Condensation nucleus counter using mixing and cooling

A condensation nuclei counter comprising:

• a saturator chamber maintained at a first temperature and containing a working fluid such that a gas flowing through said saturator chamber becomes saturated with respect to said working fluid to form a saturated gas;
• heating means for maintaining said saturator chamber at said first temperature;
• a growth chamber for producing a supersaturation condition therein with respect to said working fluid, having a first inlet connected to an outlet of said saturator chamber for receiving said saturated gas and a second inlet for receiving a sample gas at a temperature less than said first temperature, said sample gas having particles entrained therein upon which said working fluid condenses to produce enlarged particles;
• cooling means for cooling an interior of said growth chamber whereby a gas mixture of said saturated gas and said sample gas is cooled to a mixture temperature that is less than said first temperature;
• light scattering particle detection means for receiving said enlarged particles from said growth chamber and sensing a characteristic of said enlarged particles;
• and
• differential pressure means for causing said saturated gas and said sample gas to flow into said condensation nuclei counter.

A method of operating a condensation nuclei counter for counting a number of particles, comprising the steps of:

• saturating a gas flow at a first temperature with a working fluid to produce a saturated gas flow;
• filtering said saturated gas flow to remove particles from said saturated gas flow;
• cooling a growth chamber within which said saturated gas and a sample gas having said particles entrained therein are mixed;
• growing a plurality of enlarged particles within said growth chamber using said particles as nucleation sites for condensation;
• and
• counting a number of enlarged particles with a light scattering particle detection means.