I am interested in enhancing my oil analysis program. I have equipment ranging from cnetrifugal compressors to rotary screw compressors to piston compressors to continuous stir mixer drives. My current program calls for the following OA Tests:
emmission spectroscopy
Laser Particle
viscosity
FTIR
Water (Crackle and Karl Fischer if needed)
TAN and/or BAN
Wear debris
My question is what good does FTIR do me? Am I wasting money on an expensive test?

Dear Mr.Ken,

FTIR is a very good instrument and not a time waste or money waste.It will give you the xerox copy of your oil.If you want to carry out Oxidation,Nitration,Soot etc......FTIR is one of the best in the field.

Ken,

I agree with the above comment. For many labs, FTIR is part of the test suite for oil analysis.

FTIR is definitely an essential part of the analysis program because it can provide a trend on the oxidation by products which eventually affects TAN & viscosity & wear debris.

I believe that most applications you mentioned are fixed plant related. You mentioned a number of compressor applications. Rotary screw compressors have high pressures and discharge temperature which can lead to varnish formation damaging bearings and restrict clearances. Small sump sizes places more demand on the fluid. FTIR oxidation will provide trends on oxidation by products (some of these species are not yet organic acids which FTIR will pick up due to the carbonyl groups), many of these species then go on to become weak organic acids, this is where TAN & KV & wear metals comes in useful.

Piston compressors can have small sumps, the lubricant is subjected to high thermal stress in the cylinder area. Again high temperature will lead to oil oxidation so FTIR is an essential part again to determine the trend in oxidative by products.

In centrifugal compressors, the lubricant is required to lubricate bearings, shaft & gears. The fluid in general suffers less oxidative stability. Typically a turbine oil with rust & oxidation inhibitors are used. It is critical that the lubricant does not form deposits or varnish on bearing surfaces due to small clearances. Deposits and varnish are one of the end result of oil oxidation. So FTIR again provides valuable data. In addition, some labs also perfom RPVOT on the turbine oil.

As for continuous stir drive mixers/agitators etc.. where temps are possibly 65C or less, FTIR can still provide valuable information on oxidation by products and trends. If it is part of the test suite for industrial gear oils, you might as well have the result to give a better overall condition of the oil.

It is relatively an inexpensive test as most labs have automated samplers with the FTIR instrument. The person diagnosing the results also gets a much better overall picture of the oil condition leading to a more meaningful diagnosis.

I donont think you are wasting your time ,FTIR will provide you with valuble iformation about oxidation , water content,sootand enable you to implement trending methodolgy easly.

save your money not worth buying one if you want send a out a few samples before buying and see if it shows anything for you IMHO the tests you do now are fine.

FTIR will show oxidation perhaps faster than your tests but I do not think worth buying one.
bruce