Measuring the concentration with the ultrasonic analyser

The heart of the system is the cell, in which ultrasonic waves are being generated and received. This cell can be an externally mounted cell, in a bypass, but may as well be a measuring section, where the liquid is analyzed while flowing through the pipe. Several probe designs facilitate the measurement of concentration inside tanks and pipelines.

The ultrasonic transducer generates short, highly damped ultrasonic pulses in the frequency range of 1 to 7,5 MHz. These sound waves propagate through the liquid with a yet unknown sound speed and meet a second transducer, which converts the received sound waves into electrical pulses.

The first technology used is the calculation of the speed of sound. This is done by registration of the arrival times of the received signals, which is very precisely measured and processed. Sound velocity is a very characteristic property of a fluid, that is affected by the density and the modulus of compressibility.

The second technology that Rhosonics uses is the determination of the loss of energy of the pulses (attenuation). Energy loss is due by particles. We can determine the amount of solids in slurries, sludge or in the production of molymers.

The third technology that Rhosonics offer is ultrasonic spectrometry to determine certain properties of materials. This technology is used in laboratories and universities.

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

Rhosonics designed and uses a special tool, based on DSP technology, “UltraSmart” that enables better analysis of the pulses resulting in much higher accuracy. Gas bubbles, external influences, weakening of the signal and any other influence are recognized and discard from the measurement.