Condensation Particle Counter

This chapter delves into the condensation particle counter (CPC) technology, providing a comprehensive overview of its key components and functionalities. Section 4.1 introduces and highlights their significance in measuring aerosol particle concentrations. It then proceeds to discuss each component in detail, from the saturator section to the condenser and the optical particle counter. The saturator section (Section 4.2) is a critical part of CPCs responsible for generating a supersaturated gas to suspend fine particles. The structure of the saturator is examined, including its key components, such as the heating pipe, working fluid, and reservoir. The choice of working fluid, particularly n-butanol, and the use of porous media, like silicon carbide and aluminum foam, are explored as means to enhance the gas-liquid interface and optimize saturated working fluid supply. Moreover, a numerical simulation of a designed CPC saturator is presented to analyze its performance. The condenser (Section 4.3) is another vital element of CPCs, where particle condensation occurs to enable detection by the optical particle counter. The structure and operating principles of the condenser segment are discussed in detail. Additionally, a mathematical model for the condenser segment is presented to aid in the determination of design parameters. An illustrative example is provided to demonstrate the process of solving these design parameters. The optical particle counter (Section 4.4) is a key component responsible for counting aerosol particles. Various aspects of the optical particle counter are explored, including the light source, lens, and photodetector. The difference between forward scattering and 90° scattering systems is discussed, along with the concept of single particle counters and multiple particle counters. Calibration technology and error source analysis of CPCs are covered in Section 4.5. The chapter discusses calibration techniques used in CPCs to ensure accurate measurements. An analysis of error sources in CPCs is provided, with a focus on potential factors that may influence measurement accuracy. The section concludes with a summary of the findings. Finally, the chapter concludes with a comparison of different commercial CPCs (Section 4.6). This section evaluates the pros and cons of various CPC models available in the market, aiding researchers and users in selecting the most suitable instrument for their specific applications. This chapter provides a comprehensive and in-depth understanding of CPCs, their core components, and calibration techniques. It serves as a valuable resource for researchers, practitioners, and anyone interested in aerosol particle measurements and characterization using CPC technology.