wind turbines


Tunnel Air Flow Measurement system

Categories: Weather & Meteorological Instrumentation, Road Sensors,

JES / Durag Group offer an Ultrasonic Airflow measurement system to measure air speed and direction to control tunnel ventilation. The system comprises two D-FL 220T M sensors and D-TB 100T Terminal boxes and an optional JES c/OPS Touch operating unit.


  • Precise ultrasonic air flow measuring system based on different transition times of ultrasonic pulses
  • Measurement of average air-flow over the whole tunnel cross section
  • Sensor setup via service interface
  • Suitable for tunnel cross sections up to 18 m (Measuring path up to 25 m)
  • Connection to tunnel control system either via analogue out-put and relays or via RS-485 MODBUS RTU
  • Visible LEDs to indicate sensor status
  • Optional, remote touch operation unit to display measured values and to modify parameters

System Set-up

  • Two sensors (master & slave) with mounting clamps mounted below the tunnel ceiling in an angle of30° to 60° to the tunnel axis
  • Terminal box for master to connect the power supply and the connections to the tunnel control system and the slave
  • Terminal box for Slave
  • Optional remote touch operating unit


  • The air flow monitoring system measures the air flow based on different transmission times of ultrasonic pulses sent in one or the other direction. This cross section measurement delivers the average air speed more reliable and meaningful than methods that measure only one or two points on the tunnel wall.
  • Two sensors are mounted below the tunnel ceiling, cross section with an angle of 30° to 60° (usually 45°) such that a vector component of the air flow overlaps the direction of the ultrasonic sound pulses exchanged by the two sensors.
  • Air flow in the tunnel influences the transition time of the pulses between sender and receiver. Based on the difference in transition times of ultra-sonic pulses sent in one or the other direction the measured values are calculated.
  • Measured values are air speed, air flow rate, direction of air flow and air temperature.


  • Specifically developed for application in tunnels
  • No control unit required
  • Easy configuration
  • Corrosion resistant against aggressive tunnel atmosphere
  • Sensors can be replaced quickly with no tools and no re-alignment required
  • Minimised spare requirements
  • Extremely low maintenance requirements


Tunnel & Roads Transport

Weather & Meteorology

Rasheeq Zaman

Rasheeq Zaman

National Sales and Marketing Manager

Get in touch for more information...