Centrifugal pump impeller damaged
Thread Content
There is an existing horizontal centrifugal pump, model ZXF40-25-315, with a flow rate of 6m3/h, a lift of 30m, and a rotation speed of 1450r/min. During operation, there was no flow, and the inspection found that the impeller was broken. What could cause this situation? How should this be avoided in the future? (impeller material: titanium)
Is it an impeller quality problem? Or is it an installation problem?
Is the fracture a fatigue fracture? Or is it broken due to stuck points?
Judging from the wear film on the impeller end face, it should be a material problem. There may be things like chemical fibers embedded in the gaps, or impurities in the material that are not easily broken may be embedded in them, and act together with impurities with greater hardness. Guess, I don’t know what type of material the medium of this pump is. For reference.
The medium does not contain concentrated salt water, and the volute and impeller have previously accumulated material. However, during the disassembly of the machine, no debris was found in the volute.
Oh oh, that's right. It may be due to temperature changes that crystallization accumulates in a certain corner of the pump. When it is started, the impeller will be scratched at a certain position and the stress surface will be uneven (deflection). This result can be achieved in a few cycles. Therefore, before starting the pump, crank it to see if there is any scratching, caching, or whether it needs to be rinsed with clean water. Can a corresponding settling or separation device be set up before entering the pump? For example, set up a centrifugal sedimentation tank with tangential entry. For reference.
Judging from the breakage, it seems to be a welding problem. Generally, this kind of impeller is forged as a whole.
It broke, and the welding seam was a little thinner.
I don't know much about whether the medium will cause intergranular corrosion or electrochemical corrosion. The wear of barter is relatively serious. If welding, it needs to be done well. After all, it is a tangential force and it is not easy to weld. The overall casting will be much better.