Seawater Intake

[jmas]

Does anybody knows why the designer of this intake, decided to have a above-ground discharge for seawater pumps, first, and then let them going U/G after some meters?
Let consider it in another way. If the outlet run U/G from the begining, then we have shorter pump, and therefore less material for it (cheaper pumps).
FYI i download the picture by googling.

 

[cvg]

this is a typical installation and makes it much easier for maintenance of the pumps, motors, valves and gauges on the discharge line. Also keeps the motors up higher which helps to protect them from flooding. May also reduce the depth of the pump cans. Size of the pumps would not change. Assuming you do not want your electric motor below ground in a vault but prefer it above ground, then the drive shaft would be much longer and that would result in a more expensive pump.

 

[jmas]

Thank you cvg for your reply.
Let see it from this point of view.if take a look to the picture again it seems the piping is not CS. it resembles more to the HDPE (or GRP), which is weak in shear comparing to the CS. in this regard i think settlement of concrete intake is main reason to have A/G discharge to avoide direct shear in piping, and change it to tension and comopression at some meters away.Am i right?

 

[cvg]

I serously doubt this is HDPE. If I had to guess, I would say this is either steel or ductile, but probably steel. I would never recommend HDPE pipe in an above ground pump discharge header and for multiple reasons not counting shear or bending strength of the pipes. I have not used GRP for pressure applications so cannot comment on the suitability of that particular type of pipe in this application. I would hope that the design accounted for settlement.