What impact does long-term use of the centrifugal pump casing have on the pump’s operation?
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As the title suggests, what impact does prolonged use of the centrifugal pump casing have on the pump’s operating parameters? For example, if there is a leak in a particular area of the pump casing, will repairing this leak by welding or other methods have an impact on the pump’s operation?
If the mouth ring is mounted on the pump casing, over time it will wear against the impeller, resulting in an excessive gap that affects parameters such as flow rate
What about other areas other than the mouth ring?
Whether or not there is a mouth ring, it will wear out over time, leading to a decline in performance. If there is a lip seal on the pump body, it can be replaced simply by swapping out the lip seal. If there is no mouth ring on the pump body, it is best to replace the pump body or fabricate an impeller that matches its dimensions. If other areas are corroded and leak, patch welding is allowed; just grind them smooth.
I believe that over time, as long as the pump casing is not severely deformed or corroded, it will not affect the pump’s performance. As for welding repairs, the casing can certainly be welded back together, but certain internal components of the pump, such as the impeller and shaft seals, cannot be repaired by welding in theory.
Personal opinion: Over time, the pump casing of a centrifugal pump may experience corrosion and wear in the smaller flow channels, but this does not have a significant impact on the pump’s performance. If perforations occur, they can be repaired by welding. However, there are two areas of wear that have a significant impact on the pump’s performance parameters: one is the wear of the sealing ring (seal ring); of course, this factor is taken into account during pump design, and it can be replaced during major repairs ； The other is the \"separation lip\" of the pump body, which is the point closest to the inner cavity of the pump body and the outer edge of the impeller. Here, an increase in the gap again affects both the flow rate and head of the pump.
To be precise: all defects in metal pump bodies can be repaired; the key is to select the appropriate welding materials based on the base material and to develop reasonable welding and heat treatment procedures. Additionally: The factor that has the greatest impact on performance is the wear at the mouth ring area. If the design does not include a mouth ring and wear is severe, it is possible to consider installing one, fixing it with spot welding, and replacing it periodically. (I worked in 1988 for a company, where I was responsible for fitting the pump casings and ring gears for three residue oil pumps; those pump casings and impellers were not replaced until the year 2000.) The subsequent situation is unknown)
Areas other than the mouth ring can be rewelded, but could issues such as ion corrosion occur?