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July - August 2022
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OIL FLUSHING
Pros & Cons
e pros and cons for both discussed methodologies are listed here:
INSOLUBLE CONTAMINANTS MEASUREMENT
Gravimetric Method (mg/liter) Utra-Centrifuge
0 to 50 0
51 to 80 1
81 to 120 2
121 to 150 3
151 to 175 4
175 to 200 5
201 TO 280 6
281 to 360 7
>360 8
METHODOLOGY PROS CONS
Gravimetric Analysis
Relatively cheap tools Time consuming
Manually operated procedure Results are based on weight, hence cannot be misinterpreted
Exposure to kerosene and petroleum ether
Centrifugal Method
Automated procedure Expensive equipment
Minimum manual input required and time-saving Scale rating is judged visually and is prone to human error
Can test multiple samples simultaneously Prone to maintenance issues
No chemicals needed
Results and Discussions:
ere were 305 lube oil samples from hydraulic, transmission, refrig-
eration and synthetic turbine oils, which were analyzed simultaneously
for insoluble contamination by both gravimetric and UC methods. e
results are compatible and show linearity by both methods.
e comparison of insoluble contaminants in the analyzed 305 lube
oil samples showed that the results by gravimetric method vary from
2 ppm to 414 ppm, whereas UC values lie between 0 and 8. ree
samples deviated from linearity, but they were positive in the crackle
test and had high water content. e results of these three samples were
not considered in determining the equivalency of values obtained by
both methods.
e equivalency of contaminants/insoluble determined by both
methods was critically analyzed and classified as per the graph in Figure
3 and Table 2 :
Table 1: Pros and Cons of Filter Test vs. Ultra-Centrifuge Test
Table 2: Comparison of Filter Test vs. Ultra-Centrifuge
Figure 3: Comparison of Filter Test vs. Ultra-Centrifuge
