Water syphon

I agree about possibility of crack in the line.With that much pipe, to prime this system you would have to pump out a fairly large volume of air...rough guestimate being 1/3* volume of the pipe = pi*r^2*L= 1/3*3.14*(1.5*in/2)^2*600*ft = 18 gallons of air.

Therefore if their is a leak in the pipe, air would rush in while you are trying to prime the process and you wouldn't be able to reduce the pressure enough to get the water flowing.

Is the pipe rigid ? A soft hose type pipe would collapse shut..I'm assuming you aren't trying to do that. Other than that...a blockage is probably your answer.

Maybe you could try to send positive pressure (using a regulated air pressure source) to see if you can bubble air through the pipe and into your water tank. If you can control this pressure you can see how many PSI it takes to get the bubbling started. If it's more than maybe 5 psi...you probably have a blockage or a serious leak.

Hope that helps

To help you with your siphon problem I need some additional information, essential to calculate your siphon status.

1-1/4 inch... does it mean the nominal pipe size? Pls give the actual, real inside diam. of your pipe.

"Poly pipe." Do you mean a hard polyvinyl-chloride (PVC) pipe or what? What is the inside condition of this pipe... clean and smooth? How many pipe sections are in your 600ft pipe line. How are the sections connected to each other?? How many elbows are in your pipeline. (All of the above is about calculating the flow resistance, which is critical in syphon lines.)

Your intake side water level. (not the suction pipe end) By how much is your outlet pipe below this water level. 22 feet?

"and the line goes up and down a few times//"

What is the HIGHEST point of your pipeline ABOVE THE SUCTION SIDE WATER LEVEL. In feet or meters.

Dear Mr. Loki,

The Bore of the pipe such as as I.D, is NOT a depending Parametre, for SYPHON effect. What is essential condition to be fulfilled to create SYPHON EFFECT and thereby Flow of Liquid, is a PERFECT VACCUUM is to be created at the Down-Streme of the pipe.

If it is very small pipe, a person can suck and create vaccuum and establish SYPHON EFFECT. Once Vaccuum is created, the atmospheric pressure will push the liquid in to the pipe as long as the Height is below the Barometric Level, and liquid will flow. Frictional Head loss is to be duly accounted, and the Effective head may reduce. For bigger pipe and lengthy pipe, vaccuum creation is to be arranged.

But the length given is 600 Feet, which obviously JOINT is to be provided and it should be ensured that there is NO AIR-LEAKAGE, through the joint. If air leakage is happening, that will rupture the Vaccuum, and air rushes in, and hence Syphon effect and hence flow is LOST.

Secondly, at the liquid entry point, some air due to SWIRL may enter and rupture the Vaccuum, and Syphon effect and hence flow is LOST. To avoid this, the liquid entry point in to the pipe should be immersed to the extent of 300 MM or equivalent to avoid SWIRL FLOW.

I have read once a very minor leakge of air will not cause problem, air entry to the extent of 7% Volume of Liquid, will totally rupture the SYPHON EFFECT.

DHAYANANDHAN.S

This is a good reply, but confusing.

'Guest' put it well when he said to make sure all the pipe is full before starting the syphon.

What I do is have a valve on the end, fill the tube while it is laying down flat in a coil, have it coil up so all the air can get out. Then stretch it out down the hill with all the ups and downs.

When all is set, and the up end is firmly in the suction tank, open the valve.

Having valves on both ends is even better. That way it doesn't get a drop of air in it. Air can reeealy stretch and mess up a syphon.

It also depends a little on which poly tubing is being used. If its a very soft wall plastic, the walls might collapse and close off the water flow long before rising 30 feet. It amazes me how some simple machines, perfected by brilliant ancient men and women can still be botched today using the latest technology.

Dear Mr. Mike,

Providing a valve out the out let is OK. In the ups and downs of the pipe contour, the air will NOT be properly removed from the CREST(S) and hence PRIMING will NOT be proper.

The requirement is, even 1 cc or 1 gm OF AIR SHOULD NOT REMAIN INSIDE THE PIPE AND TO BE EXPELLED. So AIR RELEASE VALVE is to be installed at the crest, of the pipe line. For draining SCOUR VALVE at he bottom most Point between 2 crests, is to be installed.

I have experience of 14 years of maintaining 13,200 Metres Length of 250 MM Dia. Asbestos Pipe (which will break easily) handling 40 Litres/Second CAPCITY.

