Development of a Dew-Point Generator for Gases Other than Air and Nitrogen and Pressures up to 6 MPa

Abstract

A new primary humidity standard is currently being developed at VSL that, in addition to ordinary operation with air and nitrogen at atmospheric pressure, can be operated also with special carrier gases such as natural gas and SF6 and at pressures up to 6 MPa. In this paper, the design and construction of this new primary dew-point generator and the preliminary tests performed on the generator are reported. The results of the first efficiency tests, performed for the dew-point temperature range from −50 °C to 20°C, for pressures up to 0.7MPa and for carrier gas flow rates up to 4L· min−1, showed satisfactory generator performance when used in the single-pass mode, i.e., with no recirculation of the carrier gas.