Calibration Of Hydrometers By Solid Density Standard

Density measurement has extensive links with various fields such as petrochemicals,metrology,national defense research,and people's life.Hydrometers?glass densitometers?are one of the commonly used density measurement methods.Currently,there are glass float calibration devices.It does not meet the calibration needs required by existing markets.At the same time,a new glass floating meter calibration system should be established,which can trace the working density meter group to the solid density working standard,improve the accuracy of the glass floating meter measurement,and avoid the use of harmful liquids..In accordance with the new density measurement system,two mass transfer processes are used.Firstly,the solid density standard is transferred to the solid density standard single crystal silicon ring through the steady state suspension method,and then the solid density standard amount is measured by the static weighing method.Passed to the working fluid density,the calibration of hydrometers is achieved by the liquid density.The main research work is as follows:1.Investigate the current status of density measurement,analyze the parameters and variables that need to be measured in the experiment,and establish a mathematical model by simplifying the operation and logic derivation,and convert the relative density difference of the single crystal silicon material into pressure and temperature.Calculate and clarify the parameters and measurement steps required for hydrometers;2.Selecting the device according to the accuracy,respectively establishing a solid density mass transfer device and a hydrometer gauge calibration device,analyzing the performance of the respective subsystems,ensuring the stability of the two experimental temperature parameters,and performing the respective working fluids.3.Complete the density measurement of the monocrystalline silicon density standard to ensure the accuracy of the measurement uncertainty reaches 10^-7.At the same time,in order to verify the measurement accuracy of the calibration system,four glass densitometers are selected for the German Metrology Institute and China.The glass floating meter verification device of the Metrology Institute conducts comparative analysis to ensure that the relative expansion uncertainty of the glass float meter is below 0.3 graduation value?k=2?.