Pump Impeller

[Giray Veli]

Hi everyone, we are using this pump to transfer sulphuric acid. Our concentration is %85 and this impeller MOC is PVDF. This impeller got some damage but we don’t know the reason. There is no particule on fluid it is clean and closed system. I have faced this problem 3 times and I want to know reason to solve problem. I have calculated the NPSHa and it is almost 6m, NPSHr is 3m hence there is no cavitation. What can be the reason could u help me?

 

[Artisi]

Have the previous failure looked to be similar?
A few more photos at better quality of the failure site, the impeller hub and along the periphery of the impeller.
There are areas that look like damage but unclear in the current photo.

 

[Giray Veli]

Have the previous failure looked to be similar?
A few more photos at better quality of the failure site, the impeller hub and along the periphery of the impeller.
There are areas that look like damage but unclear in the current photo.

We have 2 pump and one of standby, both pump’s impellers got damaged and this is the standby pumps impeller photos and the cracks part is same but, the body of impeller has wave shape I don’t know why. I think can not be appropriate for fluid but the vendor said it is manufactured for sulphuric acid.

 

[MintJulep]

Have you considered that the material might not be PVDF.

A different material provided by mistake.

Counterfeit material.

 

[Giray Veli]

Have you considered that the material might not be PVDF.

A different material provided by mistake.

Counterfeit material.

I have used 3 different pump in here and all pump’s impeller got the damaged. We have bought all pumps a reliable vendor.

 

[Artisi]

Temperature problem?

 

[pierreick]

Hi,
Consider the resources attached to support your work.
Who are the reputable suppliers? Can you share their names and proposals for your application?
From the documents shared you will see that "PVDF" is not the recommended material, prone to rupture, lack of mechanical strength.
Alloy 20 or Steel coated Teflon could be a better option.

BTW, no indication about the temperature.

Pierre

 

[goutam_freelance]

he body of impeller has wave shape I don’t know why

It could be due to fatigue failure arising from fluid dynamic forces. Please check the type of crack.

It is better to have an impeller with a smooth streamline flow.