Air flow measurement by differential pressure
The
air flow monitoring system measures the longitudinal air flow at 2
points in a tunnel cross section. The method allows to optionally remove
all electronic components from the tunnels driving area to maintain a
measurement also under high temperatures.
Two differential pressure pitot tubes are mounted on opposite tunnel
walls. Measuring the air flow at 2 points allows to calculate a
representative average air flow over the tunnel cross section.
An air flow in the tunnel generates a dynamic pressure on the side of
the pitot tube facing the flow of air while on the other side only the
static pressure is present. The measured differential pressure is used
to calculate the air velocity under consideration of the also measured
temperature. The values of the 2 measuring points are then averaged.
Outputs available: air velocity, direction of air flow, air temperature.
Features
- Robust air flow monitoring system based on high-precision differential pressure measurement
- 2-point mesh
- Automatic zeroing of differential pressure transducers
- Touch evaluation and control unit to display measured values, status and set parameters
- Connection to tunnel control system by RS-485 MODBUS RTU, optionally by analogue outputs and relay contacts.
Advantages
- Specifically designed for tunnels
- Easy installation and setup
- Long term stability by automatic zeroing
- Measurement possible at high temperatures
- Corrosion resistant against aggressive tunnel atmosphere
- Minimised spare requirements
- Extremely low maintenance requirements
