Vibration monitoring keeps tunnel operating
May 1st 2005

Amultichannel monitoring system from Monitran is used by Mersey Tunnels to measure vibration levels on the fan ventilation system of its Kingsway Tunnel.

There are eight sets of vibration systems with both extract and blow. Four of the sets are on standby. Each system uses fans with blade diameters of up to 3.5m.

Carbon monoxide levels and smoke density are monitored manually and, when excessive levels are detected, an operator can change the fan speed. Each fan is driven through a Radicon gearbox, the bearings of which are monitored for vibration levels.

When these become excessive, maintenance engineers can switch to standby fans while they carry out repair work.

Fan systems are in robust casings so components cannot be seen or accessed easily. A Monitran vibration sensor is fitted at each point on the eight fan systems, giving continuous, simultaneous readings for the entire tunnel.

Sensor signals are cabled into the multichannel MTN 6000 system housed in an enclosure. It provides sensor excitation, signal conditioning, level indication and pre-set alarm triggering via relay units.

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