Eccentric casing in high energy pump

[sinectica]

Hello guys,

I would like to know if someone has experienced hydraulic problems in Sundyne pumps related to its eccentric casing (Z series).
Does anybody studied the hydraulic problems (recirculations) and consequent erosion that could arise when having an eccentric casing (volute) in a high energy pump as Sundyne Z series?

Thanks for your support,
sinectica

 

[JJPellin]

You may need to be more specific. What problems have you experienced that you feel might be related to the Sundyne case design? What aspect of the design concerns you? You mention the eccentric casing. It is not clear to me what you are referring to. Our facility has about 175 Sundyne pumps. We have experienced many "hydraulic problems" with these pumps. I am not sure what you mean by "recirculations." Are there any specific locations where you feel erosion damage could be caused by this problem? If you give us more details, you may get the answers that you are looking for. But, with the lack of details in your original post, you are probably not going to get anything of value.

Johnny Pellin

 

[sinectica]

Thank you for your reply JJPellin, maybe I was not clear with my question. I would like to know basically the following: is an eccentric casing with cutwater mounted in a Barske pump (like Sundyne) more sensitive to experience internal flow recirculations than with concentric casings?

As far as I know this pumps use to mount concentric casings and I don't know in which operating conditions is better to install eccentric casings. I am experiencing erosion problems with a very particular pattern on the casing that would suggest secondary flows. Casually this pump has eccentric casing and I would like to know what problems could appear in this kind of pumps when an eccentric casings is installed.

Thank you in advance

 

[Softedge]

sinectica,

in order for a centrifugal pump to operate without recirculation it must be eccentric. if you are referring to an involute pump it will also be eccentric. if you are having problems at the cutwater that are a result of wear, not corrosion or pitting, then you most likely have a pump selection problem. the pump may be operating too far left of the b.e.p. i would look at the system and pump to determine if it is the right pump for the application.

arthur

 

[JJPellin]

I still don't understand. Which models of pump are you concerned about? What damage have you seen that you believe could be related to an eccentric casing?

Sundyne pumps often experience cavitation damage in unusual locations. We have seen cavitation damage through the balance holes of the impeller and in a ring around the hub on the backside of the impeller. Our newest Sundyne pumps have experienced cavitation damage in the bottom of the diffuser just at the corner where it transitions into the inducer throat. We have seen a number of high speed pumps that had deep cavitation damage in the diffuser throat from operating at excessively high flow. Are any of these examples comparable to what you are seeing?


Johnny Pellin