Volume flow measurement

Depending on the composition of the exhaust gas, temperature, stack diameter, and pressure conditions, etc., different measurement methods are used to determine volumetric flow and exhaust gas velocity in industrial exhaust gases: the impact pressure method or ultrasonic technology.

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Instruments for volume flow measurement

The appropriate solution for every application

Almost every kind of situation can be handled with the devices presented here.


D-FL 100 is a system for in-situ monitoring of dust emissions on smaller plants and in process applications. The system uses the double pass light attenuation principle. The system consists of a measuring head, a reflector, a purge air supply unit and a zero point reflector.


Our service staff is available at all times for the safe and smooth operation that follows: on-site service, helpdesk, remote maintenance and diagnostics as well as training in training centers or at your location. We also offer fast, reliable, world-wide supply of spare parts.

Technical data

Measuring principle
Differential pressure
Flue gas volume flow, flue gas velocity
Typical measuring ranges for CEM

0 ... 3 000 000 m3/h

2 ... 50 m/s

Benefits at a glance

  • Measurement of flue gas velocity
  • Calculation of volume flow at standard conditions
  • Adjustable parameters
  • Automatic back-purging device (optional)
  • Versions with or without counter-support and for point measurement
  • Probes: 0.4 - 2 m/up to 4 m/up to 8 m
  • Options: Display and control unit, weather protection cover, special design in other materials, dP transducer in ex-version


D-FL 220 is a system for ultrasonic (transit time difference) measuring of flow rate and volume flow, especially for wet and aggressive smoke emissions in waste incineration applications. The system consists of two measuring heads, two purge flanges, two mounting flanges, a purge air unit and a terminal box for power supply.

Technical data

Measuring principle
Acoustic propagation delay
Gas volume flow, gas velocity, temperature
Typical measuring ranges for CEM

0 ... 3 000 000 m3/h

0 ... 40 m/s

0 ... 400 °C

Benefits at a glance

  • In-situ measuring principle
  • Measurement possible below dew point and for high dust concentrations
  • Continuous measurement of volume flow and gas velocity
  • Automatic zero point and reference point control
  • Remote access possible, digital interface
  • Operation with or without control unit
  • Very low maintenance


D-ISC 100 is a universal operating and display unit in stainless steel field housing for the new generation sensors, e.g. D-FL 100, D-FL 220, D-R 220 or D-R 320. 

Technical Data

Operating and display unit
0/4 ... 20 mA; 3 x relay
Digital input


Service interface

Benefits at a glance

  • Easy set-up and automatic detection of up to eight connected sensors
  • Uniform parameterization of various sensors
  • Large LC Display for measured value display
  • Comfortable operation and handling via keyboard
  • USB interface for local device operation
  • Modular design, expansion slots and slot for external converter available
  • Easy update via SD memory card
  • Remote support via intranet/internet
  • Power supply 24 V DC/2 A for one directly connected sensor
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To remain competitive, companies in industry must ensure – and ideally increase – the availability and productivity of machines and plants. As your partner, we offer a unique range of services and support based on our extensive technology and industry expertise.

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As your partner, we offer a unique range of services and support based on our extensive technology and industry expertise. With our offerings, you can expect a high degree of reliability and a successful digital future for your company.

Well trained for excellent handling

Receive standardized or individual expertise directly from the manufacturer – with training centers in more than 60 countries.

Safety integrated

Safety is key in the process industries. A failure in instruments relevant for safety may have serious implications for humans, the process and the environment. Therefore, a wide range of our process instruments come with on-board safety features for maximum risk reduction.


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We are represented worldwide with production facilities and system integration centers. Each center, whether in Houston, Singapore, or Karlsruhe, has its own sales, engineering and assembly teams, service and logistics hotlines and well-equipped training centers. In addition, our employees have a global presence and are familiar with all relevant local requirements, guidelines, and standards.

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