Prevention is always better than cure and using a proactive management approach to industrial gearboxes can deliver maximum planned availability and ensure that production down-time is minimised. Dave Brown, sales manager for Brevini UK looks at the skills and services required to deliver the optimum service at competitive rates.
Preventative maintenance is crucial in managing power transmission systems, especially when the application involves high value products or if the asset is located in a remote of difficult to access position. Identifying any early signs of wear, misalignment or bearing issues at the earliest opportunity, allows them to be resolved before they develop in to a full-blown breakdown, which can have huge cost implications.
Planned maintenance needs to be devised in such a way that regular inspections will identify potential problems and allow them to be resolved in a manner that causes a minimum of disruption to the application. These inspections can include vibration analysis, thermal imaging, lubricating oil analysis as well as videoscope inspection, which can identify abnormal contact wear patterns and internal gear damage.
The inspection report which is produced should identify any area for concern and also recommend a course of action to remedy any potential issues. For equipment that is hard to access or of a scale that makes removal very difficult, regular inspection is crucial because an unexpected failure can result in huge costs to repair or even replace the gearbox. A repair which is carried out during planned down-time will have significantly less impact on the application than one which is the result of an unforeseen failure.
This leads to the next step in the maintenance programme, which is recommended repairs, and involves a more detailed inspection usually performed in a workshop, but in some cases in-situ. During a planned shutdown, the drivetrain should be completely dismantled, cleaned and closely inspected for signs of wear, damage or misalignment and an appropriate action proposed to resolve the issue.
The use of crack detection is crucial in determining the condition of the gears and shafts, which may have been over stressed but continued to operate without failure so far. This scenario is more common in applications where the load applied to the gearbox varies significantly, especially in cases where the overload device may have been compromised.
One of the more common issues with drivetrains is being out of balance and this can result in a number of component failures if it is not resolved satisfactorily. As part of the process of reassembling the gearbox, it is important to check the balance of the assembled gear shafts. Failure to do this can result in significant vibration which can lead to catastrophic failure – a primary reason for the regular vibration analysis.
At this point a comprehensive inspection report should contain all of the issues which have been identified along with suggested remedial actions. For gearboxes which have been in service for a considerable time, it may be necessary to manufacture replacement components, but this should not pose any issues for the service centre. Rebuilding of the gearbox will include the replacement of all bearings and any other components which have been identified as beyond service life.
Reinstallation of the overhauled gearbox should include shaft alignment checks before the gearbox is returned to service. In some cases, where the gearbox was repaired following excessive vibration for example, continued condition monitoring can be maintained to ensure that the original issue has been resolved.
Brevini offers a range of services including repair, refurbishment and replacement for all types and manufacturers on units up to 15 tonnes. This includes a removal and reinstallation service and any redesign and up-rating that may be required, with all work is carried out by trained service engineers in accordance with its ISO9001:2008 quality system.
