# How do I turn Litres/hr and drop into PSI?

OK heres what I'm doing I need to know a formula to tell me how much drop in an inch and a half hose and how much length, to get me 620L/min out of a stream I have about 300' of hose and about 15' of drop to work with so far i can also increase the length with some 3" hose about 200' with an added 10' drop what kind of PSI would both give me. I have cleaned out and cut off the bottom of a 45gallon drum and plan on making a dam and attached the inch and a half hose to the 2" bung on the top. anyone got any other ideas?

I'm kind of lost in the details of your venture. However I can answer your primary question.

PSI or pounds per square inch, is a pressure. Pressure is independent of flow(except for Bernoulli conditions not used here).
This simplifies it down to just converting the drop(or head) into PSI.

It appears that you have 15foot of drop;
convert to meters: 4.57200 meters
density of water: 1kg/L or 1000kg/meter^3
take 1000kg/m^3 x 4.572m= 4572 kg/meter^2

4572 kg/meter^2 is a pressure, simply convert to psi-----
divide by the conversion 1m^2= 1550in^2 to get
2.95 kg/in^2
then multiply buy the conversion 1kg= 2.2lbs

*It is probably quicker with English units, but I tend to steer clear of them whenever possible.

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