Lubricating Oil Sampling Procedures
To properly evaluate machine conditions, the oil samples submitted for analysis must be representative of the system from which they are taken. For best results, follow these guidelines:
1. The machine being sampled should be brought to normal operating temperature. Oil should be recirculated, if appropriate. This will ensure that insoluable and semisoluable contaminants are uniformly dispersed throughout the system. Samples taken from machines that have been inactive for long periods are not representative.
2. Oil samples should always be taken in the same manner and from the same sampling point.
3. Do not sample a machine immediately after an oil change or after a large amount of make-up oil has been added.
4. Use a clean dry container to draw the oil sample. Ship samples in the plastic bottles provided in the package. Hydraulic fluids or other oils submitted for a particle count analysis should be submitted in the "super clean" bottles provided when special testing is requested.
Sample Gun Method
The oil test package includes a plastic sampling bottle used for collecting and shipping samples. A special inexpensive sampling gun is also offered as an option, together with convenient lengths of plastic sampling tubing. The plastic sampling bottle fits directly into the sampling gun, and the oil sample can be drawn directly from the machine into the sampling bottle. The sampling gun allows the user to draw representative samples quickly and with a minimum of effort.
Procedures are as follows:
1. Measure a sufficient length of plastic sampling tubing to reach from the sampling gun through the sample aperture and into the machine sump or reservoir. If the machine has a dipstick, the tubing should be measured against the dipstick to establish the proper sampling depth.
2. Loosen the nut on the sample gun head, insert the free end of the sampling tubing through the nut (about 1/2 inch past nut) and tighten the nut to compress the sealing ring to obtain a vacuum-tight seal. Screw a clean plastic sampling bottle into the gun adaptor.
3. Holding the sampling gun upright, draw oil into the bottle using the piston lever until oil is within 1/2 inch of the top. To stop the oil flow, break the vacuum by partially unscrewing the bottle. Remove the bottle from the adaptor, screw the cap on tightly and wipe the bottle clean. Fill out the unit or machine identification number on the bottle label.
4. Replace the plastic tubing after each sampling to avoid sample cross-contamination.
Sample Valve/Petcock Method
Care should be taken to install the valve on the lube system in a location that will ensure representative oil samples can be drawn. The exterior of the valve should be wiped clean prior to sampling to ensure that no external contamination finds its way into the oil. Stagnant oil should be drained from the valve by drawing a small oil sample into a waste oil container just prior to collecting the oil sample in the plastic sampling bottle. Screw the bottle cap on tightly and wipe the bottle clean. Fill out the unit or machine identification number on the bottle label.
Oil Drain Method
Clean the area around the drain plug thoroughly to avoid sample contamination. Allow some of the oil to drain into a waste oil container prior to collecting the oil sample. Place a clean dry sample bottle into the oil stream and fill it to within 1/2 inch of the top. Screw the cap on tightly and wipe the bottle clean. Fill out the unit or machine identification number on the label.
NOTE: When taking oil samples from hydraulic systems for particle count analysis, special care must be taken to assure the samples are representative and that they are contamination free. Use the special "super clean" bottles to sample oils for particle count analysis.
