After the impeller of the DF multi-stage pump becomes clogged with scale
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After the impeller of the DF multi-stage pump became clogged with scale, acid cleaning was performed on the pump; yet the current consumption during operation was extremely high, and it remained high even when the outlet was not opened. The pump rotated smoothly when turned by hand – what could be the reason?
Conduct a disassembly inspection to check whether the balance tube is blocked; there may be friction within the internal components, resulting in high resistance and poor axial force balance. The shaft runout is large, causing excessive friction in the axial force balancing device.
I’ve never heard of using acid cleaning to deal with blockages in pump structures; for pumps made of materials that aren’t resistant to acid, acid cleaning can cause severe corrosion. Usually, the pump is disassembled and each component is cleaned individually. You need to disassemble the pump now to check whether each component has suffered severe corrosion due to acid washing, or if scale has not been removed properly. If the pump is fine, then the pipelines need to be checked (such as filters, valves, and other components)
This is the first time I’ve heard of directly acid-washing centrifugal pumps: Does the poster on Floor L not worry that the acid washing will damage the pump? And then what about the extra costs involved in disassembling it for repair? Just like now? Take it apart; P
It’s possible that the impurities inside the pump weren’t removed, causing jamming. . Dismantle the pump for inspection
The current remains extremely high even when the outlet valve is not opened; this is likely due to rubbing between the moving and stationary parts of the water pump after it is started following the acid cleaning process. The fact that there is no jamming when the pump is turned manually before starting does not guarantee that no rubbing will occur after it actually starts operating. This is because, after the pump starts, an axial thrust acts on the rotor, and the balance disc together with the thrust bearings help to maintain the pump’s axial position. It is necessary to check the shaft play of the water pump, including both the total shaft play and the partial shaft play. When the balance disc is removed (and its position is replaced by a dummy shaft), the measured shaft play represents the total shaft play, while the shaft play measured after the balance disc is reinstalled corresponds to the partial shaft play. Generally, the partial shaft play is half of the total shaft play. If these values do not meet the required standards, the pump should be disassembled for inspection. Closed acid cleaning of the feed water pump is not recommended; it is better to disassemble it for cleaning.