Air flow measurement for ventilation control in road tunnels 

Air flow measurement systems TMS2000 are specifically designed for working under conditions prevailing in road tunnels. In the driving area there are only robust mechanical sensors made of stainless steel, the signal processing electronics is located in a separate control room.

The high-resolution measurement allows continuous blower control and, thus, an effective optimization of power consumption of the fans. Our devices have been successfully used in world longest tunnels (e.g. the Gotthard in Switzerland or Plabutsch in Austria) or shorter tunnels (e.g. University in Düsseldorf, Germany).

Measurement is based on high-precision pressure measurement using special and differentially working Pitot tube sensors (DPS) which results in accurate flow measurement of the air through the tunnel.

This provides essential and partially unbeatable advantages:

• Robust sensors made of stainless steel.
• No moving parts.
• In the driving area there are no active electronic components.
• The measuring system is practically maintenance-free (recommended inspection interval – 5 years).
• Excellent measurement is still guaranteed even in case of fire (available for operating temperatures of up to 1200 °C).
• High resolution of less than 0.1 m/s in both flow directions.
• Information on flow rate through the tunnel cross-section gives precise flow measurement without any impact of road traffic.
• Optional calibration by our accredited test rig installation for air flow (ISO 17025).
• An absolute zero-point stability thanks to pneumatic Autozero system
  (automatically repeating "zeroing" of the deltaP measuring cells).
• Absolute air pressure measurement (barometric pressure) is already included.
• The Pitot tube sensors protrude only for approx. 40 cm into the driving area.
• Very easy dismounting of the deltaP Pitot tubes without tools during periodic cleaning of the tunnel walls.

Measuring method