Water Pumps Question

You are pumping at a rate of 78.3 gpm.

Get a bigger pump, shorten the pipe length, or wait longer. It will take 80 hours to fill the tank at this rate.

What sort of altitude are we looking at on the syphon side and what is the static head on the discharge side and is this pump rated for the load?

The pump is rated at 200 GPM, we pumping from a tank about 800 feet away from the pump and moving the water 38 feet high. Do you think it would help us to move the discharge to the bottom of the tank. This has been topic of discussion here on the job. Some think that it is better to pump it in the top because there is less volume pushing down on the water enterance and some think that there is less head pressure if you pump in the bottom. Thanks for your thoughts.

Sorry - clicked the wrong button.

" because there is less volume pushing down " - The size and the volume do not have an effect only the height.

If it did one can create a "pump" with a big down and a small up pipe.

The friction losses far exceed the 38 foot static head requirement.

A three-inch pipe flowing 80 gpm loses 31 feet per hundred feet (31 x 8 = 248 feet).

Initially (tank empty) you stand to gain some pumping to the bottom of the tank, but as the tank fills, you now have to overcome the static head of 40 foot tank pushing back against the pump discharge.

But again, the friction head loss is the problem as it far exceeds the lift requirement.

Since friction head is a function of pipe velocity squared, you really can't get around this problem with such a small diameter pipe.

I'm more curious about where you're getting it out of the supply tank.

Are there provisions for vacuum relief of the supply tank?

How about pressure relief on the receiving tank?

Just my $0.02

The static head is 16 feet, yes there is a vacuum relief on both tanks, we can't shorten the distance between the 2 tanks and fire hose is all we have to pump through. Thanks for all your help.

By the way, welcome to CR4!

Your pump may be rated 200 gpm at say 60 feet of head, but because of frictional loss (pressure drop ) in the hose, you are most likely pumping against a much greater head (total dynamic head) than you might have realized; say 120 feet of head. As a practical matter, 150 gpm is about as much as you can run through a 2.5" hose. That would take about a 15-hp pump, maybe getting by with 10.

That was very off-the-cuff, but I think your experience confirms it. Your tank is ~376,000 gallons. At 150 gpm, that's 2500 minutes!