Piping size versus total output
Piping size versus total output
(OP)
Is there a simple way to calculate how much water a pipe will transfer at given PSI's? Nothing too accurate for right now, just trying to get an idea how big a pipe roughly should be to get costs. In detail, how much water in gpm, will go threw a one inch pipe at 30, 60 and so on in psi. All pretty much flat, with the pump not selected yet. Any help would be appreciated.
Alex
Alex





RE: Piping size versus total output
RE: Piping size versus total output
http://www.efunda.com/formulae/fluids/calc_pipe_friction.cfm
See the hint to calculate a flowrate below the inputs, or find a website that has a calculator that has output pressure as an input, or just use the equations to plug and chug.
Good luck,
Steve
RE: Piping size versus total output
Generally discharge lines to pumps are designed with 6-8 ft per sec velocity for long distance transfer of water. Your inlet pressure is therefore no consideration in the flow quantity calculations unless you have a defined pressure drop in the piping system.
Narendra K. Roy
Gramya Research Analysis Institute,
PO box 4016, Vadodara 390015, India
Website: www.gramya.com ; www.charismaglobal.com
RE: Piping size versus total output
So now I am ready to stick in a sprinkler system and I am doing the research. My current pump is a half horse centrifugal by Fairbanks Morse. It puts out a little above 5 GPMs at the faucet with only about 30 psi. So I just wanted to know what would be the max size of pump for that line of one inch. Since the house pressure is fine, but I just need more capacity on the sprinkler side.
This is my plan to date, anyone with advice, feel free to tell me otherwise. I plan on removing the half horse and replace it with a bigger motor and a jet pump to match. I was then going to split the discharge immediatly before the pressure tank. One going to the house with a regulator and the other going to the sprinkler main manifold and valves. I am not to keen on fluid dynamics but I know there is a way to run lines and not to run lines for each sprinkler to get the same pressure. Example: One station (zone) to have four sprinkler heads. One inch pipe branching off the one inch manifold, going to a junction. Where it would drop down to three quarters to each head with each line of three quarter equal in length. Am I correct or smoking my lunch, any suggestions.
RE: Piping size versus total output
1) What is your pump head at 5 gpm assuming the pump needs all hp at 50% efficiency. The actual power requirement may be less as well as the efficiency.
1/2 * 1714 * 50% / 5 = 86 psi --> 199 ft of water
This is very likely a multistage deep well pump.
2) How deep is your well (x) subtracting supply pressure and friction in a 1" pipe. Assume 150' of distribution piping after well water is at grade.
86 psi - 30 psi - 0.85 (x + 150) / 100 = x / 2.31
54.725 = 0.424 x
x = 130 ft deep well. This is deeper than you neighbors, could their wells be 50 to 75 meters deep?
3) You can force as much water through a pipe as long as you have the head to overcome friction losses. Let's see how much water (y) can be crammed through the 1" pipe with a 1 hp motor and maintaining a 30 psi system pressure. This is a system of 3 unknowns and 3 equations.
1 * 1714 * 50% / y = z
z - 30 - f(y) (130 + 150) / 100 = 130 / 2.31
Approximately y = 9 gpm, z = 95 psi, and f(y) = 2.6 psi/100 ft
RE: Piping size versus total output
RE: Piping size versus total output
Only 30 psi in the house? I set my switch to run the pump at about 45 psi and shut off at 60 psi. I still get temperature fluctuations when in the shower and the wife turns on a faucet. I think the house plumbing is to blaim--is a mobile home.
Good luck!