How manual dew point measurement carried out by surveyors when monitoring the dryness of a cargo tank prior to loading?
A small quantity of Acetone is placed into the device and dry-ice is progressively added to it to steadily reduce the temperature.A sample of the atmosphere in the tank is continuously drawn through the device,passing over the polished or mirrored surface of the container.When the first drop of mositure(dew) is observed to form on the polished surface,the temperature of the Acetone bath is noted.Reference may be required to tables to correct the reading for desired parameters.
