I recently started a predictive maintenance program in a brick plant with very poor dust control. For years it has been their practice to grossly over-grease their bearings to protect from the abrasive dust- a practice which may have accelerated some of the premature bearing failures they have experienced. Many of the bearing seal systems have completely failed allowing for fairly free flow of lubricant through the bearing.

I have debated the wisdom of lubricating chain and sprocket drives in rock quarries before and found that many plants choose to leave them unlubricated because they believe that the grease captures the dust and leads to even quicker wear.

Any thoughts on the subject of lubrication in such an environment would be greatly appreciated.

Any opinions

1.) Dry chains are better but should be lubricated with dry lubricants. You can use a motorcycle lubricant and then spay graphite as the oil can penatrate and the graphite can create a dry lube chain.
2.) It sure would be nice if motor manufactures would allow grease in at the bottom (they do) and exit ~half way up with a vented plug.

Once a motor's lube seal has been pushed hydraulically then the bearing can't get enough grease and premature failure is the result as is a motor full of grease.

Danny,

I am in the same position as you are, starting a PdM program in a dusty construction materials plant.

I believe that overgreasing occurs when a lube tech cuts the greasing interval by factor of, say, 2 due to a dusty or high temperature operating conditions but still pumps in the same amount of grease suggested for a perfect one. Obviously this leads in the best case to a full cavity (if there is a drain plug ) or, in the worst case, both bearing and cavity. On the other hand, by cutting the amount of grease also by factor of 2 he may actually run into undergreasing situation as these relationships are not linear. So the amount and interval of relubrication has to be determined experimentally in each individual case.

ignore the previous email - sent by accident.
how do I delete it ?

David G send me your email address & I'll send you an article i have which I ciopied from the net BUT don't remember the sources
regards
Glenn
Halyburtong@onesteel.com

We don't have much contamination problem. Just thinking out loud, in addition to overlubrication, contamination is another big killer of bearings. I would think proper techniques to ensure cleanliness during regreasing are even more critical when greasing machines in a dirty environment.

Such techniques might include cleaning the machine fitting, pumping a dab of grease from the gun and wiping off that dab before just before you connect the gun to the machine. Use suitable clean lint-free cloth for wiping. At least that's what I'm remembering.