FIELD

The technology pertains to the measurement of particles suspended in air or other gas.

BACKGROUND

For many decades particle condensation methods have been used to enable the detection, or collection of submicrometer-sized particles suspended in air or other gas. More recently, condensational growth has also been applied to aerodynamics focusing, or to enhance the electrical charging of these ultrafine particles. Condensational growth is used because individual gas-borne particles smaller than about 100 nm are difficult to detect optically and are difficult to manipulate by inertial means. Condensation has been used to enlarge particles as small as a few nanometers, or a few tens of nanometers in diameter, to form micrometer sized droplets, which are then detected optically, collected inertially, or otherwise manipulated.

For water condensation systems used in particle counters, it is advantageous to condition the flow to a moderately high, or high relative humidity prior to measurement.

SUMMARY

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

One general aspect includes a particle growth apparatus. The apparatus includes a temperature-controlled humidifier coupled to a water-based condensation growth system. The humidifier may include a tube which may comprise sulfonated tetrafluoroethylene-based fluoropolymer-copolymer and may be surrounded by a region containing water or water vapor. The apparatus also includes a wetted wick and wick sensor in the condensation growth system. The apparatus also includes the humidifier configured such that the gas sample flows through the sulfonated tetrafluoroethylene-based fluoropolymer-copolymer tube into the condensation growth system.

Another aspect of the technology is an apparatus including a humidifier coupled to a water-based condensation growth system. The humidifier may include a tube comprising sulfonated tetrafluoroethylene-based fluoropolymer-copolymer surrounded by a region containing wetted crystals of polyacrylate salt. A gas sample flows through the sulfonated tetrafluoroethylene-based fluoropolymer-copolymer tube into the condensation growth system.

