ProLink condition monitoring system keeps a check on stacker crane trolley bearings in cold and frozen storage areas
Fruit processing company Zentis has taken delivery of a ProLink condition monitoring system from Schaeffler to keep tabs on the operation of trolley bearings on stacker cranes, which operate in cold and frozen storage areas.
Based in Aachen, Germany, Zentis producies jams and fruit preparations for the baking, confectionery and dairy industries. The site uses large stacker cranes for storage, transfer and retrieval operatings. In order to monitor the large and difficult-to-access moving components in the cold and frozen storage areas and to avoid unplanned downtime, the logistics team at Zentis was looking for a predictive maintenance system.
Zentis had previously implemented Schaeffler’s SmartCheck condition monitoring devices on gearboxes and cable reels to monitor the health of a critical pallet lifter. The devices have helped to prevent unplanned downtime and optimise production. If the pallet lifter fails, the first production stoppages occur around two hours later. The SmartCheck devices measure the vibration, speed, temperature and imbalance of various rolling bearings in the gearbox, as well as the gear teeth/mesh. This has enabled an early warning period of several weeks which allows Zentis to carry out repairs and remedial action as part of planned maintenance work, thereby avoiding costly unplanned downtime.
A cold challenge
In the cold and frozen storage areas at Aachen, a different kind of system was required as the stacker cranes constantly move around the 30-metre tall racks in different directions. The trolley bearings, in particular the non-driven bearings, are highly stressed. The fact that constant measuring conditions do not exist during regular operation posed an even greater challenge. In addition, temperatures in the frozen storage area are as low as -20°C, which presented yet another challenge for the new measuring system, for example, how to attach the sensors to the measuring points.
To monitor the stacker cranes, a Schaeffler ProLink CMS and five sensors (bearing guards) were installed on each stacker crane unit. In order to perform meaningful vibration monitoring, the original measurement concept had to be changed in the multi-channel CMS. Schaeffler achieved this by breaking down the short, slow travel times into many short measurements. Any extreme impacts could then be determined from these measurements.
To solve the temperature challenge in the cold storage area, the ProLink CMS was installed in the switch cabinet. In the frozen storage area, the ProLink system was placed in heated control cabinets that escort each stacker crane run. The sensors were attached to the measuring points using a special, cold-resistant adhesive compound.
The implementation of the ProLink CMS has benefitted Zentis in several ways. With early warnings of any change in the condition of the stacker crane trolley bearings, the site has also seen an improvement in the planning of maintenance activities, as well as improved safety and transparency. The ProLink CMS is also fully integrated into the site’s own control system.
According to Michael de Ben, Head of Internal Logistics at Aachen, the ProLink CMS monitors heavily strained moving components on the stacker cranes that, due to their size or mounting position, cannot be repaired promptly in the event of an unplanned malfunction.
“By using bearing guards, the vibration pattern of this equipment can be permanently observed and any deviation can be detected at an early stage. In this way, the ProLink CMS makes a crucial contribution to safeguarding the production supply at Zentis in Aachen,” he says.