Realisation of New Primary Standard of Gas Flow

This paper describes the process of developing a new national standard for gas flow in the Czech Republic. An important part is the result of a literature study on primary standards found in different laboratories of national metrology institutes around the world. The principles of operation, schematics and photographs of different types of primary standards and their usual range of flow rates and pressures are presented. In the following section the specification and detailed description of the selected type of primary standard is given. This primary standard is already under construction in the Czech Republic following the conclusions of literature study. In principle, it is a Bell Piston Prover with a planned flow range of 2 L/h to 2 m³/h.