Continuously measure level

Continuous LevelLevel (continuous) - Measuring principle by Berthold

Gamma radiation, emitted from a shielded source is attenuated as it passes through the vessel. This attenuation is measured by a highly sensitive detector, mounted at the opposite side of the vessel. As type of radiation and measuring geometry are constant the attenuation will only be affected by a change in level.

The continuous measurement of level uses a radiation field over the whole measuring range. If the level rises within the range of the radiation field, the attenuation becomes stronger and consequently the detector measures less radiation. In this manner, the level can be reliably monitored - irrespective of pressure, temperature, viscosity, color and all chemical properties.

There are different possibilities how a radiation field is formed. Either a rod detector or a rod source is used; sometimes it is most beneficial to use both in combination.

Benefits at a Glance

  • Highly accurate and reliable
  • No wear and tear
  • No maintenance required at any time
  • Unaffected by temperature, pressure, dust, colour, conductivity or chemical properties of the measured material
  • Universally applicable on all kinds of vessels,

without modification of the plant

XIP (X-Ray Interference Protection)

In industrial plants, weld inspections on pipes are regularly examined for cracks. Gamma sources with very high activity are frequently used as test equipment. Radiometric level and density measurements can however be affected by this gamma radiation and thus simulate low readings. Influencec areas of up to several 100 m distance are not uncommon. The range of ​​influence essentially depends on the activity of the test source and whether any buildings or vessels situated between the testing point and the measuring point minimize or even shield the influence.
A falsification of the measured value by external radiation can be prevented with the function XIP from Berthold Technologies. If external radiation is detected, the measured value is frozen until no external radiation is present. As long as the measured value is frozen, the measurement then signals external radiation via a binary signal, which informs the control room about this operating state. It should be noted that all Berthold level measurements are equipped with XIP.

RID (Radiation Interference Discrimination)

If you want to continue to measure with impending external radiation, then the "RID" version is required. The measurement continues without interruption, even if external radiation is present. External radiation is detected due to its different energy. The detector then changes to a second measuring channel and continues the measurement without error. This patented process makes the system particularly reliable. RID has been field tested for many years. In the new LB 470 series, operation has been made significantly more user-friendly for RID, making system calibration much easier.

Berthold Technologies has published the whitepaper “Managing Interference Radiation in Nucleonic Level Measurements”, wherein the common sources of interference radiation is identified and how affects nucleonic measurements is explained. The paper elaborates on how Berthold with its highly sophisticated RID feature helps plant operators to maintain a reliable and repeatable measurement.
It can be downloaded here

Does your product contain natural radioactive radiation?

No problem! The Product Radiation Compensation (PRC) feature provides reliable, accurate level measurement through an independent activity measurement and integral compensation. Here, two separate detector systems are used, which simultaneously measure the level and the radiation from the product. Even under difficult process conditions, a high measurement accuracy can thus be ensured.

If you already have installed radiometric measurements and are faced with the decision to replace the meanwhile weak sources, a PRC system can initially prevent the replacement of a source. Because with the PRC measurement, the background effect, which interferes more and more in the case of a weak source, is simply subtracted.

Does the gas pressure in your vessel change?

This can falsify the measured value in the case of a radiometric measurement, unless you have a gas density compensation from Berthold Technologies. With the feature GPC (Gas Property Compensation), a second measurement determines the current gas density in the vessel and compensates for the connected level measurement. Thus, a level measurement is realized, which provides an unaltered measured value even with fluctuations in the gas density.
An overview of our continuous level gauges can be found here: Continuous Level Measurement