Trending Grease samples from low speed Bearings

MaintenanceForums

I have a customer with an apron feeder where the head and tail bearings are rotating at less than 1 rpm. I am looking for a dependable predictive CM process to monitor the health of these bearings. Refer to my other post http://maintenanceforums.com/e...3&a=tpc&f=5891004322

Has anyone had an success extracting grease samples from a housing using some form of extraction port similar to what can be done with oil sampling from a gearbox. The apron feeder is used in an iron ore mining environment so removing the housing cap will not work due to air borne contamination

Any ideas would be greatly appreciated

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Registered Member

It's been my limited experience that grease does not become homogeneous like oil and that trending from grease samples is not reliable.

10/31/1410:52 AM

Registered Member

http://mrgcorp.com/grease-thief/

Get in touch with Rich Wurzbach at MRG to discuss your application/need. He's been on this site before, but I haven't seen him post in a long time. He is quite knowledgeable about grease analysis and collection and he developed the grease thief for collection grease samples.

Good luck.

10/31/1410:56 AM

Registered Member

sampling and analyzing grease is quite difficult because it will be difficult to sample (you do want a part of the grease that actually has been used in the bearing itself and has not been stationary within a cavity) and analyzing the grease after sampling also is quite difficult and of a very limited nature.

the cost of obtaining and analyzing a sample also can be prohibitive. personally i would not try to do a kind of trend analysis, because it is near impossible to get any meaningful results.

a easier way to monitor the bearings would be measuring vibration or temperature on a regular basis. that could lead to useful information about the "health" of the bearings and also give some information whether regreasing or adding a little grease might be advantageous.

11/7/146:20 AM

Registered Member

quote:
Originally posted by romke:
sampling and analyzing grease is quite difficult because it will be difficult to sample (you do want a part of the grease that actually has been used in the bearing itself and has not been stationary within a cavity) and analyzing the grease after sampling also is quite difficult and of a very limited nature.

the cost of obtaining and analyzing a sample also can be prohibitive. personally i would not try to do a kind of trend analysis, because it is near impossible to get any meaningful results.

a easier way to monitor the bearings would be measuring vibration or temperature on a regular basis. that could lead to useful information about the "health" of the bearings and also give some information whether regreasing or adding a little grease might be advantageous.

Hi Romke,

I understand the difficulties with trying to trend grease results the environment is extremely dusty so trying to prevent contamination would be almost impossible.
Vibration is not an option due to be slow speed, however temperature could be viable.

11/7/146:33 AM

Registered Member

quote:
Originally posted by Danny Harvey:
It's been my limited experience that grease does not become homogeneous like oil and that trending from grease samples is not reliable.

I have to agree with my friend Danny here. I've tried it two or three times and never got anything repeatable even when I sent in samples that I had taken at same time but different area on bearing (Lime Kiln once and brick oven once).
We did develop what we thought was a good check on the brick oven using an ultrasonic gun and just listening to the bearing. Couldn't develop a trend with db, but felt our ears were doing well with it.

D

11/7/147:57 AM

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