Generation of Test Atmospheres from a Vapor Pressure Saturator

摘要

A method to generate a saturated vapor at a known temperature into the air was developed for testing the accuracy of air sampling instruments. This vapor pressure saturated system consists of a permanent gas into which an amount of volatile liquid is evaporated. The ambient saturator is filled with solvent to a concentration above the air entrance so that the air bubbles through 5 to 10 centimeters of solvent. After the diluent gas at a given temperature is saturated, it is cooled in the ice point saturator to a lower constant temperature, and the excess contaminant is condensed out, leaving the gas mixture saturated at a lower temperature. The effective vapor pressure of the contaminant depends upon the mole percentage of contaminant in the mixture.