Reasons for the instability of metrological characteristics of analytical balances

Conclusions

• 1. The main reason for the instability of the metrological characteristics of VM-20 and ADV-200 balances consists in the destruction of the knife-edge blades during operation of the balances. It is necessary radically to improve the quality of this important component of balances in order to raise the quality of the balances as a whole.

• 2. The beams of the ADV-200 and VM-20 balances are sufficiently rigid. The sagging under load of the beam of these balances is so small that it has virtually no effect on the metrological characteristics of the balances.

• 3. The dead zone of the ADV-200 balances, if it exists at all, is smaller than 0.7″, i.e. it is considerably less than the reading accuracy of these balances.

• 4. The main reason for temperature affecting the scale factor of the balances lies in the use of nonuniform materials for the balance beam components. In order to reduce the effect of temperature on the sensitivity of the balances it is necessary to choose for the beam and the components attached to it materials which have linear expansion coefficients as close to each other as possible [7].