A new apparatus for measurements of PVT properties and their derivatives with a metal bellows was designed for fluids and fluid mixtures of a fixed composition for pressures up to 20 MPa in the range of temperatures from room-temperature condition to 473 K. The apparatus, procedures, and results of calibrations are described. The capabilities of the apparatus are illustrated by means of the vapor-pressure measurements for chlorodifluoromethane and the PVT measurements of sulfur hexafluoride. Temperatures were set and kept constant at the values desired within ±3 mK and pressures within ±2 kPa. It was shown that density derivatives with respect to pressure at constant temperature and those with respect to temperature at constant pressure may both obtain from the experimental results.
All Science Journal Classification (ASJC) codes