Performance advantages: density meter and a float-type hydrometer density meter, hydrostatic density meter, vibrating density meter and radioisotope details hydrometer density meter calibration principle: objects gravity pulling objects to the ground, but if the object placed in the liquid, called buoyancy forces will produce the opposite direction of the force. The size of the buoyancy of the liquid equal to the gravity of the object substituted, or is of the gravity of the fluid in the longitudinal grant instrument calibration, instrument calibration temperature, mechanical instrument calibration, electromagnetic detection equipment, radio measurement calibration, calibration measurement time and frequency, Physical chemistry and other ten categories Calibration of 127 professional instrument calibration work to carry out the project