Extraction Fans in Highway Tunnel
A series of ventilation fans, placed at regular intervals throughout a highway tunnel, needed monitoring. Cabling of wired condition monitoring units would be a difficult, time-consuming, and expensive process due to the length of the tunnel spanning multiple kilometres.
Using the WiFi coverage present in the recently built tunnel, Agen installed a remote vibration monitoring system. Vibration sensors were programmed to turn on according to pre-set traffic and weather conditions controlled by other environmental sensors.
When switched on, sensors took measurements every 15 minutes. When dormant, recordings were taken only every two hours (to preserve battery levels). Once configured to these dynamic criteria, sensors remembered the rules and took measurements even if the wireless network became temporarily unavailable.
One of the fans showed high levels of vibration upon start-up. An automatic alert was sent via email and a technician was dispatched to investigate the problem, which was caused by loose bolts. The ramp-up speed of the fan when starting passed the resonance frequency, triggering the early warning system.
Had the condition monitoring system in place been unable to take dynamic measurements, this type of “fan start-up” problem may never have been discovered, and the situation could have worsened. As it were, the problem was fixed before an issue could arise.