How routine maintenance can avoid a desaster
For a routine maintenance of large air coolers in a chemical plant our engineer is fixing the measurement equipment. The fan blades have a length of 5 meters, one fan has the weight of 1 ton. The coolers are installed on a gear, which is surrounded by a separate concrete ring. The gear is operated by a motor, installed outside of the concrete ring and connected with the gear by a cardan shaft lead through a hole.
Acces during operation is impossible and strictly forebidden.
Normally, we measure vibration with 2-3 mm/s. This time, vibration with 20 mm/s have been recorded.
After starting the measurement our engineer has doubts with regards to the accurateness of the figures: Vibration values with 20 mm/s are recorded – that would be more than alarming.
However, the measurement setup is correct! An optical inspection through the hole with the cardan shaft provides a view into the inner circle and shows the distaster!