Gravity flow in a mine shaft
Gravity flow in a mine shaft
(OP)
I am trying to calculate the flow rate by gravity in a 1" sch 80 pipe in the shaft of one of our mines. The pipe is 4300 ft long with a 4300 ft elevation diference, effectively all of the pipe is vertical. Currently we are allowing one tank on surface to feed the tanks under ground at about 75 l/min by gravity alone. I would like to determine the expected change in internal pressure and flow if we add a pump to the surface supply. The fluid is diesel and the delivery driver tells me that he has done it before and he is unable to increase the flow rate even though the pump on his truck can supply up to 50 psi.
Thanks
Thanks





RE: Gravity flow in a mine shaft
RE: Gravity flow in a mine shaft
You may need to give a little more data (e.g. temperature, type diesel etc.) to get a more accurate response from the more learned folks on the forum.
RE: Gravity flow in a mine shaft
While this may seem minor, don't forget to take into account the increase in air pressure at the lower elevation. 4300 ft vertical should yield an increase in elevation air pressure of about 2 psi, unless the mine shaft is somehow kept at atmospheric pressure.
RE: Gravity flow in a mine shaft
I didn't participate and have been unable to find it, maybe someone who participate will be able to find it.
RE: Gravity flow in a mine shaft
Because all of the potential 1550 psi is being consumed by friction losses it means that the potential additional 50 psi that you could get from the truck offloading pump is trivial. And the 2 psi of additional air pressure at the bottom of the mine is even more trivial. Your uncertainty in pipe diameter and roughness will far exceed this.
I suspect that the earlier thread to which UncleSyd referred is thread378-81608
regards
Harvey
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Gravity flow in a mine shaft
Regards
RE: Gravity flow in a mine shaft
Between this thread and the archived one above I've resolved most of my concerns.
Chris
RE: Gravity flow in a mine shaft
I got 1550 psi by saying 4300 ft diesel = 3600 ft water = 1550 psi approx. I.e. this is the static height only.
Harvey
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Gravity flow in a mine shaft
Cheers,
CanuckMiner
RE: Gravity flow in a mine shaft
Chris