State of the art measurement technology

Density measurement system installed on pipeline

Density measuring principle by Berthold!

The radiometric measurement of density is based on the Gamma transmission principle. Gamma radiation is attenuated as it passes through a pipeline. This attenuation is measured by a detector. The extent to which the radiation is attenuated is dependent on the density of the medium in the pipeline. The higher the density, the less radiation reaches the detector. In this way, density, concentration and solids content can be determined reliably in a non-contacting manner – regardless of pressure, temperature, viscosity, conductivity and chemical properties. This results in high reliability and low maintenance of the radiometric measuring systems, even under severe operating and environmental conditions.

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Technological Highlights

Simply and intuitive operation

  • Measurement independent of the physical properties of the material to be measured
  • Easy installation, on the outside of the pipeline
  • No changes to the piping required
  • Subsequent installation on existing systems possible without switching them off (downtime)
  • No contact with the material being measured

Quality and safety

  • No wear and maintenance-free - high availability and thus high operational reliability
  • In-house production of various point and rod sources with different isotopes
  • [SIL2] [SIL3] [EX] TÜV Süd certified
  • Long-term stable measurement without recalibration
  • Worldwide sales and on-site service from the leading manufacturer of radiometric measurement technology

Measuring principle & function

Flexible adjustments for your density measurement task

Using different detectors and sources enables us to offer customized solutions that perfectly meet your requirements. Detectors and sources can be combined in various ways and may also be inserted in dip pipes. Regardless of the measuring configuration and component aging, all systems can compensate for fluctuating temperatures, which guarantees the highest level of accuracy. Which of these possibilities is selected depends on the measurement geometry, accuracy requirements and the economic aspects.

Density measurement

90° irradiation

Standard solution

  • Ideal for medium and large pipe diameters
  • Easy installation due to preassembled  mounting device

Density measurement

30° or 45° oblique irradiation

Used if 90° irradiation is not sufficient

  • For small pipes
  • For small measuring ranges
  • Easy installation due to preassembled mounting device

Density measurement

S- or U-shaped measuring path

Used if 30° irradiation is not sufficient

  • For very small pipes
  • For extreme fine measuring ranges
  • Easy installation due to preassembled mounting device

Components used for density measurement purposes

Point sources

Point sources are widely used in literally any measurement task, whether it is density, level or the use as limit switch. They usually comprise an inner source capsule, which securely encapsulates the radioactive material and a shield with a shutter mechanism to block the radiation in a controlled way. More information

Point detectors

Detectors with a small scintillator are called point detectors. They often employ a small cylinder as scintillator, e.g. 50 mm diameter and 50 mm in height. They are typically used for density applications but also for level switch or continuous level measurements. Depending on the measurement task, other scintillator sizes may be used. Due to the small sensitive volume of a point detector it is not greatly affected from background radiation. Additionally, point detectors can be easily equipped with a lead collimator to further suppress sensitivity to background radiation.

Highly sensitive measurement systems

Berthold detectors are particularly sensitive to gamma radiation. This offers the following advantages:

  • Increased measurement accuracy and faster response times
  • High long-term stability and measured value reproducibility
  • Significantly lower source activity
  • Longer lifetime
  • Use of smaller shields and thus lower costs
  • Minimum dose rate - less than 1 μSv/h

More about sensitivity

Unique long-term detector stability

A stable and reliable measurement over years is an important quality criterion when choosing a radiometric density measurement system. Accordingly, much effort has gone into the development and optimization of this detector property. Today we are proud to say that Berthold detectors offer the best long-term stability. A patented automatic drift compensation method compensates for temperature effects, ensuring high sensitivity and consistent measurement accuracy over the life of the system and years of operation without recalibration.

Pages of Whitepaper radiometric measurement

Whitepaper "Radiometric Measurements"

Berthold has published the whitepaper “Radiometric Measurements – Accuracy, repeatability and errors”, wherein the radiometric measurements are explained and  how your process can be performed with highest accuracy and reproducibility and the error sources can be minimized. The paper explains the nature and causes of these errors, and identifies solutions where these errors can be suppressed through the application of „best practices“ and proper design.

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Publication Made to measure in Hydrocarbon Engineering

Article "Made to measure"

You want a reliable control of your fluid catalytic cracking (FCC) process, but are uncertain about the right measurement technology because of the extreme process conditions? Read the article “Made to measure” to learn why the use of radiometric measurement systems can help to optimize level control in FCC units and how Berthold systems can help you to control your process more reliably to ensure safe operation while increasing efficiency.


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