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High flow with Low head pump

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DDBR

Civil/Environmental
Feb 19, 2016
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I have to pump a large volume of water out of a pond quickly during a storm event to prevent flooding. The pond cannot be enlarged so I am going to install a pump with a high flow rate with low head conditions. The target discharge rate is 1500 gpm with a static head + friction head of less than 15 feet. Does anyone know of a pump that will meet these requirements?
 
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Google axial flow, and mixed flow pumps; these are what you want. These pumps are perfect for throwing water over a levee wall (the kind that Louisiana would never pay for and could have prevented Katrina flooding...but thats another story).

Axial flows typically between 5-40 ft of head, mixed flow between 30- 80' or thereabouts. As said above, they are typically vertical pumps; axials (sometimes called propeller pumps)are named such because axial forces are dominant in moving the fluid axially along the shaft. Their energy is used to create flow, not head. Specific speeds usually range from....maybe 10K-25K....

1500 gpm is really not a huge volume; some of these monsters can easily move 100,000 gpm. Go check out Goulds, Floway, Flowserve, Patterson, Sulzer (they now own the old Johnston pump line). A cheaper version was made by a company called Low-Lift. They were totally fabbed pumps, no castings, and had huge installation base. Don't know if they are still around.
 
Just be aware that axial flow pumps have a different pump cure to centrifugal pumps and can generate much higher head a low / no flow and also use a lot more power at low / no flow.

So just use an open pipe with no valves on the outlet. typical axial pump curve below

axial_pump_mkfx82.jpg




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That's a pretty big rock. It will pass it, but you'll probably break / bend the pump in the process.

You either need to screen this out or use a trash pump.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
I would like to use a trash pump but I do not think a trash pump will meet the discharge rate and the static head requirements.

1500 gpm @ 10ft head
 
Then use screens or sumps within the pond and discuss what you're pumping with the pump vendors. Giving the technical sales team is worth 100 e-mails or data sheets.

What you're doing isn't unusual so they will have types of pumps which are suitable for dirty water with some level of dirt / entrainment, but 50mm is a bit big.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
Even trash pumps have their limitations, you need a screen ahead of the intake to ensure trouble free operation.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
 
You may need to look up the Hydraulic Institute Standards for configuration guidelines for the inlet sump /settling chamber compartments and other details in the inground civil structure for these pumps.
 
lilliput1 - Ground water limits the depth of the pond.

georgeverghese - The plan is to place these pumps in a inlet sump. However, there is always a chance of some type of solid making its way to the pump and cause clogging.
 
The HI standards cover many design details for this civil structure that you may be guessing or think "should be alright " otherwise. One or two critical parameters are (a) the gap between the "grade " in this inlet sump and the bellmouth of the pump (b) the distance between the end of the diverging cone in the feedline and the vertical centre line of the pump (c) gap between multiple pumps sitting in the same sump.
 
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