US Patent 11237091 Humidity conditioning for water-based condensational growth of ultrafine particles

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