High-level detection for electrostatic precipitators

Suspended particles that are filtered out of the process exhaust air are collected in hoppers. If the level in these hoppers rises too high that the fine dust touches the electrostatic precipitators, these precipitators will short-circuit causing a process upset condition. To prevent this, the high level must be reliably measured. Radiometric level switches offer best in class reliability for this application. 
Geiger-Müller (GM) technology radiation level switches were historically used for these applications. However, in plants that have been in operation for a long time, the activity of the radioactive source has decreased significantly due to natural source decay. The sensitivity of the GM detectors is then no longer sufficient to reliably continue limit switch measurements. Replacements or retrofit solutions become necessary.

High-level measurement system LB 471

If it is legally and technically possible to use an existing radiation source over the recommended operating time, the existing GM level switches can be replaced by the more sensitive LB 471 scintillator measurement system from Berthold. Commonly, an additional 10 to 15 years of operation are possible with the existing measurement source left in place. Berthold‘s LB 471 scintillator measurement system provides reliable level switch detection without the effort and expense of disposal and replacement of the existing radiation source. The LB 471 level switch measurement system is either available in a wall-mounted housing or in a 19“ rack (for up to 19 limit switches).


  • “Retrofit” installation on existing measurements, where the source has become too weak
  • High availability and thus high operational reliability
  • One-time calibration, no recalibration required

Customer benefits

  • Best in class sensitivity
  • Proven industrial measurement technology
  • Real-time measurement during operation
  • Wear-free and maintenance-free
  • Simple installation on the outside of the vessel




High level measurement in ash hoppers Application flyer

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Berthold's measurement solution