DHAYANANDHAN.S

What is your poly pipe? is it a hose or pipes joined together? From your start is the slope downwards? How many curves are in there and how is the radius. If you have no leaks (where your siphon is taking up air) flows easier than water, and the pipe/hose is not restricted or collapsed, try to prime from the high side under water. Pump water through the pipe under water and remove the pump hose. Your water should run if the run is not too long. In the worst scenario 1"1/4 over 600 feet can give you very little water. Smoothening (straightening)the pad will help. The inner wall causes loss, and so does every curve. If too much of everything maybe one lucky drop of water remains?

I've used 1 1/4 poly to siphon over a 8' rise and then down to a 5 hp centrifical pump and then down about 15 to 20' over a 1/4 mile.

The pump is used to prime. The connections are critical!!! Use silicon on the connectors and tighten to the max with gear clamps. Make a bypass (optional but much recommended) of the pump with ball valves to eliminate vacume leaks through the pump and provide an unrestricted path during the siphon mode.

Running the pump for at least 10 min or more to get the water flowing would keep the siphon running as long as 3 to 5 days as the flow gradually slows to a stop.

It is maybe not clear in my explanation, but I should try to press the water through the siphon first. Pump outlet on the water supply side and under water. This will purge the air better out of the system. Where do you use this system? Are parts of your line exposed to heat from the sun or other heat sources? (Sometimes dark rock) Especially the down run? If this is too long the "thermo- siphon" action (water heated flows upwards) can also stop your transport.

Your story intrigues me. A next theoretical approach is the permeation character of your tube. (possible cause for your time collapse) With reverse osmosis water is pressed through a membrane. Air passes easier through a membrane than water. We measure air moisture with permeation tubes. Hyper dry air with a dew point (1 ppb Volume) of minus 160 celsius is easily contaminated with moisture, even in stainless steel, polyurethane tubing, pvc tubing and less through aluminum and heated red copper. You have created a very big pipe "surface" that is maybe permeating in time. Many factors in your process work together against all odds and can make it a critical setup. You will probably find a solution. We don't mind here if you let us know too.

If you work backwards, may be you can eliminate a lot of doubts such as trapped air....

Connect a pump to siphon outlet and pump water upwards to water reservoir above. Once the line is full take away the pump.

Alternatively at the pump discharge you can keep a vent line, which you can open after the line is full so that vent line will be the drain line for the syphon.

Good luck. Keep us informed how you solve this problem.

Siphon problems: air in the pipe, air leaks at the joints.

Tell us what means you have to fast flush the pipe from bottom to top with bubble-free water. A submerged pump is best. A hose is next best.

If the air is gone, there should be about 11 psi pressure at bottom.

Flow, however, depends on friction of water in pipe. 600' is a long run.

Make sure there are NO leaks by observing as the prime pump is running. I repeat, any leak of water is a leak of air which will stop the siphon very quickly.

If you can pump a bubble-free stream from bottom to top, and there are no leaks, when you turn off the pump, the flow should reverse, and go top to bottom IF you had enough flow to flush the air sections out.

I bet it's a leaky joint.

This exactly was my point . See comment No 10.

Good answer for that - my money is on very large friction being the main problem for a pipe of this diameter over that distance. It isn't unusual for friction to entirely stop a flow - OP needs to do some maths with a Moody diagram.

Friction comes into play only when there is a flow. When there is no flow the friction drop is zero.

You may have a few things going on here, one is the internal friction of the pipe over that distance negating the head to the point that the siphon is broken, the other may be the water is degassing this will be dependant on the flow and fall and the water being siphoned, this will gradually degrade the effective head until it fails. Could you make the sypon over more than one drop as you have a "few ups and downs"?

Try laying pipe over route with both ends open, blow into ext it end and get someone to observe intake end for bubbles.

also from your notes it sounds like you have filled the pipe with water and closed taps ar each end then placed intake end into liquid and exit to where ever you want and opened taps you do know that you need to suck at exit end to start siphon don't you?

sorry if it sounds insulting but we need to build a picture of whats not happening to work out what to suggest

Have you tried blowing down the pipe with a breath of air to test the actual resistance you getting? or a pressure gauge while priming with the pump? The ID might be too small and you getting too much resistance(similar to a volt drop) through the length of pipe. In that case you would get a VERY reduced rate of flow but certainly not nothing.

Just my 2 cents worth

Madness, certainly madness... trying blow air through a 1.5 in 600ft long pipe.. Perhaps you need a few African elephants..

Hey do not take my words serious. I could not resist the fun.

Coming back to serious business.. my guess is that our guest is nor priming his pipe/tube properly and/or pipe/tube is restricted in the middle due to warping. If the 600ft is a soft walled hose very likely the latter

You did not say where your syphoning the water. Is it a small bore well or a pond?

