Grease sampling set
Figure 8: Grease sampling set
Grease samples are taken in parallel with, i.e. at the same time as, the inspection measurements. The analysis of the used grease provides additional information about the raceway condition.
Bearings with grease sampling ports
The grease sampling set comprises a plastic tube, various cap plugs, a suction device, a sample box for up to 5 grease samples, and an information sheet. The procedure is described in detail.
Take the grease samples from the main loading zone.
Remove the screw plug (M16 EN ISO 4762) selected for taking the sample: item 1 and if necessary item 2 opposite (figures 9 and 10).
Figure 9: Three-row roller bearing slewing ring with grease sampling ports
Figure 10: Single-row ball bearing with grease sampling port
Before taking the grease sample, cut the supplied tube at an angle of 45° so that it is slightly longer than the grease sampling port. Then insert the tube into the raceway area of the port (figure 11).
Figure 11: Taking a sample
Make sure that the surface cut at 45° faces in the opposite direction to the direction of rotation (figure 12).
Figure 12: Detail of the sampling
The sampling ports must be closed again with the screw plugs.
When the sample has been taken, close both tube ends with the plastic caps.
Number the grease sample and place it in the labeled sample box.
Add the necessary information (see the grease sampling set in figure 8) to the top of the sample box.
Bearings without grease sampling ports
If there are no grease sampling ports provided on the bearing, one or more grease samples are taken at the seal. This area near a grease nipple must be cleaned. The sample should be taken preferably in the main working area and/or offset 180° to it.
During regreasing at the prepared grease nipple (without rotation of the bearing), the first grease escaping from the sealing lip is taken as the sample (figure 13). 3 ccm are enough.
Figure 13: Taking a sample of grease from the sealing lip
Note: Be careful when taking the sample or the result may be falsified by contamination.
Fe limit values
A limit value for Fe contamination in the lubricant depends greatly on the operating parameters and the lubrication intervals. Depending on the application, the value can be as high as 20,000 ppm.
Wear curves
The diagrams show the increase in wear and the increases in Fe particles and the PQ index as a function of the operating hours (figure 14).
Figure 14: Wear curves
For standard applications see the values in tables 1 - 3. When the limit values are reached, please contact Rothe Erde.
Table 4: Measurement table (click to enlarge)
The measurement values, analysis values and bearing-specific information should be entered in a separate table (see table 4) and forwarded to Rothe Erde.
Rothe Erde GmbH
Service
Beckumer Straße 87
59555 Lippstadt
Germany
service.rotheerde@thyssenkrupp.com
Rothe Erde sends the grease samples to an approved, qualified laboratory.
Advantage: Short processing time and notification by e-mail about the analysis results and wear measurement.
For the grease sampling set please contact the following address:
Rothe Erde GmbH
Tremoniastraße 5–11
44137 Dortmund
Germany
Telephone +49 (2 31) 186-0
Telefax +49 (2 31) 186-2500
sales.rotheerde@thyssenkrupp.com