Simple Pump Application Question/Suggestions?

[piffer]

I am trying to design a simple pumping system to transfer water over a 10' high wall that divides two basins. I want to use a 7.5HP submersible pump for this application. Design flow will be ~1-1.3 MGD. Static head will vary between 2 and 7 ft. In order to create sufficient TDH, I considered using 4" piping with a few bends, but the velocity in this size of pipe seems too high (>15'/sec). It would be nice not to have to use a valve to create additional head. Any ideas? Could an orifice plate be sized to limit flow (BEP for this pump is ~750 GPM @ 18 FT TDH)?

 

[Artisi]

First up look at reducing impeller diameter, this will reduce flow and head - flow varies in proportion to diameter - head at the square of diameter.

Why are you worried about velocity - using the pipe system to reduce head is not much different than using a valve or orifice plate.

Alternately select a pump more suited to the application.

 

[dabluffrat]

is it a multi stage submersible pump? de-stage it or slow down the speed.

 

[moltenmetal]

What's your problem precisley with greater than 15 ft/second? 15 ft/s is at the high end of an economic velocity for long piping lines where you're worried about frictional loss and electricity consumption for your pump motor, but it's not an erosion concern unless the "water" you're talking about is really a slurry.

 

[BigInch]

Depending on sediment load, 15 fps can be a problem, not to mention potential water hammer concerns which can easily become problematic over 10 fps.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[BigInch]

BTW 10 fps is the thumb for long pipelines.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/