If you are syphoning from a well that is indicating water at 22 feet you may have to extend your intake deeper into the water so it will not break syphon. The theoretical lift by syphon at 1 atmospheric pressure is about 33 feet. A practical lift is less due to vapour pressure and pipe friction. Your 1.25 inch poly is assumed to be a standard polyethylene smooth wall and 1.25" is inside diameter. This is a common pipe used in drilled well applications. Friction head loss in the described pipe is 0.4 ft/100 at 5 gpm. Lower your intake pipe beyond the 33 feet so that the syphon cannot be lost. A drilled well with a static level of 22 feet (as measured from the top of the well to the water surface) is likely the result of a slow recovering tail in the overall production of the well. The well yield if measured in the top portion of the well may take much longer to recover than from a much deeper level. Another consideration is the volume of water required to fill the pipe. In 1.25 " pipe it will be 1 US gallon/12 feet. It is possible that the well would see a drawdown (level measured from the surface after water is pumped, syphoned or drawn ) below the syphon lift possibility of less than 33 feet.

I would suggest you syphon the well (or pond) in two stages. The first stage will be from the well to a storage tank. Make sure both ends of the syphon will remain submerged at all times. The reservoir is to provide small storage that the well or pond could trickle at low flows to fill. A second syphon could then be activated to draw water from the new reservoir at a desired rate for a limited period of time. You would have to locate the fill pipe from the well below the outlet for the second syphon. The outlet for the second syphon should be float controlled so it does not break syphon.

If you are drawing from a pond you can still consider the second reservoir and double syphon. A second consideration may be a pump called a coffee jar pump. This is a clever idea and can be viewed at:

coffee pump

I do stress that both ends of the syphon remained submerged at all times. The coffee jar pump is only a shallow lift pump and it is restricted as a syphon would. Have fun and let frustration be a cause for persevering. Just smile as you get peed off.

Kevin,

You specify one atm as 33 feet but that is only true at sea level. If the OP is doing this at ten thousand feet, the lift will be much less because of the lower atmospheric pressure at that level.

OP,

What is the altitude of this project? How are joints in the pipe made up? Any leak at all in the above water length of the pipe will cause siphon to be lost. If the altitude is not sea level, the maximum lift of the siphon will be reduced by the lower pressure.

Have FUN!
TT3

You are right. I was only qualifying my statement with 1 atm.

10000 feet!! If you go up that high try to remember to let the air out of your tires.

With an 1 1/4 inch pipe air will back up into the pipe if that is possible. Therefor your siphon can not terminate in an open end and still work. If this is the case currently then that is likely your problem. Terminate the pipe in a stationary reserve like a bucket or pond. Then the siphon will maintain the air lock. The gravitational potential for this siphon is fairly low being only 22 ft. When established correctly the flow will begin slowly and gain speed over time. Bends and even curves add greatly to the apparent "length" of the pipe. A straight run should pump. A curved or kinked one may or may not depending.

Dear Friend,

You referred " The gravitational potential for this siphon is fairly low being only 22 ft."

You know SYPHON is working on account of ATMOSPHERIC PRESSURE which is EQUAL TO 34 FEET of WATER COLUMN. Now 22 Feet is 64.7% of atmospheric column, even 6 Inches difference also will work since the driving force is the ATMOSPHERIC PRESSURE.

Hence 6 Inches or 6 feet or 22 feet has no impact. Frictional loss is ignored here.

DHAYANANDHAN.S

Hi,

Assuming that the pipe is clear (no obstruction, or collapse of pipe wall,)
and, that at no point does the pipe rise more than 20+ft above the inlet,
then the water will flow.

I find the easiest way to do this is to temporarily seal the bottom end of
the pipe, leaving a small aperture hole in the seal, and then fill the pipe
(obviously) from the top end. When the top end overflows i.e. the pipe is full
(which is the critical part) of water, place the top end well and unmoveably
into the volume to be syphoned. (usually with a small weight will be sufficient)

If the base of the volume has the potential to block the pipe in anyway, e.g.
a muddy lake, weight the end of the pipe to keep it down; and also attach to
the pipe (approx. 2 foot from the end) a float. (e.g. empty plastic container)
Usually it is far easier to prepare this before filling the pipe.

With the top end immersed, to complete, release the seal at the bottom of
the pipe, and water will (should) flow for ever more!

Only if... the top end of the pipe is released from the volume of water,
(to let air into the pipe) or, there is a fault in the pipe (hole to let air in)
can the water stop flowing.

This system is very easy to implement correctly done; and I have
emptied huge lakes, containing many thousands of gallons of water, -
and all for no cost! (where others have used expensive pumps, etc.)

Working with nature is wonderful. (don't fight it.) Hope this helps.

jt.

