Dear All,

Some equipment users had experienced gum formation on hydraulic oil equipments. Important point can be the this hydraulic oil is also used for lubrication oil. In our system we are also using the same kind of oil for both purpose (lube & Hyd) from common oil tank.

I wcould not find a test method for gum test for oil(s). If somebody has experienced & know about the testing for the concern please let me know the detail.

Thank you very much

Hi,

To check for varnish formation in lubricants can be very difficult,
we are more inclind to check for contaminates that may catalyse varnish formation in the lubricant and if found remove and usually the fluid degradation reduces to an acceptable level.
The filters can hold the info of why this is occuring,
section the used filter and remove a 50X50mm peice of undisturbed used filter media, solubulise the debris off the media and examine by microscope to view the contaminates and the clues may be there.
If no evidence there then examine for electrostatic discharge in the filters but this last event should be unlikely as you say several customers so we would expect more likely a common contaminate from the environment to be the cuprit.
The "Blotter Test", drop oil on the blotting paper and compare with same test with new oil and compare and the varnish potential should be deposited, unfortunately we have limited experience with blotter exam as we look with the microscope, I think "Circoil" had a "blotter test" for this but not sure if correct name

Speaking of the blotter spot test, does anybody know where I can obtain a comparison chart? It is an excellent "on the go" test but without the proper experience in identifying certain elements of the test, I find I don't get the most out of it.

There is a test designed specifically to determine the varnish potential of lubricants called Quantitative Spectrophotometric Analysis (QSA). It is much more sensitive then the blotter test and has been shown to have a direct correlation to varnish formation. This test is usually combined with a gravimetric patch test.

Analyzing filter media as suggested by RRTECH is also an excellent way of detecting the presence of degradation by-products and other contaminants, although it cannot determine the varnish potential of the lubricant.

Can you please explain in detail the test procedure and equipments/ instruments in volved in this test please ?
V.S.Dave

quote:

Originally posted by Greg Livingstone:
There is a test designed specifically to determine the varnish potential of lubricants called Quantitative Spectrophotometric Analysis (QSA). It is much more sensitive then the blotter test and has been shown to have a direct correlation to varnish formation. This test is usually combined with a gravimetric patch test.

Analyzing filter media as suggested by RRTECH is also an excellent way of detecting the presence of degradation by-products and other contaminants, although it cannot determine the varnish potential of the lubricant.

Contact Analysts Inc. for more information on the QSA test: Analysts Inc.

MC,

Check the proceedings for the 2 previous Lubrication Excellence conferences, Dr. Esteban Lantos from Laboratorio Dr. Lantos in Argentina, presented paapers regarding test.