Apparatus for Reproducing Absolute Pressure by a Thermodynamic Method

Apparatus for reproducing the unit of absolute pressure by a thermodynamic method in the 133 – 1·10⁵ Pa range is described. Argon, nitrogen and oxygen are used as the working materials. The pressure is reproduced at triple points and also on the p–T-equilibrium curves of two phases. The processes of attaining a specified point on the p–T-curve and of stabilizing the process at this point are automated using the AKSAMIT measurement-control device. The relative error in reproducing the pressure is 0.01% of the reproduced value.