ExactSonic II - portable ultrasonic flow meter for liquids

This principle of measurement is also referred to as the transit time difference method. For measuring the flow rate of liquids using this technique, ultrasonic pulses are sent and received simultaneously through the medium in the direction of flow and against it. The sensors work alternately as transmitter and receiver. The transit time of the acoustic signals filtered through the medium in the direction of flow is shorter than that against it. The difference in transit time Δt is measured and can be used to calculate the average flow velocity of liquids filtering through the acoustic path. After measuring the flow velocity and with the pipe cross-sectional area, volumetric flow can be calculated.


These ultrasonic flowmeters have many benefits, for example, the measuring instruments produce accurate results in just a matter of minutes, they are easy to install and operate, there is no process interruption and there are no pipe restrictions. As a result, there is no pressure loss and therefore, time and cost savings as the ultrasonic flow meter is easy to install on the pipe.

Advantages of non-invasive measuring with the ultrasonic flowmeters:

  • installation without process interruption or shut-down
  • easy and cost-effective assembly
  • light-weight ergonomic design
  • ideal for use in maintenance areas and commissioning
  • testing fixed measuring equipment

Device-related advantages of the ultrasonic flow measurement equipment compared to other products:

  • no zero point alignment of the flow meter necessary
  • coverage of the most frequent industrial applications for flow measurement of liquids with just two transducer sets
  • high-capacity data logger with numerous parameters for pipe materials and mediums
  • stable and reliable results even under difficult conditions
  • excellent reproducibility of results

Measurement-related advantages of the ultrasonic flow meter:

  • non-contact measurement
  • independent of pressure, temperature, conductivity and viscosity
  • unlimited plant availability, as no process interruption
  • no pressure losses when measuring flow rate, no risk of leakage, no cleaning necessary
  • no mismeasurements as a result of blocked impulse pipes
  • logging of lowest flow velocities (min. 0.2 m/s) resulting in high measuring dynamics

Cost advantages of the ultrasonic flowmeters:

  • easy retrofitting
  • low-cost installation and upkeep
  • no maintenance effort or cleaning process necessary

resulting in an excellent cost-benefit ratio.


Flow rate measurement in liquid-filled pipes, HVAC systems, pump and technical system verification, boiler testing, leak detection, filter sizing, fire and hydraulic systems.

Non-contact measurement from the outside means that the ultrasonic flow measuring instrument is indispensable in many branches of industry, such as, water management, building services, energy sector, chemical and pharmaceutical, food technology and petrochemical.

Ultrasonic flow measuring instruments can be used in the following industries:

Aggressive, toxic, high-viscosity and non-conductive fluids

Flow measurement of various intermediate or end products, e.g. tar, bitumen

Offshore Industry
Measuring liquid hydrocarbon

Power plants
Operational measuring of coolants and boiler feed water, condensate

Pharmaceutical, Semiconductor Industry
Ultrapure liquids / fluids

Beverage industry
Hygienic measuring in bottling plants or tank installations

Water / sewage
Measuring in large pipes and underground pipes and ducts

Plant engineering and construction
Any flow rate measurement, e.g. leakage detection in hydraulic plants, pump verification

Testing hydraulic, supply and cooling systems

These are just some examples of typical mediums in various branches of industry.

Other mediums suited for this principle of measurement:
de-mineralized water, drinking water, river water, water-glycol mixtures, hydraulic oil, diesel, fuel oil, petroleum products, etc.

Technical Data of the ultrasonic flow measuring instrument:

  • flow velocity range 0.2 … 20 m/s
  • bi-directional
  • measurement uncertainty: pipe OD > 75 mm: ± 2 % of measured value
  • menu-oriented operation
  • backlit graphic display, 64 x 240 pixels
  • programming via 16 key control panel
  • battery or mains operation
  • battery life up to 20 hours
  • power 110 … 240 VAC +/-10 %
  • 10 user selectable languages: German, English, French, Italian, Dutch, Swedish, Norwegian, Portuguese, Russian, Spanish
  • incl. two transducer sets 'A' & 'B': pair 'A' for pipe OD 13 … 115 mm
    pair 'B' for pipe OD 50 … 2000 mm
  • transducer working temperature range: -20 … +135 °C
  • outputs 0/4-20 mA, RS232/USB, opto-isolated, pulse output 5 V, max. 1 pulse/s
  • data logger: 98000 data points, 20 named record blocks, display in text or graph format, download via RS232/USB to Windows PC
  • delivered with robust IP67 carrying case