Weight of water

[1930]

I have a 2" PVC pipe with an inside diam of 2.067 that is 100 feet long.

Also within that same pipe is a second sealed 1" pipe that has an outside diam of 1.315 same length.

How heavy will the water be?

My intention is to push that column of water from the bottom to the top and I need to know this answer so I can plan the rest of the pump accordingly.

Please dazzle me with how you came up with the answer. Thank-you

 

[Streetcar]

16.65 pounds
Larger pipe area is inside diameter squared times pi divide by 4 subtract the outside diameter squared times pi divide by 4
Divide that number by 144to convert to square feet multiple by 100 to get cubic feet multiple by 62.4 pcf for water to get answer
Done on cheap small calculator so I probably have fat finger mistake in final answer

 

[oldballs]

Fat finger or not................lI'm impressed.

Cheers,
Mike

 

[Tinhack]

The weight of water will be ~8.34 pounds per gallon.

The water will be the same weight if it's in your hand, a glass or in a pipe.

 

[Egon]

If it’s vertical at STP you will need at least 43.3 or more psi of air pressure to move it all in one slug.

 

[s219]

Is the water only in the annular space between the two pipes, ie, inside the big pipe but not inside the small pipe? If so, I calculate 86.56 lb of water in that annular space.

Weight = [area, ft^2]*[length, ft]*[density, lb/ft^3] = [(pi/4)*(2.067^2 - 1.315^2)/144] * [100] * [62.4] = 86.56 lb

Now, that said, if you want to size a pump, the weight isn't important, the pressure at the bottom of the water column is. That would be 6240 PSF or 43.3 PSI.

 

[RalphVa]

The 86 # is what I get, too, and agree on the 43.3 psi.

 

[3Ts]

That 43.3 psi is only if the pipe is vertical. If he's running up a slope it will be less. The formula is 0.433 * elevation change. Depending on the rate of flow (gallons per minute) there will also be pressure loss due to friction in the pipe.

 

[BRMyers]

Just a simple quick way to roughly figure out PSI is take the height and cut it in half. It will give you a rough PSI not taking into account friction loss. So a 100 ft rise would be 50 PSI.

 

[SPYDERLK]

Just a simple quick way to roughly figure out PSI is take the height and cut it in half. It will give you a rough PSI not taking into account friction loss. So a 100 ft rise would be 50 PSI.

Good tip. Easy to remember. Just dont forget thas its rough.