Signal detection via the pole wheelSignal detection via the pole wheelWith this method, the impulse transmitter detects the impulses via a pole wheel, which is attached to the measurement screw. Based on specifications and need, pole wheels with differing numbers of poles can be used. This enables a significantly higher signal transfer resolution. Signal detection via the pole wheel is used when a high signal resolution is needed, e.g., with test and calibration benches or with the use of a flowmeter in the lower flow range.

KRAL Flowmeters OMH Series.

For high pressures with highest accuracy.

With high pressure to an accurate measuring result.
The KRAL flow meters OMH series were especially designed to handle high pressures of up to 420 bar that can occur in the field of mechanical engineering, at test benches and in hydraulic applications.

Large flow ranges usually require large pipe cross sections and are therefore bulky flow metering devices. Due to the compact measuring element, the OMH series fits into a small housing and offers the significant advantage of being compact and lightweight in this pressure class, even for high flow rates.

The pressure resistance is provided by a very rigid housing, maintaining the compact dimensions, and at the same time the proven precision of the KRAL flow meters, even at extreme pressure levels.

Your benefits.

  • Multiple port connections available.
  • High pressures up to 420 bar.
  • High precision flow meters.
  • Very rigid spheroidal graphite iron housing.
  • Compact size, light weight.
  • Low friction and minimal loss of pressure.
  • Stabilization zones unnecessary.

Technical data.

  • Media: Chemically neutral, lubricating, clean, non-abrasive.
  • Flow sensor: Liquid flow direction detection. Extended sensor range optional.
  • Temperature measurement: Additional sensor optional.
  • Signal: PNP, Namur and Push-pull.
  • Process fittings: DIN, thread.


  • Housing: Spheroidal graphite iron.
  • Screws: Nitrided steel.
  • Bearings: Steel ball bearings.
  • Sealing: FKM, other seal materials upon request.
  • Technical data.
    Technical dataOMH-013OMH-020OMH-032OMH-052OMH-068OMH-0100
    Nominal diameter DN [inch]1/23/411 1/224
    Total length with threaded flange G[mm]150185255320385500
    Weight with threaded flange G[Kg]712295581150
    Flow rate I/hQmax9002,7009,00031,50063,000180,000
    Flow rate I/minQmax15451505251,0503,000
    Max. pressure [bar]420420420420420250
    Temperature[°C]-20 to +200-20 to +200-20 to +200-20 to +200-20 to +200-20 to +200
    Viscosity [mm²/s]1 to 1x1061 to 1x1061 to 1x1061 to 1x1061 to 1x1061 to 1x106
    Precisionof measurement value±0.1 %±0.1 %±0.1 %±0.1 %±0.1 %±0.1 %
    Repeatability ±0.01 %±0.01 %±0.01 %±0.01 %±0.01 %±0.01 %
    K-factorK2 [P/I]2,4321,28046814279.633.6
     K3 [P/I]7,2962,5601,01430216757.6
     K4 [P/I]7,2962,5601,01430216787.6
    Frequencyf2 at Qnom [Hz]4056407808289291,120
     f3 at Qnom [Hz]1,2161,2801,6901,7601,9491,920
     f4 at Qnom [Hz]1,2161,2801,6901,7621,9482,920
  • Sensor.
    SensorBEG 06 / BEG 06A*BEG 44ABEG 45 with BEV 13BEG 53A / BEG 54A*
    Application Ex-rangeHigh pressures, broad temperature rangeHigh pressures, broad temperature rangeFlow direction detection
    K-factor K1K2K3K4
    Signal NamurPNPPNPPush-Pull
    Temperature[°C]-40 to +150-40 to +150-40 to +250-40 to +125
    Max. pressure [bar]350420420650
    *dependent on nominal value 
  • Operating instructions.