Paper Machine Lubrication (housed roller bearings)

Jim,
Most grease in a housing that is not in close proximity to the load zone will normally surface harden after either prolonged exposure to the bleed/replenish cycle or from simple surface hardening (skin effect) from exposure to the air. If I understand your circumstances you are concerned that when you add more grease into the load zone while the equipment is in operation it will not purge either from the labrynth or the purge plugs?? IF you use the simple dn value of ID in mm X RPM and if that number comes in at less than 150,000 then most of the bearing manufactures will allow you to completly fill the housing with grease. By filling the housing you will cause the existing hardened grease to be displaced somewhat. However the most importand thing is that you will have "new" grease in the load zone. All of the rest of the grease in the housing (except that in very close proximity to the load zone and that which slumps back into the load zone, is filler ONLY.
The other option is to wait until the next outage and open the housings and vacuume out the used grease.
regards.....

I think it may be worth a try to put some oil (same visc. as in your gease) into the housing to soften it. Then purge bearing while shutdown. I think you also need to increase the greasing frequency or switch the type of grease you are using. I had grease hardening in my felt rolls dure to the temps, it was oxidizing. Switched to a PAO base oil grease (Mobil SHC PM)and had much success with it. Grease no longer is hardened when purging. I purge bearing every shutdown about every 4-8 weeks. Hope this helps.

I just wanted to follow up and thank dshiel & Allen Wallace for their replies. I am new to this Paper Mill and am introducing common pm tasks, such as purging press roll bearings on a monthly basis. In the past the press rolls have never been purged, "knowingly". In a paper machine environment purging through a labrynth seal is the last option, especially on press rolls. This purged grease has the potential to fall of to the sheet which has the potential to cause culled paper among other issues. We planned on introducing a light weight hyd oil for a short duration but will be purging the bearing prior to shutting down the paper machine. This will assist in reducing condensation in the housing & assure we are purging at operating temperatures. I was hoping to get concensus on this procedure(thanks dshiel). These bearings are lubed with a Chevron product which has benefited this mill.
Thanks again,

Jim