The world’s most accurate density meters
Revolutionary density meter models: Digital, precise and easy determination of the density and concentration of your sample. For beverages, pharmaceutical products, cosmetics, petroleum products, aromas, chemicals, biofuels, R&D and many more. The density meter models are suitable for numerous applications in industry and research.
Each density meter model uses the revolutionary oscillating U-tube principle from Anton Paar and embodies decades of experience. A continuing focus on developing new density meters has made Anton Paar the world leader in the field of density and concentration measurement.
A Generation M density meter unites the excellent measuring performance of the DMAs with the highest possible user-friendliness. A number of new features make the sample filling and measurement process easier than ever, resulting in unrivaled reliability and traceability of the measurement values. The density meter models are robust, have a highly accurate platinum thermometer and automatic viscosity correction. The portable density meter measures density and concentration directly on-site. Its compact and lightweight design guarantees complete flexibility.
You are one step ahead with the right density meter:
- Integrated reference oscillator
- Highly accurate temperature measurement
- Automatic viscosity correction
- Utmost user-friendliness and traceability of the measurement process
- Greatest flexibility due to Plug and Play technologies
We have the right density meter for you!
Density meter from Anton Paar – intelligent, excellent, competent.
The extract content in beer wort can be measured based on density, directly at the wort kettle.
Urea ammonium nitrate (UAN) concentration analysis using Anton Paar digital density meters and refractometers
Sugar contained in must can be measured - based on the density
- What is density?
- Determination of density using the oscillating U-tube method by Anton Paar
- Determination of concentration via density measurement
What is density?
The density ρ is defined as mass divided by volume:
ρ … density
m … mass
V … volume
The unit of density is kg/m³ or g/cm³. 1 g/cm³ = 1000 kg/m³.
Mass is independent from external conditions like buoyancy in air or gravity. It agrees with weight in vacuo.
True density of liquids and gases is measured with the oscillating U-tube method.
The density of liquids and gases is highly temperature-dependent. Therefore density measurement always requires an accurate temperature measurement or control. Typically, density decreases with increasing temperature as the individual molecules require more space due to their thermal motion.
Note: Water is quite a unique liquid. The density maximum is reached at a temperature of 3,98 °C with ρ = 0.999972 g/cm³.
Determination of density using the oscillating U-tube method by Anton Paar Oscillating U-tube Method
The oscillating U-tube method is used to measure the true density of fluids. The sample is introduced into a U-shaped tube that is electronically excited to oscillate at its characteristic frequency. The characteristic frequency changes depending on the density of the sample. Via a precise determination of the characteristic frequency and an appropriate adjustment, the density of the sample is determined. Due to the high temperature dependency of density, the measuring cell has to be accurately thermostatted.
Modern high-precision density meters additionally provide:
- Viscosity correction: to enable accurate results over a large viscosity range,
- Reference oscillator: to enable accurate results over a large temperature range following just one adjustment.
Determination of concentration via density measurement
The concentration of a mixture of two components (binary mixture) can be determined by means of density measurement.
Mixing two samples with known densities A and B gives a sample whose density lies between value A and B. The exact value depends on the mixing ratio and therefore on the concentration.
Concentration measurement is also possible for so-called quasi binary mixtures:
- Mixtures containing two major components. Some additional ingredients exist in small concentrations, but due to the small impact on the bulk density, these components can be ignored.
Example: The major components of regular soft drinks are water and sugar. All other ingredients can be ignored when measuring the sugar concentration (°Brix).
- Mixtures containing several components, but only the amount of one component varies. All other ingredients are kept precisely constant.
Example: For the production of infusions several base ingredients are precisely weighed according to a receipe. In a second step this mixture is diluted with water. The concentration can be controlled by means of density measurement.
Once upon a time…
Long before the oscillating U-tube density meter was invented, people determined the density of liquids and gases using pycnometers and hydrometers.
A pycnometer is a glass bottle with a known volume which is filled with sample and then weighed. The density of the sample can be calculated from the mass and volume. A hydrometer is a glass bulb filled with a metal weight. The deeper it immerses into a liquid the lower the density (Archimedes’ principle). The density can be read off directly from the scale.
These simple and useful methods are still used today in some sectors. However, they do not have the accuracy and ease-of-use provided with density meters.
1967: The oscillating U-tube principle revolutionizes density measurement
It all began in 1967: Anton Paar presented the first digital density meter using an oscillating U-tube. This revolutionized density measurement and began to replace hydrometers and pycnometers. Two leading Austrian scientists discovered the principle and developed the prototypes. Ulrich Santner, the former CEO of Anton Paar, organized the production: the first DMA (Density Measuring Apparatus) was born.
Today: Reliable technology in state-of-the-art instruments
The DMA density meters are renowned for their reliability. They have been continuously developed and the product portfolio expanded. This has resulted in models with a patented reference oscillator (AT 399051), built-in highly precise platinum thermometer and automatic viscosity correction.
From the revolutionary oscillating U-tube in 1967 up to today’s Generation M and the portable density meter, DMA 35: Anton Paar is the world leader and sets the standard in digital density measurement.