The major difference between mazut and oil properties, in terms of the level measurement technology, is that mazut is much thicker and tends to harden. That is why it is often stored as heated up to 900С. This results, especially in winter time, in accumulation of a large amount of vapours above mazut in the tank; these vapours heavily condense on cooler surfaces, which makes normal operation of contact (displacer, float, etc.) level transmitters impossible and operation of ultrasonic level transmitters unstable (because vapours above the product cause change of an undeterminable sound velocity).
In this case, the most reliable are noncontact level-measurement methods, and ULM radar level transmitters are an excellent fit for this.
Formerly, mazut level measurement using radar level transmitters involved difficulties caused by a weakened reflected signal due to “dirt” sticking on the unprotected horn or parabolic antenna of the level transmitter as well as difficulties caused by the level transmitter's loss of the surface-reflected signal due to the product surface irregularity because mazut remains viscous even when heated and, when cooling down, can form static, slowly-changing “sags” on the surface, which leads to even weaker reflection of the probing signal. Also, when cooled, the mazut structure and, therefore, its absorbing/reflecting properties change.
When using radar level transmitters with quite low sensitivity, e.g. pulse ones or with operating frequencies of 10GHz or less, all above peculiarities of mazut result in unstable measurement, i.e. loss of the actual product level, indication spikes inconsistent with reality, and an increased actual level measurement error.
ULM radar level transmitters provide the following set of measures to avoid impact of above factors on the mazut level-measurement process:
All above measures allow ULM level transmitters to determine the mazut level steadily and with a guaranteed accuracy.