Density Meter Operating and Calibration Guide
Density meters measure the density and specific gravity of liquids for quality control in chemical, petroleum, food, and beverage industries.
I. Measurement Principles
- Oscillating U-Tube: The most accurate laboratory method. Measures the change in oscillation frequency of a U-shaped tube filled with the sample. Fast, requires small sample volume.
- Hydrometer: A weighted glass float that sinks to a level corresponding to the liquid density. Simple and cost-effective for field use.
- Pycnometer: A precisely calibrated glass vessel. The density is determined by weighing the vessel empty and filled with sample. Highest accuracy but time-consuming.
II. Calibration
- Air Check: Verify the empty cell reading corresponds to the air density at the measurement temperature
- Water Calibration: Fill with freshly degassed, deionized water and verify the reading matches the known water density at the measured temperature
- Verification: Measure a certified density reference standard to verify calibration accuracy
III. Operating Procedures
- Ensure the sample is homogeneous and free of bubbles. Degas carbonated or gas-saturated samples before measurement.
- Inject the sample slowly into the measuring cell to avoid bubble formation
- Allow the sample to reach thermal equilibrium with the cell before taking the reading
- Clean the cell thoroughly between samples to prevent cross-contamination
IV. Maintenance
- Clean the measuring cell after each use with appropriate solvents
- Verify calibration daily with deionized water
- Replace drying cartridges for the oscillation mechanism as needed
- Send for professional service and calibration annually
