Pump Casing Cover Erosion

[icarusK]

Dear all,

I would like to find the cause of the pump casing cover erode as below picture.

Casing cover & impeller have the same material i.e A 351 Gr. CF8 but casing cover material are eroded, having pin hole & their is no erosion effect on impeller side.

Please let me know the cause.

 

[Artisi]

Erosion, probably from recirculation of solids in the pumped material, what are you pumping?

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.)

 

[icarusK]

Pumping fluid is clarified warm water in Steel Plant.

 

[JJPellin]

The damage occurred in that location because of the flow path. Heavy solids that get into that area are trapped. Centrifugal force is spinning them to the outside. The balance holes are close to the shaft. The flow path crossing the backside wear rings is from the OD toward the ID and axially away from the impeller and toward the head (cover). This does not fully explain why the backside of the impeller is untouched. But, I have seen this before. There may be some difference in surface hardness as a result of different processing of pressure boundary parts versus internal parts. But, in any case, the problem is abrasive solids.

We have installed swirl breaks in this area and added hard coatings to resist this problem.

Johnny Pellin

 

[Artisi]

I would suggest that the back side of the impeller is relative free from erosion as the solids are being rotated by the impeller at impeller rotation speed, therefore no impingement on the impeller.


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.)

 

[gempump]

If there is a decrease of Flow Rate and Head ?Running properly without Vibration and Noise? How about the other pumps ? I think you have the right to claim .

Heavy-Duty Centrifugal Slurry Pump Manufacturer

http://www.gempump.com

 

[Artisi]

gempump: would you like to expand on "the right to claim" - claim what?

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.)

 

[gempump]

Artisi:Claim money or a new casing.Some doubt the quality of China’s equipment.

Heavy-Duty Centrifugal Slurry Pump Manufacturer

http://www.gempump.com

 

[Artisi]

gempump: Did you actually read what was the likely cause of the erosion, which has nothing to do with material quality.And why assume this is a Chinese made pump, which by the way has nothing to do with the problem.

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.)

 

[georgeverghese]

Is this pump in cooling water return service from the continous casting section of a steel plant ? - if so, this return water would be full of erosive debris from this plant. May be the operators must have gotten tired of cleaning up the pump suction strainer, and pulled out the strainer element ?

 

[Artisi]

OP.-- any idea what the pH is of the pumped liquor?

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.)