Sorry for intruding but can I ask a question. Can someone tell me please
how much water roughly will travel through PVC 40 pipe by gravity (no pump),
if it's vertical (roughly) and only about 6 ft high? In a few different
diameters? I've looked on the internet and I can only find tables of
friction loss and tables of maximum flow rates. I just want to get an idea
for an aquarium system that I'm building. i.e. with 1/2", 1", 1.5", etc.
I appreciate any and all help.
On Sun, 06 Mar 2005 00:57:34 +0000, quietreef wrote:
The formula for figuring volume of a cylinder is 2 pi r squared times
In the case of 1/2" inch pipe 72 inches high that would be (2 x
3.14 x .25squared) x 72. Which would give you 28 1/4 cubic inches. 1
gallon(US) is 231 cubic inches. So that would give you .1223 of a gallon,
or about a pint.
That's how much water it will hold. How much water will travel through the
pipe depends on whether it will be at full volume for the pipe and how
long a period of time you are looking at. For a 6' length of pipe,
friction loss is minimal for an aquarium.
Are you asking how long for a certain amount of water, or how much water
in a certain amount of time?
I'm looking for rate. If the water is falling by gravity with no pump
or back pressure, roughly, how many gallons/hour will I get in a 1/2"
pipe or a 1" pipe, which I assume is 2X whatever the 1/2 number is.
Now that you've laid it out so nicely, I should be able to figure it
You mixed up the formula. It is pi r squared NOT 2 pi r squared. 2 pi r
is for circumference.
You need a different formula to figure out the flow rate anyway (but you
willuse this calculation also). You need the pressure of the water. In
a vertical pipe you get 1 PSI of pressure for every 2.33 feet of head
(height). You'd be at about 2.5 PSI at 6' (without a calculator). I am
still looking for this formula, but if will give you cuft/sec. Then you
can use 7.48 gal/cuft of water to calculate gal/sec.
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