Simultaneous calibration of the mass and the volume of weights in the range from 1 kg to 20 kg

Two fully-automatic mass comparators housed in each airtight chamber have been installed for simultaneous calibration of the mass and volume of weights in the range from 1 kg to 20 kg. One is a 10 kg mass comparator having a readability of 0.01 mg and the other is a 20 kg mass comparator having a readability of 0.1 mg. These mass comparators are equipped with a four position weight exchanger and carry out an automatic mass comparison. The chambers can keep the air density constant at a fixed value within the range from 0.6 kg/m³ to 1.2 kg/m³ by changing its internal pressure from 60 kPa to 102 kPa and thereby the mass and the volume of a test weight can be simultaneously evaluated. In this paper the features and results of performance tests of the mass comparators are described.