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In times of rising energy costs real time monitoring of fuel consumption is crucial to determine optimal engine efficiency. Thus, it is necessary to measure the flow rate differential at the fuel circulation lines.

The particular measurement points are close to the engine with temperature of up to 160 °C and heavily vibrating pipes. Highly reliable, repeatable and accurate measurements are crucial under such rough conditions.

Conventional wetted flow meters are facing considerable wear by the hot medium and mechanical stress, leading to significant maintenance efforts. Furthermore, it is crucial that the meters at the supply and return line are matched and do not drift over time as the aim is to monitor the flow rate differential (consumed fuel). Especially at low cruising speeds, the fuel circulating is much higher than the consumption – this is where high measurement precision and repeatability is required.

FLEXIM’s ultrasonic clamp-on flow meters are the ideal choice for such applications:

Being mounted outside the pipe, installation efforts are minimal. No pipe modifications or process shut-downs are necessary and the transducers can be installed at even the most confined spaces. Being equipped with permanent coupling, vibration resistant stainless steel mountings and withstanding temperatures up to 200 °C and more, FLUXUS ensures an unrivalled durability.

Furthermore, by making use of its dual channels, one measurement channel is installed at the supply line and the other at the return line, the flow transmitter easily calculates the flow rate differential. As the systems ultrasonic transducers are carefully matched and factory calibrated, even very low flow rate differentials are captured with highest precision.

FLEXIM’s clamp-on ultrasonic measurement systems not only allow volume flow measurement but also mass flow and density measurements. By making use of its non-invasive temperature probes, the FLUXUS HPI meter outputs mass flow rates and detects even the slightest density changes.


Clamp-on ultrasonic flow meter are not only ideal for fuel oil consumption monitoring but also for fuel oil measurements between bunkering and daily service tanks as well as at cooling and lubrication oil lines

FLUXUS has been proven in numerous fuel consumption metering applications at US Navy vessels as well as many commercial vessels. Besides the engine supply and return lines, FLUXUS also measures at dedicated points between Bunker, Daily Tanks and Mix Tanks.

What applies for engine fuel lines is also applicable for cooling circuits as well as lubrication oil lines. The FLUXUS flow meter is not affected by changes in viscosity – even entrained particles do not affect the measurement, but can be diagnosed when exceeding a defined threshold.


  • Highly precise, repeatable and drift-free metering system for engine fuel consumption monitoring
  • Volume compensation through direct, non-invasive temperature measurement – displays mass flow rate and density
  • Virtually unlimited measuring range, highly accurate at high as well as very low flow rates
  • Independent of demanding conditions (high temperatures, vibrating pipes, etc.)
  • Highly cost efficient:
    - Easy retrofitting with no pipe modification / cutting requirements
    - Long-term stable, no direct media contact, no maintenance requirements
    - One flow meter for monitoring of two fuel lines