Cavitation Resistant Coating for Pumps
Cavitation Resistant Coating for Pumps
(OP)
Hey guys!
We have this problem on our plant. Severe cavitation damage are incurred in our pumps and we are currently studying the cause of it. For the mean time we are in the process of repairing the pump since operation of the pump is critical in the process.
We are looking into cavitation/erosion resistant lining to be applied as mitigation to prevent further damage to the pump internal components while we are finding an effective solution to eliminate the cause. I would like to consult if this method will be effective in preventing or at least minimizing the damage caused by cavitation.
Are there other considerations that i should be looking at? The pump is water service with 316SS impeller and CS volute.
Regards,
CR Radovan
We have this problem on our plant. Severe cavitation damage are incurred in our pumps and we are currently studying the cause of it. For the mean time we are in the process of repairing the pump since operation of the pump is critical in the process.
We are looking into cavitation/erosion resistant lining to be applied as mitigation to prevent further damage to the pump internal components while we are finding an effective solution to eliminate the cause. I would like to consult if this method will be effective in preventing or at least minimizing the damage caused by cavitation.
Are there other considerations that i should be looking at? The pump is water service with 316SS impeller and CS volute.
Regards,
CR Radovan





RE: Cavitation Resistant Coating for Pumps
I don't think that your part would support a harder overlay.
And this is just temporary.
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P.E. Metallurgy, Plymouth Tube
RE: Cavitation Resistant Coating for Pumps
http://www.belzona.com/en/products/2000/2141.aspx
I haven't used it, and thus I can't vouch for it. The coating manufacturer will have to convince you of its performance and efficacy.
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Cavitation Resistant Coating for Pumps
May I know why elastomer or polymer coating?
Most of the articles I have read suggested to upgrade to a harder material or conduct surface hardening. However, what do you mean by "our part cannot support a harder overlay"?
I apologize for the questions but i am eager to know why.
regards,
CR Radovan
RE: Cavitation Resistant Coating for Pumps
Yes, I am actually looking into that product by Belzona as it is also one of the product stating it follows ASTM G32-92 testing. But there is the "modified" word in the description for that.
However, my question is - are linings be enough to prevent damage to the newly repaired pumps?
Regards,
CR Radovan
RE: Cavitation Resistant Coating for Pumps
If you hard coat then the substrate needs to be strong enough to assure that you don't flex (and fail) the coating.
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P.E. Metallurgy, Plymouth Tube
RE: Cavitation Resistant Coating for Pumps
.....changing to a more corrosion resistant and/or higher hardness material may not improve cavitation resistance. Excessively hard
materials may not be suitable if they lack the toughness required to withstand the high local pressures and impact (shear loads) of the collapsing bubbles.
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Cavitation Resistant Coating for Pumps
RE: Cavitation Resistant Coating for Pumps
RE: Cavitation Resistant Coating for Pumps
We are on it. But process needs the pump to be operating and can only give a short period of time. So for the mean time we are to operate it with a mitigation to minimize the damage.
Thank you and regards,
CR Radovan
RE: Cavitation Resistant Coating for Pumps
I never thought of it that way. Thank you for the additional information. We'll look on to these materials and methods of application.
regards,
CR Radovan
RE: Cavitation Resistant Coating for Pumps
Again, thank you for the reference and information.
Regards,
CR Radovan
RE: Cavitation Resistant Coating for Pumps
Thank you for the information. I believe we have Enecon here locally.
As you said application is one factor to consider, I have read studies with results of the coat chipping off concluding that there was a fault in the adhesion. I guess the company will be the one to guarantee this. We'll also look onto the application methods you mentioned. Thank you for this.
Regards,
CR Radovan
RE: Cavitation Resistant Coating for Pumps
I agree with bimr in the first instance, mitigation of cavitation should first be examined through change in process conditions which have resulted in the cavitation. However, in the event that this is not possible or that the spectrum across which cavitation is occurring is too broad to design out then use of polymeric coatings such as the Belzona 2141 is the next option. As EdStainless correctly pointed out, these materials resist cavitation by absorbing the implosion forces of the vapour bubbles. Cavitation causes damage by impacting the substrate with a high velocity force. If this force exceeds the elastic limit of the material then damage occurs in the form of small pits. Use of harder materials therefore will not solve this problem. Belzona 2141 has a high elastic limit allowing it to absorb the high velocity forces.
In response to the question of the 'modified' version of ASTM G32-92. The modification was to coat the sample instead of the vibrating probe. It was found that coating the probe with the elastomers resulted in heat build up in the elastomers and a measurement of the heating of elastomers through vibration instead of actual cavitation resistance. By coating a sample under the probe, cavitation was induced and the Belzona 2141 tested for 'true' cavitation resistance.
- Kyle
RE: Cavitation Resistant Coating for Pumps
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P.E. Metallurgy, Plymouth Tube