Ultrasonic concentration analyzers

Here at Rhosonics, we continuously work on improving our analyzers and sensors. Since the introduction of the first analyser in 1992, Model 8000, the available amount of applications, models, and variants has been increased dramatically. We believe that we can offer solutions for almost any application. We can help you by adapting our solutions to improve your production processes.

Both the models 8000 (1992) and 8100 (1995) are still used worldwide. These analyzers are sometimes upgraded in our facility to enable them to work in new production processes used by the same client. Sometimes, we recommend clients to use a new analyser, which has more features and, because of newer sensors, is generally at least ten times more accurate.

Thanks to a highly innovative design with respect to electronics and sensor technology, continuous and extremely accurate in-line monitoring of fluid mixtures is now, with virtually no need for regular maintenance due to the lack of moving or degrading parts.


The core of the system is the cell, in which ultrasonic waves are generated and received. This cell can be mounted externally, in a bypass, but can also be deployed as a measuring section, where the liquid is analyzed while it flows through the pipe. Several probe designs aid the measurement of density inside tanks and pipelines.

The ultrasonic transducer generates short, highly dampened ultrasonic pulses in the frequency range between 1 and 7,5 MHz. These sound waves propagate through the liquid with a yet unknown speed until they reach a second transducer, which converts the received sound waves into electrical pulses.

Our first technology calculates the speed at which the sound travelled through the liquid. This is done by registrating precisely when the signal was received. The speed at which sound travels through a liquid is affected by the fluid’s density and the modulus of the substance’s compressibility.

Our second technology determines the rate of loss of energy of the pulses (attenuation). Energy loss is the result of action by particles. We can determine the amount of solids in slurries, sludge, or in the production of polymers.

Our third technology consists of ultrasonic spectrometry, which is used to determine certain properties of materials. This technology is used in laboratories and universities.

Based on temperature, path length, and application, the concentration or density of a liquid can be determined very accurately by means of a polynomial equation. It compensates for non-linear behavior of the liquid. The constants of the polynomial equation are entered though a touchscreen. These constants are known for many liquids and have been determined in the Rhosonics laboratory.

Rhosonics has designed a special tool, based on DSP technology, called “UltraSmart”, which enables better analysis of the pulses, securing much more accurate readings. External influences, weakening of the signal, and any other influences are identified and discarded from the measurement.

Depending on the application, you pick from a number of different sensors. An extractive measurement is almost always possible, especially with low sample volumes, such as in pilot plants. For the food industry we offer sanitary sensors. Finally, we also offer a broad range of connectors, like tri-clamps, ISO, flanges, and clamp-on sensors.


Naturally, not all liquids can be measured using ultrasonic measuring technology. In many cases, the 8500 is the ideal choice for your in-line process analysis.

Acids form one category of liquids that can be measured with a high degree of accuracy. Most acids possess such an extremely high change in sound speed compared to density, that the accuracy of the measurement is comparable to that performed in laboratory analysis. Examples of such acids include sulphuric acid, nitric acid, hydrochloric acid, and phosphoric acid.

Bases have sometimes an even more astonishing change in the speed with which sound travels through the liquid in question. Looking at the graph of potassium hydroxide, you will find that a sound velocity change of about 25 m/s is more than enough to ensure a highly accurate analysis.

Alcohols, such as glycol, ethanol, and methanol, are also easy to measure accurately.

Food products, like beer, wine, syrups, edible oils and fats, fruit juices, as well as dairy products (milk, yoghurt), can easily be monitored. In liquids with suspended solids, the speed at which sound travels through the liquid in question depends on the amount of solids in the mix. In some cases, the attenuation is affected by solids as well. Examples of applications are milk and margarine. Non-aqueous solutions as well as liquids with dissolved or suspended solids, are compatible with the Rhosonics analyzer.

Non-destructive testing

Rhosonics has developed ToFD inspection solutions, which are used worldwide for demanding applications. Inspection companies benefit from Rhosonics’ expertise in this field. Rhosonics has been supplying transducers, wedges and other components for automated ToFD since its founding in 1991.

Some major products:

  • Piezo composite screw-in type of transducers.
  • High-temperature wedges for screw-in transducers
  • Wedges for screw-in transducers
  • Amplifiers
  • Phased array transducers
  • Ultrasonic NDT

Access to new TOFD capabilities

Miniature sensors with integrated wedge, allow good coupling on the profile of the parts to be tested and offer great testing flexibility.

For penetration tubes inspection, 1.5 mm thick probes can be inserted in the space available for inspection.

This detects cracks, determines the size of cracks, and also allows the monitoring of cracks, regardless of type and/or orientation, through the use of diffracted sound coming from the flaw tips.

Advantages of the technique

The piezo composite technology, as used by Rhosonics for ToFD testing of machines, boilers, vessels and pipes, offers inspection engineers the following advantages:

  • High sensitivity and s/n ratio (+10 to + 50dB) compared to conventional TOFD transducers, while maintaining a short pulse length
  • Centre frequency from 1 to 15 MHz
  • Access to difficult area thanks to miniaturisation
  • Tight specification level
  • Extremely long life time, even under the normally rugged field conditions

Main characteristics:

  • Active part in piezocomposite material
  • Centre frequency (-6dB) : from 1 MHz to 15 MHz
  • Relative bandwidth (-6dB) : 60 to 90 %
  • Acoustic impedance matched to wedge material
  • Watertight stainless steel housing
  • Wedges system capabilities
  • Full range, from 10 to 90 degree longitudinal in steel
  • Shear wave wedges
  • High temperature wedges, up to 460 degrees C
  • Low noise pre-amplifiers for field operations
  • Special wedges available for Phases Array systems