Sump Design 1

[arm83]

Hi all,

With reference to my previous post thread407-176454 (Cooling towers and vertical pumps), I am designing a sump for the vertical wet pit pumps. I have thus far used the Hydraulic Institute guidelines but was wondering how to determine the depth of the sump. Keeping in mind that the speed of the water coming in has to be 1m/s max (at least according to HI).

The figures I am working with are basically the capacity of the pump and the dimensions from HI.

Any help or guidance would be greatly appreciated.

 

[dtn6770]

thread378-173908 has some good discussion on the submect.

 

[Artisi]

Normally sump depth is a function of the height of the pump inlet above the sump floor plus the submergence required to eliminate vortexing from the surface at the minimum operating level of the sump.
If NPSHr / NPSHa is marginal you will have to increase the submergence to provide adequate NPSHa at the minimum operating level of the sump.

If this is a major pump installation with pumps of high flow rates I would be seeking professional. Believe me,a hit and miss approach is a recipe for disaster and I am sure there are many in this forum who can tell you some horror stories on poor intake design and vertical pumps.

 

[ccfowler]

arm83,

Artisi has just given you the best possible advice that I heartily second. You need to get competent professionals involved in the analysis and resolution of your problem(s).

Considering the information that you have provided in these two threads, you appear to be in the disquieting situation of having limited experience in these matters while having to attempt to implement a "solution in search of a problem" and having to do this on a shoestring budget. Having knowledge of such situations in the past, the prospects of a happy outcome for your project do not seem very promising. I sincerely do wish you very good luck.

 

[rmw]

Since you are going to have to make a pump selection, ask the pump vendors from whom you are seeking bids to make a recommendation. They might have differing requirements and it would be terrible to design the sump only to find that it didn't fit the pump you selected. While they all work to the same Hydraulic Institute standards, they have areas where they have specific requirements based on their experience with their products.

rmw

 

[arm83]

Thank you everyone for your valuable input. I will definetly consult the manufacturers.