Water-based CPCs deliver accurate concentrations of particles in gases while making use of safe, eco-friendly and easily available distilled water. When combined with a particle sizer, nanoparticle size distributions and concentration can be quantified from <2 nm to nearly 1,000 nm.

The 3rd generation of water-based CPC comes with numerous enhancements:
+ Unprecedented reliability
+ Low maintenance
+ Selectable cut-off particle size




Our customers rely on constant operation of the Versatile Water-Based Condensation Particle Counter under many different conditions. The 3rd generation of W-CPC from TSI is robust by design.3789 Interior diagram of Versatile Water-Based Condensation Particle Counter

Micro-pumps control the water injection into the wick and the ejection of excess water from the wick. Controlling both of these flows prevents the accumulation of excess water inside the instrument, even in the case of a blocked inlet.

The condensation process has been extended by a 3rd step. Following the inlet:

  1. The aerosol is conditioned in a cooled, humid environment.
  2. Heat forces water vapor to supersaturate in the centerline of the flowpath, and initiates condensation on the nanoparticles.
  3. Cooling down, the condensation process is concluded. Excess water vapor is condensed, preventing water condensation in subsequent parts of the instrument. This condensed water flows back into the lower portions of the wick for reuse.

All three stages are connected by a single newly designed wick which serves as the water reservoir.

These features make the new Versatile Water-based CPC very resistant to pressure changes occurring in some experimental setups. The following stress test shows that the 3789 recovers rapidly from extreme and frequent pressure fluctuations, returning quickly to making accurate measurements. In the test, the CPC inlet was temporarily blocked over 1,000 times, simulating extreme pressure fluctuations. The concentration readings dropped during the blockage of the sampling flow as expected. After the blockage was removed, the concentrations recovered quickly to the same level as the undisturbed reference CPC.

3789 Relative Concentration Chart


While the wick serves as the water reservoir, a stagnant reservoir can quickly become contaminated with microbial growth. This degrades the wick and compromises data quality. To resolve this problem, the design of the 3789 uses a slight amount of excess water to flush the wick. This regenerates the wick material and extends the wick life-time to 6 months of operation time and beyond.


New to Condensation Particle Counter technology is the ability of this V-WCPC 3789 to enable the user to easily vary the counting efficiency of the instrument. The user interface provides the choice of setting the 50% counting efficiency to 2.2 nm, 7 nm, or to a custom setting. The pre-defined efficiency setpoints are valid for sucrose and characterized at TSI.

For the first time, the skilled researcher can choose different setpoints to vary the cut-off particle size, even outside the settings predefined by the manufacturer. With appropriate instrumentation, it is possible to detect particle sizes near 1 nm.*


TSI’s Versatile Water-based CPC is suitable for most particle counting applications, but its ability to detect down to 2.2 nanometers make this Water-based CPC ideally suited for:

  • Particle formation and growth studies
  • Nanotechnology research or process monitoring
  • Inhalation or exposure chamber studies
  • Long-term, uninterrupted air quality monitoring


* Source: Susanne V. Hering, Gregory S. Lewis, Steven R. Spielman, Arantzazu Eiguren-Fernandez, Nathan M. Kreisberg, Chongai Kuang & Michel Attoui (2017) Detection near 1-nm with a laminar-flow, water-based condensation particle counter, Aerosol Science and Technology, 51:3, 354-362.



  • Selectable cut-off particle size
  • Predefined setpoints of 50% counting efficiency for 2.2 nm and 7 nm (sucrose)
  • Custom setting memory for user-defined counting efficiency
  • Single particle counting up to 2 x 105 particles/cm³
  • Distilled water as convenient, eco-friendly and safe working fluid
  • 50 Hz data acquisition
  • Built-in SMPS™ spectrometer compatibility
  • Large internal memory for 1+ year of data
  • Remote control and data download through Ethernet

Brošure i tehničke specifikacije

Versatile Water-Based CPC 3789 Brochure A4

Particle Instruments Catalog US

Versatile Water-based Condensation Particle Counter 3789 Poster

Water-based Condensation Particle Counter 3789 Spec Sheet A4