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.


  • 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 typeAir, flue gas, non flammable process gas
Flue gas temperatureAbove dew point,
up to 450 °C standard,
up to 1000 °C option
Flue gas dust concentration0 … 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 humidity0 … 95 % RH, non-condensing
Flue gas flow velocity3 … 50 m/s
Stack/duct inner diameter0.5 … 10 m
Measuring principleMeasurement of ram pressure / differential pressure with a dual-chamber-probe
Measuring principle descriptionThe 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
ConformitiesIED 2010/75/EU
13., 17., 27., 30. BImschV
TA Luft
EN 14181
EN 15267-1, -2, -3
DIN EN 16911-2
CertificatesCE, QAL1 (DIN EN 14181 / DIN EN ISO 14956 / DIN EN 15267-3), MCERTS, EAC Gost Ex Zone 2
Measuring locationIn-situ, non-contact. Mounted at stack, measurement across the stack, half duct or single point, probe is in contact with flue gas
Measuring path length0.4 … 8 m
Measuring angle90° -4° relative to the flow direction
Self-check, protective functionsAutomatic internal self-test
System componentsD-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 valueRam pressure / differential pressure
Derived measuring valuesFlow velocity, volume flow at operating conditions or normalized
Measuring range gas velocity3 … 50 m/s
Output range gas velocityFreely programmable
Measuring range volume flow0 … 3000000 Nm3/h
Output range volume flowFreely programmable
Measuring range temperature0 … 600 °C
Output range temperatureFreely programmable
Resolution0.1 m/s
Combined standard uncertainty acc. to QAL1, DIN EN 141810.71 m/s
Integration time1 … 180 s, freely programmable
Process connectionMounting 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 interfacesRS 485 Modbus RTU, bi-directional communication, USB (Service)
Analog outputs1 x 4 … 20 mA, 400 Ohm, isolated, assignment parameterisable
Digital outputs2 x contact NC/NO, permissible load 60 VDC / 30 VAC / 0.5 A, function can be assigned. Typically: maintenance, failure
Power supplySensor supply voltage 24 VDC ±10 %, 0.5 A (standard)
90 … 264 VAC, 48 … 62 Hz (option)
OperationD-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
Weight1 kg (evaluation unit only)
MaterialHousing evaluation unit: Polycarbonate RAL 7035, fire class B1 (UL 94 V0),
Process parts: Stainless steel 1.4571 (316 Ti)
Process connectionDN40 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
MaterialStainless steel

The universal operating unit D-ISC 100 can be connected to several DURAG sensors. It allows parameterization and maintenance of all connected sensors via the integrated keypad or a connected PC and also supports remote access via intranet or internet connection.

Opens internal link in new windowD-ISC 100

  • Owing to the working principle, the accuracy of the measurement depends on the installation type and -location, the flow pattern and on the accuracy of the reference method.
  • Subject to technical modifications.




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 parameterisation and maintenance of all connected devices via integrated keypad or a connected PC and also supports remote access via intranet or internet connection.


Our  Opens internal link in new windowD-ESI Service and Parameterisation Software  assists you to manage all your DURAG sensors connected in one network system via a uniform graphical Interface.


Please contact your sales representitive for more Information.

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.

Please contact your sales representative for further information.