COLD TRAP

PURPOSE:To prevent the clogging of orifices, by providing a heating means to a gas jet pipe having a plurality of orifices. CONSTITUTION:A gaseous mixture 1 is introduced into a jet pipe 12 from a gaseous mixture inlet nozzle 2 and injected from orifices 11 and sprayed to cooling fns to be condensed and adhered thereto. A heating medium is introduced into a round pipe 13A to be flowed through the gap between an inner pipe 13A and an outer pipe 13B and discharged from an outlet 13C while the gaseous mixture is heated by said heating medium 13 to prevent the condensation of condensible gas.