Pulp & Paper

In comparison with other machine types, a paper machine is characterized mainly by the following features:

• 1 machine with considerably large dimensions
• 500 or more individual roller-bearings
• Very low rotational speeds in some sections
• Speed-controlled drives
• Hostile operating conditions due to high temperatures and humidity
• Difficult accessibility to the measurement points
• Bearing breakdown results in a complete shutdown of the entire machine

The most cost-effective solution is an integrated combination of on-line/off-line monitoring, with on-line monitoring for the paper machine itself and off-line monitoring mainly for the auxiliary support machines.

For the paper machine, condition monitoring by a multiplexed operation is adequate, with the wet section and the dryer section having their own separate data acquisition cycle times. This ensures that the shortest data acquisition cycle times are achievable.

For early fault detection the measurement types Bandpass (bp) in velocity and acceleration units, and CPB-spectrum (cpb) – the most practical being 23% - also in velocity and acceleration units should be used.

For failure analysis the auto-spectrum (as) should be in velocity and the selective envelope detection (SED) in acceleration units.