Hello everyone,
For years now we have been sampling our lube oil and seal oil reservoirs to our compressor to assess the bearing condition. My question is , is this enough? I mean should we be taking more samples along the oil stream, for example, our oil pump takes the oil from the reservoir and pumps it through a filter then to a cooler before entering the bearings, someone suggested that we take samples before the filter, which I can't make any sense of, what value will sampling before the filter have?

Get them off the down side of the bearing and when doing samples from the reservoir also take a scraping from the bottom.

If fitted with eddy current probes make a record of the DC component along with vibration data.

I think, it doesn't matters whether you take the sample up or downstream of filters. The thing that matters is whats the condition of lube thats coming from the bearings, i.e. oil return line from bearings. Thats the best location for oil sampling.

Answering to your question, thats not enough, we also need to monitor the bottom sedimentation condition of the reservoir.

Since large reservoir lubes are only replaced, based on its condition, therefore one should also monitor the bottom condition. The best way is to install BS&W sight glass and periodically drain small quantities to visually inspect the oil condition.

Regards,
Mohammad

Just a thought.
Is it not the purpose of the filter to remove contamination? The filter can not tell the difference between dirt and gear or bearing metals? Depending on the micron and beta rating you could be removing most of the metals you are looking for from machine components? Sample before the filter then you are getting the oil from the componemts your are wanting to find fault. After the filter your are finding the performance of the filter?

What is the beta and micron rating of your filter? How large are the reservoirs?

I concur with Sam, if it is possible to get the sampling downstream of the bearing, this would therefore provide you useful information about your bearing.

My Warm Regards,