National ESZ force standard 1 MN

The state standard ESZ 1 MN is designed for calibration of standard force gauges with nominal forces from 200 kN to 1 MN under tensile and compressive loading.

 

The standard was custom-made for the Office for Standardization and Measurement (ÚNM) by WPM in Leipzig. It was installed in the laboratory of force in the building of the then Regional Department of the Institute of National Statistics in Prague 1, Celnice 5. It was put into operation in 1958.  It served as a force standard in the ÚNM until the establishment of the CSMI. After the establishment of the CSMI in 1968, it was taken over with the entire laboratory as a force standard for calibration of force standards in the range of nominal forces from 200 kN to 1 MN. Here the standard was used until 1979. In 1979 the standard was dismantled and stored in the company TONAVA in Úpice. The reason for the dismantling was the destruction of the laboratory building due to the reconstruction of the area around the Square of the Republic.  After the construction of a laboratory on the premises of TONAVA in Batňovice, the standard was installed in this laboratory. The standard was put back into operation in 1985. The standard was operated in this laboratory until mid-2011. In 2002, it was declared the state standard of strength.  After the construction of a new force laboratory in Prague 10, Radiova 3, the standard was dismantled in the existing laboratory in 2011. After modifications, the parts of the standard were transported with the newly manufactured parts to the new force laboratory. The standard was installed in this laboratory in 2012.  The first major reconstruction of the standard took place between 1979 and 1985. The second major reconstruction took place between 2009 and 2012. The theoretical and experimental work between 1979 and 2001 was carried out by a team led by Ing. M. Chlumský managed to prepare the etalon scientifically and technically for the announcement of the state etalon, which was successfully carried out in 2002.

 

The calibration force of the etalon is generated by the action of the earth's gravitational field on the load bodies of the etalon and amplified by a lever gear with a ratio of 1:20. The standard has two load cell systems. The small load cell system contains 10 load cells to generate a force of 250 N each, and the large load cell system contains 20 load cells to generate a force of 2500 N each.

 

The force generated by the standard is given by the equation