The moisture is evaporated from the surface of temperature raised liquid droplet.
The overheated steam around is cooled and temperature gets down when moisture is evaporated at this time.
The approaching temperature becomes the saturation temperature at the degree of vacuum in evaporator.
The liquid droplet will be dry powder with time but the temperature of article is not raised above saturation temperature at the degree of vacuum in evaporator as far as moisture is remained even a little.
The raw material which became dry powder after moisture evaporation keeps up a stream of steam with saturated temperature and is collected by cyclone separator.