Volume 33, Issue 2 (March 2005)
Optimum Design of Gas Pycnometers for Determining the Volume of Solid Particles
Gas pycnometry is based on Boyle-Mariotte's law. There are three kinds of gas pycnometers reported in the literature: “constant-volume,” “variable-volume,” and “comparative.” These instruments are widely used to determine the volume—and thus the density—of granular, porous, or soluble compounds (e.g., rocks, coal, pigments, ceramic, drugs, seeds). However, many users do not know the optimum-use conditions of their gas pycnometer. This work provides a synthesis of recent studies about the optimum design of the gas pycnometers. It seems possible to use commercially available components for constructing gas pycnometers that can determine the volume of solid particles with a relative standard uncertainty smaller than 0.25 %. Compared to other gas pycnometers, the constant-volume pycnometer presents several practical advantages.