Case Study 4
Analysis Results of Final Drives In Dump Truck After Filtering with Lubemaster OS600.

Results achieved by a coal mining operation using a Lubemaster OS600 to filter oil taken from the final drives of a dump truck.

All samples have been prepared by exactly the same process using the industry standard 3μm Millipore method, with photo’s processed at X200 magnification. Calibration on this print in actual size, 1 ml equals 1μm.

The first slide is a photo of the filtergram very shortly after the commencement of filtration and is showing the dark colour typical of the unfiltered oil taken from the final drives, with a high number of large particles to 30μm visible. The contamination visible consists of dust and seal material as the dark particles, and the white as the silver metal particles. Note the overall colour of the sample with the background quite dark, which is due to the presence of particle contamination.

After filtering the oil for 12 hours, a microscopic examination was undertaken which demonstrated that the cleanliness level was well below the cleanliness levels as stipulated by GE for re use in their drives; that is ISO 4406 at 18/13 with particles less than 10 μm not of interest

Figure 1. Used oil in the early stages of filtration, showing wear particle and dirt contamination at high levels.

Figure 2. The same oil after 6 hours filtering.

Figure 3. The same oil after 12 hours filtering showing the reflected light mode. i.e. light shining onto the slide and being reflected off the top surface, showing the actual surface perspective.  Note that the dirt background has been almost completely removed except for 3 particles and that there is only one metal particle visible, which is less than 1um in size.

Figure 4. The same slide as figure 3 except that the microscope light is set on transmitted light, with the light shinning through from the bottom of the slide. This perspective highlights the absence of large particles, which will normally show up as black spots. The dark spots show all that remains of the solid particles, which are all less than 1um in size.

Figure 5. A filtergram of the sludge concentration, which has been removed from inside the centrifuge rotor, after running, magnified X200 taken from 0.01 of a gram of sludge.  Large particles were observed in numerous numbers ranging to 250 um in size.  Most of the large visible particles in this photo are around 50um in size, coming from a complete sludge covering inside the centrifuge rotor approximately 3mm in thickness.