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By providing online condition monitoring and training, FAG IndustrialServices is helping manufacturers in the cement, mining and quarryingindustries to eliminate unscheduled shutdowns and avoid costly repairsto critical rotating plant and machinery.
By investing in online condition monitoring systems to automatically detect early damage to gearboxes, cement manufacturer Spenner Zement has prevented unplanned downtime and avoided costly repairs to transmission gears and gearboxes at its cement mill in Erwitte, Germany.
Spenner Zement produces a range of cement, lime and dry mortar products. The company alsodevelops disposal concepts for different industry sectors whose wasteproducts can be used for secondary raw materials and fuel. The company operates several cement mills (tube mills) at its Erwitte site.
Back in 2002, Spenner faced a production problem on one of its cement mills at Erwitte. One of the tube mills had to be shut down for three weeks because of damage to a gearbox that was driving the mill. Atthe time, the three-stage gearbox was being monitored by a temperaturesensor, which failed to give Spenner’s maintenance team enough warning of damage to the gearbox.
The gearbox damage and subsequent failure not only resulted in three weeks of unplanned downtime on the tube mill, but also resulted in costly repairs, which included a completely new shaft and refurbishment of parts of the gearbox housing.
Spenner then called in experts from FAG Industrial Services (F’IS),the maintenance and condition monitoring company within The Schaeffler Group, to help eliminate any future unplanned stoppages to its tubemill.
F’IS recommended its online vibration monitoring system,FAG DTECT X1, along with four, permanently-installed sensors positioned on the main gearbox and reduction gear. Three sensors were installedon the main gearbox to monitor the gear bearings and gear mesh, withone sensor installed at the reduction gear to monitor gear rim and pinion condition.
In addition to installing the FAG DTECT X1 system and sensors, F’IS also provided three months’ vibration monitoring training. Spenner maintenance engineers were trained to analyse the condition monitoring data and are now capable of monitoring and analysingthe data on their own.
In 2004, around 18 months after installing the new condition monitoring system, the FAG DTECT X1 system detected damage to the gear teeth in the gear mesh. Initially, yellow alarms were displayed on the system, followed by temporary red alarms, indicating potential serious damage. Visual inspection from Spenner engineers confirmed that tooth damage had occurred in the second stage gears. The gearbox was subsequently replaced during the next scheduled shutdown period, without causing any disruption to production. Had the tooth damage been left undetected, damage to other parts of the gearbox may have occurred, causing costly repairs and further delays to production.
In 2006, Spenner equipped another two of its cement tube mills at Erwitte with FAG DTECT X1 systems. Five sensors are installedon each system, with three monitoring the vibration on the rolling bearings and the gear teeth. The other two sensors monitor vibration at the reduction gear bearings, girth gear and pinion.
All data istransmitted directly to Spenner’s central control room at the plant, automatically triggering an alarm if deviations from pre-set parametersare detected. Although several Spenner engineers are now fully trained to analyse the collected data, when initial signs of complex problems are detected, data can be emailed direct to F’IS experts who can carry out in-depth analysis on the data and recommend the appropriate action to be taken.
By analysing the data sent to them, F’IS experts not only detect the problem, but also can pinpoint the damaged component. For example, the type of damage and how quickly the damage progresses, provides valuable clues for maintenance planning teams. Thanksto early detection, special replacement parts can be purchased in time and replacement can be carried out during routine, planned maintenance intervals.
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