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Hydrometer is a glass body that
dipped into the liquid. After a short equilibration time it will swim at
a certain level (when the mass of the hydrometer is equal to the
buoyancy force effect). The level of equilibration reads the
density
on the calibrated scale. Hydrometer need to calibrate at accredited
laboratory or National Metrology Institute.
Hydrometer can measure the
densities
of a wide range of the liquid. Hydrometer usually used in petroleum
industry, alcoholic drink, sugar solution and food industry. Hydrometer
is a very important to industries because hydrometer can check the
quality of the industry product.
Calibration of a hydrometer by the sinker
method :
Calibration of a hydrometer by the sinker
method is by observation of the reading of the floating hydrometer and a
determination of the density of the liquid. A sinker of known mass and
volume is hung from the balance.
Calibration of a hydrometer by the
hydrostatic weighing method. (Cuckow's method):
The hydrostatic
weighing system weighed the hydrometers while they were partially
immersed in the calibration liquid. A sinker was added to the
hydrometers, which ranges were below than the density of the calibration
liquid.
Calibration of a hydrometer by the
comparison method :
Calibration of a hydrometer by the
comparison method is easier compare with other calibration of the
hydrometer method. Calibration of a hydrometer by the comparison method
is the most commonly employed for routine calibration. In calibration of
a hydrometer by the comparison method, the hydrometer is calibrated by
comparing its reading against the high
precision standard hydrometer. |