Ooh, I just thought of a way you might be able to troubleshoot this siphon. I think somebody here identified that your hose will hold 18 gallons of water. Regardless of the actual number let me use this as the the hose's volume. Take a tub with at least 30 gallons of water in it, but a known amount (I'll assume 30 for now). Place the siphon outlet in a container at the bottom of your run and that you can measure the volume of water that completed the trip. Then use your priming pump to start the siphon. At the moment water covers the output opening (2 gallons of water, so no air enters), stop the pump. If no more water appears at the siphon output and water does not back into the 30 gallons so that 10 gallons remain in the tub and 2 gallons reached your outlet and nearly 18 gallons lie in the hose, your hose is intact but the rise in height is too great some where for a siphon to work. If instead more water flows toward the outlet and water flows back to the source then you have an air leak in your hose. Also the ratio of how much flowed into the outlet divided by how much flowed back into the source should tell you how far away from the outlet the air leak is.

Clever thinking. I like your trouble shooting logic. However, if the pipe is the poly pipe that I am familiar, a leak is highly unlikely unless OP has used connectors or other mechanical joints and the leaks will likely appear at these joints. Polyethylene is very rugged and can even be driven on (not recommended) and survive. OP has not said if he is siphoning from a drilled well or a reservoir. If it is a well, the drawdown of the well could exceed the siphon head capability just filling the pipe. We had a similar thread about 5 or 6 weeks ago with a drilled well. I suspect the siphon attempt is very close to limits and any change will stop it. That was why I suggested a double siphon. Checking for a leaky pipe is still a good idea though.

If this is black poly pipe, on a sunny day it may get quite warm. This will decrease the vapor pressure of the water, thereby also reducing the height it can be lifted. Near the upper part of loops, it even possible for the water to boil. Just as with air leaks or entrainment, this will break the siphon.

With a steam table, you can find the vapor pressure at various temperatures and calculate the theoretical height of lift, which might conceivably be less than 22 feet.

600 feet is a long distance pressure difference of about -300psi- but without going through a number of calculations first try a simple test.

Fill the pipe with water and let it syphon for shorter height less than 30 feet. Then block the outlet and put the pipe into the tank you want to empty - make sure no air gets in or no water is lost when introducing the pipe into the tank (it is tricky I know).

Then take the pipe outlet where you want and open the end.

If the water syphons fine if it does not I guess the 600 feet drop is creating a negative pressure of 300psi and trying to boil the water and hence vapour creation stops the flow of water.

The head that is trying to 'push the water' through the pipe is 22 feet - approximate losses in the pipe as I calculate it are about 5 - 6 feet of water. So there is still a net head of 15-16 feet. Water should flow through that. The losses are based on circular pipe so if the pipe is kinked or flattened the losses will increase.

I placed a comment under guest #30 where I mistakenly thought the drop was 600 feet but the test is still valid. Fill the pipe with water and then introduce it to the tank ensuring no water is lost or air let into the pipe. The water should flow!

Check Wikipedia for this Hagen–Poiseuille equation to determine if your pipe diameter is large enough. And as others have said prime the pipeline from the bottom end. As you can imagine if you prime from the top end the water can flow over the humps leaving air in the top of the hump. If you can't do this raise the bottom end above the highest level of your pipeline e.g. 25 feet up. once the water flows out and the air is dispelled you can then lower it and it will siphon if the diameter is large enough.

sorry for late response. my in laws have about 500 foot 1 1/4 siphon. black poly pipe. the problem starting was the same as yours i think in the beginning. the cheap hose connectors /plastic barb/ hose clamp. on the connectors look and see if there is a small round circle just about where the end of the hose should be.[barb portion] these have to be cut off [filed] and smoothed off. it causes a deformation which may not leak under pressure, but will allow air in. there are 2 on each connector. use 2 hose gear clamps, at opposition to each other on each side of the connector. good luck.

Dear Friend,

NATURE will follow its rule, and will NEVER and will not DEVIATE. Once SYPHON effect is created- the liquid flow will be perfect. You have not mentioned the following, and pl. mention the same.

1. How did you prime.? Is it by pouring water, by blocking at the down-streme.?

2. While priming, the down streme is fully closed or partly closed and water was flowing out.? If so, the Priming is NOT PROPER. At the crest of the pipe line air lock will occur, preventing syphon effect creation.

3. Have you provided air lock valve at the crest in the up-level of the pipe.? If so the air valve will automatically release the air and once air is removed, the valve will block the passage of water through the valve.

4. Is the pipe immersed sufficiently below the water level so as to avoid SWIRL EFFECT, where air enters in to the system, and disturbs.

I am sure , the problem is around the PRIMING aspect.

Pl. post information, how did you solve the problem.?

DHAYANANDHAN.S