Density meter
Measures the density or specific gravity of a liquid in about a minute, using a vibrating glass U-tube. It replaces the pycnometer for most routine work.
- Pharmaceutical
- Food & beverage
- Spirits & brewing
- Chemicals
- Petrochemicals
Test your Density meter knowledge
Multiple-choice questions
Pick an answer to see whether you are right and why.
Q1. The density of pure water at 20 °C is about:
basicQ2. A digital density meter measures:
basicQ3. An air bubble in the U-tube will make the density reading:
intermediateQ4. Which two substances are normally used for the daily check of a density meter?
intermediateQ5. Specific gravity (relative density) is:
intermediateQ6. Why do modern density meters include a viscosity correction?
advanced
Viva questions
Think of your answer first, then open it to compare.
1. What do you do if the water check fails in the morning?
Do not use the instrument. Clean and dry the tube, check for bubbles and use fresh degassed water, then repeat. If it still fails, perform the air and water adjustment, verify with a certified standard, and if it still fails, call service and inform the supervisor.
2. Compare the pycnometer method with the oscillating U-tube method.
The pycnometer is a glass bottle of known volume weighed empty and full; it is simple and needs no special instrument but is slow and operator-dependent. The U-tube meter is fast, uses a small volume and is very precise, but needs regular air and water checks and is sensitive to bubbles.
3. Why must sugar syrups be rinsed out of the U-tube straight away?
If the syrup dries in the tube it leaves a sugar deposit. The deposit adds mass to the tube, which changes its vibration and makes later readings wrong until it is removed.
Keep every Density meter in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.