DEW POINT GENERATOR 10/12/90

摘要

A new type of precision dew point generator has been built at General Eastern Instruments Corp. The dew point generator was designed to be used for testing and calibration of our product (optical chilled mirror dew point instrumentation). The intent of the new design was to upgrade our in house generator from a divided flow system to something with a better theoretical basis. The divided flow system of dew point generation used air which was bubbled through a long column of water to generate a stream of saturated air. Air from a heatless drier passed through a series of molecular sieves was used as a stream of dry air. These two air streams were metered volumetrically and blended together in various volumetric ratios to generate dew points between saturation and the dew point of the dry air. Due to the inaccuracies of the flow meters, no attempt was made to determine an "a priori" dew point from the mixing ratio, but rather the dew point generated was determined using a transfer standard which was calibrated at NIST on a regular basis.