Question 42 QMED05 - Machinist-Pump Technician

The Correct Answer is B **Why Option B ("Draining the bottom of the bearing lube oil sump.") is correct:** In a lubrication system where an oiling ring (or slinger ring) is used, the oil reservoir (the sump) is typically a quiescent area beneath the journal. Contaminants such as heavy wear particles, grit, and free water (moisture) are denser than the oil and, due to gravity, they settle to the absolute lowest point of the sump. To remove these settled contaminants, standard maintenance procedure requires periodically opening a drain valve located at the very bottom of the bearing sump. This process, often called "bottom draining" or "sump blowing," removes the accumulated sludge and moisture without replacing all the clean oil above it. **Why the other options are incorrect:** * **A) Rotating the handle of the lube oil strainer:** Rotating a strainer handle (a duplex strainer or basket strainer) is designed to dislodge large debris caught on the mesh so that it falls into the strainer housing's bottom bowl, or to switch flow to a parallel strainer element. While this helps clean the oil going to the bearing, it only targets debris large enough to be caught by the mesh and does not remove the contaminants (especially water and fine grit) already settled in the bearing's own local sump. * **C) Changing the filter element:** Filters are used in forced lubrication systems, not typically in simple self-contained oil ring bearings. Even if a small kidney-loop filter system were present, changing the element removes particles suspended in the oil, but it does not remove the heavy sediment and free water that have already settled out of circulation and collected at the bottom of the bearing housing/sump. * **D) Draining the bottom of the strainer housing:** Draining the bottom of a strainer housing removes the debris caught by the strainer element (as mentioned in A). However, it does not clean the *bearing sump itself*. The bearing sump is the location where the contaminants (grit, wear particles, and moisture) that were carried into the bearing settle out of the localized oil circulation loop.