"Which types of oil sample bottles are best? Our lab provides sample bottles, but we are wondering if you could recommend a specific size or material?"
Proper oil sampling is essential for an effective oil analysis program. Without a representative sample, further oil analysis efforts will be futile. Clear, ultraclean sample bottles are considered the best because of how clean and easy to inspect they are.
The sample bottle size should be based on the type of sample fluid as well as the number and types of tests to be conducted. For most standard oil analysis tests, oil samples are taken in a 100- or 120-milliliter bottle. For advanced or exception tests, a 200-milliliter or larger bottle may be required.
An example of when a larger sample might be necessary would be for hydraulic fluid testing, especially aviation hydraulic fluid. Sample bottles can also come in smaller sizes for other applications.
When choosing an oil sample bottle, first talk with your oil analysis laboratory. Ask if the lab provides or recommends sample bottles. In addition, find out if the bottles are subjected to testing, as per ISO 3722. You then must determine the cleanliness requirements for your samples.
There are a variety of opinions on how clean a sample bottle needs to be. Most oil testing equipment is sensitive enough to detect the difference between ISO clean (100 particles greater than 10 microns per milliliter), superclean (10 particles greater than 10 microns per milliliter) and ultraclean (1 particle greater than 10 microns per milliliter) bottles.
The only reason to use a more expensive superclean or ultraclean bottle would be if the additional particles would change the maintenance recommendations.
To establish a trend of what’s going on inside the equipment, be consistent with the equipment used to pull a sample as well as the location from which the sample is taken. For instance, if you collected a sample with a clean (100 particles) bottle, the next sample should be obtained with the same type of bottle.
While it’s important to collect oil samples in a clean container, utilizing superclean and ultraclean containers may increase your expenses without seeing much gain. The average maintenance program will receive the most benefit from using ISO clean bottles if particulate and cleanliness testing are being conducted.
Remember, the hardware employed to extract an oil sample should not disturb the sample quality but should be clean, easy to use, rugged and cost-effective. With the correct bottle type and cleanliness level, you can help ensure a representative sample is achieved.