The key to successful CBM for any in-service lubricant is to obtain a representative sample of the lubricant for analysis. In the case of in-service lubricating grease, it is imperative to obtain a sample of grease that has been in the contact zone of the bearing, not just in the grease cavity.
There are two general cases:
- When possible, collect a sample of in-service grease from the contact zone in a bearing, gear, etc.
- When bearings are totally enclosed (electric motors, etc.), collect in-service grease during relubrication as the old grease is purged from the bearing.
In either case, collect grease in a clean container to prevent contamination. The sample container must be impervious to the grease and not absorb oil from the grease.