Running a Sundyne LMV-311 Pump in minimum flow

[Pejman Hatami]

Hello everybody,
If you remember, I opened a thread for using a Sundyne pump for the following application:

Fluid: Water, Flow: 10m3/hr, Suction Press: 18 barg, Discharge Press: 140 barg.

Most of the experts are on this belief that either such an application will not be feasible or Sundyne declines to provide us with such pump, personally I was on the same wavelength with you but I continued my calculation on its hydraulic as well as CFD modeling study with a given set of diffuser, impeller and a range of RPM relative to a LMV-311 @ 150 Kw drive.

Outlets-at least on the paper- show that this could work, but still there is a question in my mind:
What would be the potential disadvantages staying at minimum flow (regardless of low efficiency).

Kindly comment if you have such experience with minimum flow and maximum head.
Warmest Regards,
Pezhman.

 

[JJPellin]

I did not think that LMV-311's could be rated to a pressure that high. Our highest pressure Sundyne is an LMV-346 with an integral diffuser. They could not meet our discharge pressure requirement (1900 psi) with a removable diffuser. In any case, we have generally had poor reliability when running a high speed, high pressure Sundyne of this type at or near minimum flow. If I had an application of this type and was going to use a Sundyne LMV-311, I would insist on the installation of a minimum flow spill-back loop and control the pump to run at a minimum 85 percent of BEP flow.

Johnny Pellin

 

[Pejman Hatami]

Dear Johnny Pellin,

thanks for your comments,did they finally provide you with 1900 PSI?
Could you please present its performance curve( if possible)?

Best Regards,
Pezhman.

 

[JJPellin]

They were able to meet our pressure requirement by the use of an integral diffuser. I have attached the curve for these pumps.

Johnny Pellin

 

[Pejman Hatami]

Thank you so much indeed.

 

[georgeverghese]

Another option that would save motive power on the driver would be to use a pump at say 50m3/hr at this dp (some performance point that is less challenging for a multistage centrifugal and enables higher hydraulic eff) and operate it on start stop basis to feed a pressurised surge vessel on level control. Flow out of the surge vessel would be on flow control or some other parameter that represents consumer demand.