Hello Kevin,
There are several "charts" out there giving sound engineering advice, on both replenishment frequency and replacement intervals. Generally they suggest that you can replenish 3 or 4 times before re-packing is required. Just to be clear you are talking about dissesembly, cleaning and repacking and reassembling as being repacking correct??
We used to take off the bearing covers, check the diametrial clearance, tighten the adapter sleeve if required, clean up around the bearings add some fresh grease and close up the cover. Lots of failures from maintenance intervention. Re-tightening the adapter (what were we thinking??) Opening the cover in very dirty conditions. Cleaning out the inside of the bearing housing (forcing the used grease back into the load zone.) All very bad for the bearing things. We don't do any of that anymore. What we do do is to insure that the bearings are purged by pumping grease into the bearings through the W33 groove while the bearing is rotating. This takes the wear particles away from the load zone where they can do harm. Vibration analysis tells us when a bearing is failing and it can be planned and scheduled.
You have to determine the criticality these fans have to the process and create a maintenance plan to deal with the indicators. What are the concequences? What are the bearing sizes and rpm's? Ambient temperature and operating temperature?
If your bearings are <150,000 dn (ID in MM X RPM) and you have either labrynth seals or RLS installed for dirt exclusion then you can "safely" relubricate your bearings until the proverbial cow comes home. By either stoping the generation of wear particles or removing them as soon as possible then you will increase the life of the bearings. Instead of re-packing I'd suggest you consider re-lubricating as per the avaliable charts. One source of these types of charts in the SKF Bearing Maintenance Handbook.
regards.....
