Bühler Technologies GmbH

Filter Monitoring

Filter Monitoring

In stationary hydraulics and lubrication systems, return line filters or line filters are conventionally monitored using contamination indicators.

The contamination indicators from Bühler Technologies enable these filters to be utilised particularly economically. They continuously monitor the filter capacity and are an important component of condition monitoring. They transform industrial filters into intelligent wear sensors that help to monitor wear in the overall hydraulic system and enable timely intervention.

Bühler Technologies has specialised in filter contamination sensors for detecting differential pressure. The differential pressure in line filters arises between the filter inlet and outlet side and is generated as a result of particle separation on the filter elements. The clogging indicator converts the pressure loss into an electrical signal.

The BCI series from Bühler Technologies, short for "Bühler Clogging Indicator", monitors the differential pressure in line filters and generates electrical output signals proportional to the decreasing filter capacity. Many of the BCI variants are available with IO-Link. Thanks to IO-Link technology, these variants can be easily integrated into existing systems and support condition-based maintenance of the filters for smooth operation without unplanned downtime.

The filter contamination sensors with IO-Link technology are innovative, networked and predictive - they pave the way to greater efficiency in the direction of Industry 4.0.


  • Contamination indicator BCI 24-Dx
    Contamination indicator BCI 24-Dx-4 (Aluminium)
    • Continuous differential pressure measurement (differential pressure range: 3 bar, 6 bar)
    • 2 freely adjustable switching outputs for the degree of soiling (default setting at 75 % and 100 % degree of soiling)
    • 4-20 mA output for differential pressure (variant 1D1A)
    • IO-Link for easy integration into existing systems
    • IO-Link technology standard in all versions
    • Continuous filter monitoring for optimised service planning
    • Connection flange compatible with third-party products G1/2 Hydac, G1/2 Stauff, M20x1.5 Filtration Group, M20x1.5 Hengst, G1/2 MP-Filtri or G1/2 Eaton
    • Operating pressure up to 400 bar
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  • [Translate to English:]
    Contamination indicator BCI 24-Dx (stainless steel)
    • Continuous differential pressure measurement (differential pressure range: 3 bar, 6 bar)
    • 2 switching outputs for the degree of soiling (default setting at 75 % and 100 % degree of soiling)
    • 4-20 mA output for differential pressure (variant 2S1A)
    • With IO-Link variant 1x programmable switching output (variant 1D1S)
    • Signal suppression of the outputs during the cold start phase (variant 2S1A)
    • Connection flange compatible with third-party products G1/2 Hydac, G1/2 Stauff, M20x1.5 Filtration Group, M20x1.5 Hengst, G1/2 MP-Filtri or G1/2 Eaton
    • Operating pressure up to 400 bar
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  • Product Archive
    • [Translate to English:] Prozessor gesteuerter Differenz-Druck-Sensor zur Überwachung von Filter-Zustand
      Differential pressure sensor VSA 24-D
      • two switching outputs
      • signal suppression during the cold start phase and for short-term pressure peaks
      • visual / electrical display of status and error messages
      • self-monitoring
      • LED illuminated halo visible from every angle
      • display of status and error messages
      • M12 connector
      • reset function
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    • [Translate to English:] Prozessor-gesteuerter Stau-Druck-Schalter und Temperatur-Sensor
      Back pressure sensor VSA 24-S
      • two switching outputs
      • signal suppression during the cold start phase and for short-term pressure peaks
      • visual / electrical display of status and error messages
      • self-monitoring
      • reset function
      • LED illuminated halo visible from every angle
      Show details