Axial wear at the undriven end of the liquid ring vacuum pump
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There is a liquid ring vacuum pump in our company. After disassembly and inspection, it was found that the shaft on the non-driving side was worn. There is a bulge between the two areas on the shaft where bearings are installed, and those areas have worn down. We’re not sure what caused this – could it be excessive vibration? We would appreciate it if everyone could help explain this. The condition of the damage is shown in the attached diagram
The inner ring of the bearing has slipped out of place, the clearance between the components is too large, and uneven clearance on both sides of the vacuum pump results in higher efficiency on one side only.
Typically, the bearing at the drive end is responsible only for radial loading, while the bearing at the non-drive end not only handles radial loading but also serves the function of axial positioning; therefore, it is logical that the bearing under combined loading at the non-drive end is the first to fail. On your pump, the drive side is damaged – is the non-drive side okay? From what you’ve written, it seems there are two sets of bearings on the drive side, right? Is it axially positioned at the drive end? If the outer surface of the shaft is worn, it’s definitely because the inner ring has shifted. The reason for this shift could be thermal expansion or some other factor, which needs to be investigated.
Such pumps generally adjust the clearance positioning via the non-driving end