sophisticated electronics used in the Model 3787 result in a rise time of < 1 3 second.

This utilitarian instrument can be employed as a stand-alone counter or it can be used as a component of a TSI SMPS ™  spectrometer , a submicron sizing system.

Features and Benefits

  • 5 nanometer detection
  • < 300 millisecond rise time response
  • High aerosol flow rate for enhanced counting statistics
  • Convenient, eco-friendly water as working fluid 110 th second data reporting
  • Built-in SMPS™ spectrometer compatibility
  • 6" color touch screen with graphical interface
  • USB flash drive data storage option
  • Built in Ethernet capability
  • Advanced instrument diagnostics


The GP-WCPC Model 3787 is suitable for many particle-counting applications due to its comprehensive set of specifications, but the convenience of using water for the measurement of submicron particles makes it well suited for:

  • Indoor research applications
  • Ambient air research
  • Inhalation or exposure chamber studies
  • Health effects studies

Learn how to purchase a GP-WCPC Model 3787 for less !


  • Can the CPC be operated with different carrier gases?
    Yes, but only inert gases.
  • How does the water CPC performance compare to CPCs that use butanol?
    Laboratory and field tests show excellent agreement and correlation between the water CPC (Model 3785) and butanol CPCs (Models 3010, 3025A and 3022A) for particles larger than about 20–30 nm. Preliminary test results can be viewed in a poster presentation by S. Hering, M. Stolzenburg, F. Quant and D. Oberreit (2003 AAAR Annual Conference, Anaheim, CA) at Additional test data will soon be submitted for publication.
  • How frequently should I have the CPC serviced?
    We recommend the CPC be returned for annual maintenance service. Your company’s Quality Management System may specify a more or less frequent service interval based on history, use and criticality of the measurement. The Standard Annual Service includes:Perform an ‘AS FOUND’ operational and calibration check.Replace tubing, o-rings and water wick.Clean optics, flow path and all wetted parts.Update firmware/software.Perform operational check.Calibrate flows.Calibrate photometric mode using sodium chloride aerosol.
  • How pure does the water need to be?
    We recommend using water that is distilled or purer. 
  • How sensitive is the instrument to flooding?
    While fairly insensitive to flooding, several precautionary measures will help avoid this condition. Do not tip the instrument more than 10 degrees in any direction. Avoid large pressure fluctuations or restrictions in flow at the sample inlet (>25 cm water at 1.0 liter/minute). When accessing the reservoir for cleaning or drying, always lay the instrument on its side with the Fill and Drain connectors on the bottom. 
  • Is the counting efficiency for each CPC determined individually?
    No. The CPC efficiency curve has been determined by testing a statistically valid number of CPCs and averaging the results to obtain the curve published in the product literature. Variation between units is very small. 
  • What is the final droplet size after growth by condensation?
    This question has been investigated, theoretically, by Ahn and Liu (1990). For the initial particle diameters of 5 and 20 nm, the computation results show a final droplet size of 11.3 and 12.3 micrometers, respectively (Ahn and Liu, 1990). Similar experimental results have also been determined.

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