5' head drop,300’,4" pipe If I reduced the pipe to a smaller diameter over the 300’would I get more pressure?

Question

5' head drop,300’,4" pipe If I reduced the pipe to a smaller diameter over the 300’would I get more pressure?

Answer 1

Nope... if you want more pressure at the end of the pipe, you want to increase the pipe size so you have less pressure drop. If all you have to work with is 5 ft of head, that is not a lot of pressure to start with. As a rule of thumb, 1 ft of water is about 0.4 psi, so if the 5ft of head is water, you have about 2.5 psi minus the pressure drop in the 300 ft of pipe.

If you want more pressure you either need more liquid head or you need a pump.

Pressure drop is a term used to describe the decrease in pressure from one point in a pipe or tube to another down stream. This is usually the result of friction of the fluid against the tube. Tube convergence, divergence, turns and other physical properties will affect the pressure drop. High flow rates in small tubes give larger pressure drop. Low flow rates in large tubes give lower pressure drop.[

Answer 2

If you reduce a pipe's diameter, but keep the volumetric flow rate the same, the head loss will *increase*.

That is, the smaller the pipe, the more work it will take to force fluid through at a given volume flow rate.