A MASS COMPARATOR INSTALLED IN AN AIR-TIGHT CHAMBER

摘要

In order to improve the reliability of weight calibration, a fully-automatic mass comparator has been installed in an airtight chamber. In the chamber, the density of the inner air is kept constant, and mass comparison can be done with the fixed environmental conditions. Consequently, a decrease of the uncertainty of the air buoyancy correction and the standard deviation of the mass comparison will be expected. An airtight chamber was made of stainless steel, divided into upper and lower cases, and has a cylindrical shape with an inner diameter of about 700 mm and height of about 740 mm. A Sartorius CC1000S-L mass comparator having a readability of 0.001 mg and carrying out automatic mass comparison between four weights was used. This paper describes the features and results of performance evaluations of the apparatus.