Oil analysis
How to pull an oil sample: step by step
A repeatable procedure for drop-tube and valve sampling, with the common mistakes to avoid.
Who and when
The person who takes the sample matters as much as the person who reads the result. Train them, give them a written route and keep the pattern identical. Sample while the machine is running at normal operating temperature.
Drop tube or pump method
- Cut a new length of tubing, always to the same recorded length for each machine.
- Fit it to the sampling pump so it protrudes about 12 mm below.
- Place the tip at the middle of the oil depth and at least 50 mm from the bottom, sides, oil surface and moving parts.
- Flush three times the volume of the tube into a waste bottle before collecting.
- Pull the pump handle one to three times and fill the bottle only to three quarters.
- Release the vacuum, cap the bottle immediately, discard the tube, wipe the pump.
Valve or pressurised method
- Flush the valve and tubing with three times the path volume into a waste bottle.
- Use a vented bottle cap or a vacuum pump so the bottle can vent.
- Fill to three quarters with the bottle removed mid-stream, then cap.
- Close the valve and refit the dust cap.
Good habits
Tell production you are in the area, wear gloves and the right protective clothing, keep sampling points capped until use, label the bottle immediately with date, machine, oil type and run hours, wipe the bottle and ship it in a sturdy mailer.
Frequent mistakes
Reusing tubing, sampling from the bottom drain, filling from a stagnant dead leg, taking samples from a cold machine and changing the length or flush time between sample rounds.
Takeaway. A repeatable method beats a sophisticated one. Same tube length, same flush, same point, every time.
Put it to work in the tool