Kyung-Ho Chang, Yong-Jae Lee
VOLUME MEASUREMENT OF 1 kg WEIGHT BY HYDROSTATIC WEIGHING USING TWO ZERODUR DENSITY STANDARD SPHERES
The hydrostatic weighing apparatus using two zerodur density standard spheres is built, and the weight
exchanger, which is composed of a weight pan with the shape of a conoid and the standard weights with a slot, is constructed. In addition, the temperature and density gradient of transfer liquid are precisely corrected according to the measuring position of the liquid container. As a result, the volume of 1 kg standard weight in a class E1 obtains 124,90388 cm³ at 20°C with a precision of 8.4·10-5 cm³ (0,67 ppm) by hydrostatic weighing, and the measurement uncertainty shows 3.0·10-4 cm³ (2,4 ppm) in a confidence
level of 95% with coverage factor k = 2.