Vertical pump horizontal movement

[mjsamman]

While inspection of our vertical propeller axial flow pump, we observed that the impeller is moving when we push it. (Video attached)
Do we have to dismantle the pump completely to check the sleeve bearing for any abnormal gap or there is another test we can do it.
The shaft hight is about 10m.

Thanks

 

[Artisi]

Dismantle.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Strong]

Looks like a lot of scoring or rubbing contact on volute surface. If it is very easy to move by hand and the with surface rubbing, then it looks like it is heading to the shop.

Walt

 

[goutam_freelance]

There could be worn out vertical shaft sleeve bearings.

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[TugboatEng]

What you are doing in the video is the test. With rubber bearings and such, it's difficult to gauge with micrometers due to the uneven wear surface. This type of test is the most reliable indicator of bearing wear.

 

[Nutzman]

What is the shaft material? 316 St.St? If so, that may be your problem? 316 is not a good "torque transmitter". It tends to "twist" like a progressive cavity pump shaft. The "bent" shaft wears the marine bushes, allowing radial wear on the wear rings/impeller/casing contact. Went through a court case to prove the point.

 

[mjsamman]

thank you all for your interaction
I have attached a sectional drawing for this pump.
The shaft material is Duplex stainless steel and pumping medium is sea water.
Note: the pump was overhauled since two years so it is impossible for the sleeve rubber bearing got damaged unless abnormal operation occurred.
As you know, removing and dismantling the pump is costly and time taking process.

 

[Artisi]

The drawing I see is completely useless, not that it really matters, you simply have excessive clearance in the lower bearing/s - if you want it fixed, dismantle the pump and carry-out the necessary repairs.
Yes its costly and time consuming so get it right this time and investigate why only 2 years operation from last repair.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[mjsamman]

Thank you Artisi for your valuable recommendation. We will go for it.
Regards

 

[accapumps]

More than likely, a bearing wear. I have to agree with the other ones.

 

[accapumps]

Also, check for shaft integrity all the way.

Nelson
ACCA Pumps
www.accapumps.com