A New Design of Deadweight Force Standard Machine with Substitute Load Control and Self-checking Systems

摘要

A new dead weight force standard machine covering the range from 10 kN to 1 MN has been designed and constructed at the National Institute for Standards (NIS)-Egypt, by GTM GmbH. This machine incorporates an electromechanical system that allows the generation of any load from 10 kN to 500 kN in steps of 5 kN with only 10 masses by selecting a suitable combination of these, while keeping the load on the transducer under calibration constant. Furthermore, it allows the generation of additional loads of up to 500 kN, so that 1 MN is reached by full deadweight action and full substitute load at the same time without significant loss of accuracy. The forces generated by the various masses can be checked against a reference mass without any dismantling operation. The machine also serves as a precision pressure balance of a 5 MN hydraulic force standard machine. The amplification system formed is of 10:1 ratio. The paper presents the special design features of the machine and the design considerations with a brief account of the verification of the machine. A second paper will follow to present the evaluation of the metrological characteristics of the developed machine.