Pure math help(calculation of flow from siphon)


Precipitous120's avatar
Hello

I have a farmers problem, again, I need to calculate the possibility of siphoning water from a bore hole without using electricity

The math...

The bore hole is 60metres below the siphon point

The length of pipe going up to the siphon point is 16m

The siphon point is 50.5 metres long

The slop up and the slop down is the same making the difference negligible

The diameter of the pipe is 5cm or 0.05metres

This is a system pumping water.

Ok I think that is everything you need. Come on lets see some genius answers out there !
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Larry952's avatar
i see what you're wanting to do.  i don't think it's going to work for you.  you might consider a windmill, which can lift water from a well to a storage tank.
Larry952's avatar
siphoning works by gravity.  the source of water has to be higher than the water's destination.  in other words, you can siphon water downhill, but not uphill.
Precipitous120's avatar
Siphoning water up hill has been done since the time of Rome
Larry952's avatar
can you cite an example of uphill siphon?  from everything i've read and done, the destination must be lower than the origin.
Larry952's avatar
the article you refer to is about the human heart.  nothing to do with siphons.
Precipitous120's avatar
it is lower down on the page

Sorry for sending such a rubbish reply in the first place... I was using my phone but still that is no excuse.
Precipitous120's avatar
Sorry for the weird link but I promise the information you are looking for is there

www.ck12.org/book/human-biolog…

I'm using my phone right now so sorry for the poor uhm information gathering
DoctorV23's avatar
The pipe going up basically needs to be shorter than the pipe going down, but I'm not getting a clear enough idea of the setup here.
The pipe diameter is also very large - that's a lot of weight - I'm afraid that your pump will have trouble priming the siphon. Just a 1 meter length of 5 cm diam. pipe will contain 1.963 kg of water. Handy site: www.inchcalculator.com/pipe-vo…
Then there's the problem of barometric pressure: www.nature.com/articles/srep16…
An alternate scheme might be a holding tank at a higher level that you could pump water to easily enough with a garden hose, albeit it would be slower.
We do that with our rainwater cisterns that then give a gravity-only water supply at about 1 atm to the house. It works well. Pump runs for an hour at a time, maybe 2 or 3 times a day if needed.

-Our main collector is the roof and the water then goes to another cistern under the house. This explains it in detail: www.vandf.gr/index_files/Rainw…  
Precipitous120's avatar
Thanks for the links

We already have an existing pump and storage system in place. The idea is to change that into a siphon pump instead, like you said the pump can't pump for long without overheating.

The existing pump has all the parameters I gave, and it indeed has a shorter length of pipe going up than down.

I just needed to know if the math worked. I did my own calculations and they said the glow out of the siphon would be 1000 metres of water per a second. Which I thought was too high, probably meaning I calculated it wrong, but it could actually be right.

Considering the tons of water, that alone could siphon the water.

I guess I should just do a test run but it's a lot of work to do just to fail.
DoctorV23's avatar
It's a question of physics as well, though. If the source is a deep borehole, a siphon cannot work - there a working limit of around 10m height maximum due to barometric pressure, so you do need to pump it out. If your storage tank is higher than the place you want to use the water, That will work fine with simple gravity. You don't even need a siphon.

Otherwise, you might want something like this: www.tanks-direct.co.uk/water-t… - locate the tank at a high position (rooftop, or up on a hill?) ...  that's how we work in my neck of the woods. :)
Precipitous120's avatar
We already have such a system in place

It isn't good enough

Hence siphon

Still I find your mention of barometric pressures being too great interesting

If the siphon works I'll he happy to inform you that you are wrong :D

Otherwise I'll gladly thank you for the heads up that all the hard work to come might just be for nothing :'D
cactuscowboy's avatar
Why don't you use a car battery, a siphon pump and a hose. It works for garden fountains. Or you can always reach back to antiquity and try an improvised archimedes screw of some sort.
Precipitous120's avatar
The whole idea is to pump the water without electricity

Pumping water for prolonged periods puts strain on the pump.

I'm guessing a medieval screw is going to require constant kinetic energy.... So that isn't going to be effective either

Still your the only one offering solutions so thanks

The reason we need to pump the underground water is because we are going through a drought here. The weather has been extremely unusual lately

Last year we had rivers freezing during summer and 100℅ humidity when the temperature was only 9 degrees Celsis

Now for the beginning of this year we have droughts which is very strange considering this is the UK.

The idea is to pump the underground water up to the dam so we can use that water to irrigate the crops
cactuscowboy's avatar
Couple the screw with a solar powered device like they do with traffic lights and road signs. How big is this pump your using—are you talking industrial size or more your basic lawn mower garden variety size.
Precipitous120's avatar
A bore hole pump

But again even industrialized pumps break if run constantly..

Hence why I need the math behind the siphon instead of alternative solutions
cactuscowboy's avatar
Are you speaking about a Jet-Pump system?

Do you have a system in place now? And if so, how have you been operating so far?
Precipitous120's avatar
It pumps about 10 000 litres every 2 hours

But if you leave the pump on for 24 hours it breaks

We have had to replace it once before which is how I know as much

We need to effectively fill up a dam with ground water because there is a drought here currently

Which would cost too much electricity and possible go through many pumps

Which is why we need to siphon instead.
cactuscowboy's avatar
With those numbers your irrigating a good size piece of land. We had a guy here in our city that was pumping roughly about the same amount of water from our aquifer to run a catfish farm when city stepped and shut him down after they couldn't negotiate a price for the water usage.

I don't know what else to tell ya buddy. Good luck.  
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