Signal detection via the measuring screw Signal detection via the measuring screw In the case of signal acquisition via the measuring screw, the screw edge is detected by an impulse transmitter. Two edges per screw revolution are detected, which causes two impulses per screw revolution. Because a screw revolution conveys the exact volume of the measurement chamber, two impulses per measurement chamber volume are generated. This type of signal detection is an affordable solution for all conventional consumption and flow measurement applications.

KRAL Flowmeters OMP Series.

Robust solution for flow measurement of diesel and heavy fuel oil.

The OMP series flowmeters are designed specifically for fuel consumption measurement for marine applications as well as others, and can be used in booster modules and burners.

A perfect combination of precision and robustness: Due to the precise measurement chamber volume, a broad range of measurements with a precision rate of 0.1 % can be achieved. Pipe bends and T-sections have no influence on the measurement accuracy or performance of the KRAL flow meter.

The extreme robustness is achieved by the spheroidal graphite iron housing, which provides optimal protection for the precisely manufactured screws. The screws of KRAL flowmeters quickly follow the changes of the fuel flow rate, the fuel pulses and may even change its flow direction briefly.

The measurement devices run with low friction, gentle and with minimal pressure loss. Long lifespan, resistance to pulsations in the media, and efficiency across the entire product life cycle are just a few of the benefits that KRAL flowmeter OMP offers.

Your benefits.

  • KRAL flow meter suitable for Marine diesel oil (MDO), Marine gas oil (MGO), Heavy fuel oil (HFO) and further types of oil.
  • High accuracy flow measurement of fuel flow and oil flow.
  • Very robust and long life time meter.
  • Low friction and minimal loss of pressure.
  • Stabilization zones unnecessary.
  • Easy installation.
  • Suitable for harsh industrial conditions.

Technical data.

  • Media: Chemically neutral, lubricating, clean, non-abrasive, diesel and heavy fuel oil.
  • Flow direction detection: Second sensor range optional.
  • Temperature measurement: Additional sensor optional.
  • Sensor: PNP or Namur signal.
  • Process fittings: DIN, ANSI, thread. Further connections upon request.


  • Housing: Spheroidal graphite iron.
  • Screws: Nitrided steel.
  • Bearings: Hybrid ball bearings.
  • Sealing: FKM, other seal materials upon request.
  • Technical data.
    Technical data OMP-13 OMP-20 OMP-32 OMP-52
    Nominal diameter DN [mm] 15 20 25/32 40
      DN [inch] 1/2 3/4 1 1 1/2
    Total length with DIN flange [mm] 115 125 180/190 240
    Weight with DIN flange [kg] 4 5 11/13 19
    Flow rate I/h Qmax 900 2,700 9,000 31,500
      Qnom 600 1,800 6,000 21,000
      Qmin 6 18 60 210
    Flow rate I/min Qmax 15 45 150 525
      Qnom 10 30 100 350
      Qmin 0.1 0.3 1.0 3.5
    Max. pressure [bar] 40 40 40 40
    Temperature [°C] -20 to +200 -20 to +200 -20 to +200 -20 to +200
    Viscosity [mm²/s] 1 to 1x106 1 to 1x106 1 to 1x106 1 to 1x106
    Precision of measurement value ±0.1 % ±0.1 % ±0.1 % ±0.1 %
    Repeatability   ±0.01 % ±0.01 % ±0.01 % ±0.01 %
    K-factor K [P/I] 1,214.0 321.0 78.0 17.73
    Frequency f at Qnom [Hz] 202 161 130 104
  • Sensor.
    Sensor BEG 45C with BEV 13 BEG 47G BEG 56A
    Application   High pressures,
    wide temperature range
    Ex-range Standard
    K-factor   K1 K1 K1
    Signal   PNP Namur PNP
    Temperature [°C] -40 to +250 -25 to +100 -40 to +125
    Max. pressure [bar] 420 40 40
  • Operating instructions.