Concentration Measurement with FLUXUS CMS

FLUXUS CMS with immersion probe

FLUXUS CMS allows you to determine the concentration of a solid or liquid component of a fluid using ultrasounds. The measurement is non-invasive and can be made online, at the process pressure and temperature.

The method is applicable to all acoustically transmittive fluids, independently of their conductivity and transparency, as far as a marked dependence of the sound velocity on the concentration of the component to be measured exists.

Advantages of the ultrasonic measurement:

non-invasive measurement, ideal for ultra pure or chemically aggressive fluids
measurement takes place at process temperature and pressure
many possibilities of application
little installation work needed
no clearance volume
can be modified at any time
no leakage

More about the measuring principle:

Ultrasonic Concentration Measurement

The speed of sound in a fluid depends on the fluid's density and compressibility, and therefore on the concentration of all substances diluted or mixed in it. The ultrasonic concentration measurement makes use of this dependency.

Coffee extract: linear dependency of the sound velocity on the concentration over a large concentration range

The measurement of the transit time of an ultrasonic signal in a fluid allows the determination of the sound velocity in this fluid. If the dependence of the sound velocity on the concentration of one of the substances diluted in the fluid is known, it is consequently possible to calculate the concentration of this substance.

To determine this dependency, it is necessary to measure a characteristic concentration curve of the fluid. Ultrasonic concentration measurement is only possible if the sound velocity changes by at least 0.5 m/s for every mass percent. A temperature
calibration is also necessary.

Assuming a linear or polynomial dependency (degree 1 to 4) between concentration and sound velocity, a calibration curve is determined. The temperature dependency of the resulting concentration coefficient must be taken into account (linear or polynomial).

Sulphuric acid: strong non-linear dependency between concentration and sound velocity; the measuring effect is pronounced for concentrations > 80%

<Back