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D-FL 100 Volume Flow Measuring System

Suitability-tested and certified impact pressure system to measure velocity and volume flow of dry flue gas or process gas in pipes or ducts.


Suitability-tested and certified impact pressure system to measure velocity and volume flow of dry flue gas or process gas in pipes or ducts.


  • Reliable measurement of the gas velocity even at high temperatures
  • Calculation of volume flow at standard conditions
  • Certified, cost effective measuring system
  • Versions with or without counter-support and for point measurement
  • Extremely low maintenance, maintenance interval 6 months
  • Convenient operation via remote access with web Interface

Your Benefit

  • Certified for official emission monitoring
    Type approved according to EN 15267-3, certified versions for EX environments available
  • Precise velocity and volume flow measurement under difficult conditions
    Averaging pitot tube with bore holes placed according to the reference method ensures optimum comparability with the reference method
  • Space-saving and easy installation
    One-sided Installation without alignment available for small stacks
  • Low risk of failure
    Option remote mounting with no electronic parts on the hot side allow operation with no purge air requirement even at high flue gas temperatures
  • Suitable for harsh flue gas conditions
    Ruggedized probes made from special materials available for extremely high temperatures or aggressive flue gases
  • Reliable emission monitoring
    Automatic back purging option ensures reliable measurements and a long lifetime for flue gas with high dust content


Suitable for velocity and volume flow measurement

  • Volume flow measurement at high temperatures
  • Plants with large or small flue cross-sections
  • Volume flow measurement at high pressure


  • Plants requiring official approval acc. to IED 2010/75/EU
  • Emission trading of green house gases GHG acc. to 2003/87/EG / MRR
  • Power industry
  • Incinerators with dry fluegas
  • Waste incineration
  • Cement industry
  • Crematories
  • Process monitoring
  • ATEX applications

Technical Data

Flue gas type Air, flue gas, non flammable process gas
Flue gas temperature Above dew point,
up to 450 °C standard,
up to 1000 °C option
Flue gas dust concentration 0 … 30 mg/m3, type 1 (24x22mm) without backpurge
0 … 100 mg/m3, type 2 (54x50mm) without backpurge
0 … 150 mg/m3, type 3 (100x90mm) without backpurge
Inner stack/duct pressure (relative to ambient pressure) -50 … +50 hPa
Flue gas relative humidity 0 … 95 % RH, non-condensing
Flue gas flow velocity 3 … 50 m/s
Stack/duct inner diameter 0.5 … 10 m

Measuring principle Measurement of ram pressure / differential pressure with a dual-chamber-probe
Measuring principle description The probe has two separate chambers between which the flow builds up a differential pressure. The evaluation unit determines the gas velocity and the volume flow (norm conditions or standard conditions) from the differential pressure, taking into account gas temperature and gas pressure
Conformities IED 2010/75/EU
13., 17., 27., 30. BImschV
TA Luft
EN 14181
EN 15267-1, -2, -3
DIN EN 16911-2
Certificates CE, QAL1 (DIN EN 14181 / DIN EN ISO 14956 / DIN EN 15267-3), MCERTS, EAC Gost Ex Zone 2
Measuring location In-situ, non-contact. Mounted at stack, measurement across the stack, half duct or single point, probe is in contact with flue gas
Measuring path length 0.4 … 8 m
Measuring angle 90° -4° relative to the flow direction
Self-check, protective functions Automatic internal self-test
System components D-FL 100 DS probe
D-FL 100 DDM-H differential pressure transmitter
D-FL 100 UH valve
D-FL 100 A adaptor
D-FL 100-20 evaluation unit
D-ISC 100 operating unit or D-ESI software
D-FL 100 ADM-H absolute pressure transmitter (option)
D-XT temperature transmitter (option)

Physical measuring value Ram pressure / differential pressure
Derived measuring values Flow velocity, volume flow at operating conditions or normalized
Measuring range gas velocity 3 … 50 m/s
Output range gas velocity Freely programmable
Measuring range volume flow 0 … 3000000 Nm3/h
Output range volume flow Freely programmable
Measuring range temperature 0 … 600 °C
Output range temperature Freely programmable
Resolution 0.1 m/s
Combined standard uncertainty acc. to QAL1, DIN EN 14181 0.71 m/s
Integration time 1 … 180 s, freely programmable
Process connection Mounting tube with flange,
DN40 PN6 (system 1), tube ID = 43.1 mm, OD = 48.3 mm,
DN65 PN6 (system 2), tube ID = 70.3 mm, OD = 76.1 mm,
DN100 PN6 (system 3), tube ID = 107.1 mm, OD = 114.3 mm,
other on request
Digital interfaces RS 485 Modbus RTU, bi-directional communication, USB (Service)
Analog outputs 1 x 4 … 20 mA, 400 Ohm, isolated, assignment parameterisable
Digital outputs 2 x contact NC/NO, permissible load 60 VDC / 30 VAC / 0.5 A, function can be assigned. Typically: maintenance, failure
Power supply Sensor supply voltage 24 VDC ±10 %, 0.5 A (standard)
90 … 264 VAC, 48 … 62 Hz (option)
Operation D-ISC 100 universal operating unit
D-ESI 100 software, requires Windows-PC
Ambient temperature (operational) -20 … +50 °C standard
-40 … +60 °C option
IP protection class (IEC 60529) IP65 (standard)
IP20 (evaluation unit M)
Dimensions (HxWxD) Evaluation unit A/P: 231 x 160 x 105 mm
Evaluation unit M: 62 x 90 x 54 mm
Probe 1: 24 x 22 x 400 … 2000 mm
Probe 2: 54 x 50 x 2000 … 4000 mm
Probe 3: 100 x 90 x 4000 … 8000 mm
Weight 1 kg (evaluation unit only)
Material Housing evaluation unit: Polycarbonate RAL 7035, fire class B1 (UL 94 V0),
Process parts: Stainless steel 1.4571 (316 Ti)

Process connection DN40 PN6 (system 1), tube ID = 43.1 mm, OD = 48.3 mm,
DN65 PN6 (system 2), tube ID = 70.3 mm, OD = 76.1 mm,
DN100 PN6 (system 3), tube ID = 107.1 mm, OD = 114.3 mm
Dimensions (HxWxD) System 1: 130 x 120 / 240 mm, other on request
System 2: 160 x 240 … 700 mm, other on request
System 3: 210 x 240 … 800 mm, other on request
Material Stainless steel


Universal display and operating units

The universal operating unit  Opens internal link in new windowD-ISC 100 allows the connection of several DURAG devices. It allows parameterization and maintenance of all connected devices via integrated keypad or a connected PC and also supports remote access via intranet or internet connection.

Additional Accessories

We offer various accessories such as weather protection covers for your sensor, mounting flanges and so on to fit your application and to have all components from one source.



Product overview emission monitoring / DE (4 MB)
Product overview emission monitoring / EN (4 MB)
Guidance book EU regulations / DE (4 MB)
Guidance book EU regulations / EN (3 MB)

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