engineering help needed for siphoning project

[GrogNerd]

I'm trying to empty my above-ground pool and can't get to the drain plugs. they're underneath the edge of the bottom and the weight of the water won't let me to them to open

so... to save the money of buying or renting a pump, I'm going to DIY myself a siphon

hope the drawing makes sense, but here's the explanation. 4-foot section of 2" PVC pipe inside the pool, connected to a 4-foot section of same size pipe, connected by a 90° and a T fitting. The T fitting has a plug on the top

at the bottom of the outside pipe is another 90° to the 2 5-foot sections of pipe, connected together by a flex coupler and ending in a ball valve. flex coupler is there to let the valve end of the pipe run down a slope to the fence, and ends below the level of the bottom of the pool

the plan is to shut the valve and fill that side of the siphon with water to prime and capping the top of the T. then, when the valve is open, there should be enough pull to that water rushing out to start the siphon & empty the pool

hope I'm not overlooking anything, but could use some better minds (or you all) to double-check my work

Thanks

 

[arturo7]

I'm thinking you'll need the pool side full of water as well, but I'm not a hydraulicist. ...unless it comes to ingestion...

 

[GrogNerd]

going by what wikipedia says about siphoning, I'm using the principle illustrated here, with its caption

under the presumption that water level A is irrelevant (inside or outside the pipe), as long as the water flowing from the upper reservoir is past point C and has reached the same level in the outside pipe as it is in the upper reservoir before the air gap reaches the end of the outflow pipe. or, if that is not correct, I've added enough pipe before the valve so the water should be past the bottom level of the upper reservoir before the air gap reaches the valve. that should be enough to keep the siphon going

"Air Start Siphon - When the column of liquid is allowed to fall from C down to D, liquid in the upper reservoir will flow up to B and over the top. No liquid tensile strength is needed to pull the liquid up."

 

[day_trippr]

I'd add a foot valve at the bottom of the pool end...

Cheers!

 

[TheDudeLebowski]

The draw will happen as long as it is lower than the pool. Once it's equal it will stop (the bottom). So are you just trying to empty the pool and then fix the plug? Or find a permanent fix?

 

[BrunDog]

What will probably happen is once you open the valve, air will displace the water leaving the end of the pipe. That will continue (air into the pipe, running along the top and the water running out, along the bottom of the pipe.). This will happen until the whole pre-filled column is empty. Per day tripper above, you need a valve at the pool end so you can fill the whole siphon with water first.

 

[GrogNerd]

Fail.

It's drawing water from the pool, but loses siphon rather quickly. It's loose fit, not cemented, so maybe too much air being drawn in.

Then i dropped the plug into the pool. NOT going in after it

May have to go with day_trippr's foot valve

 

[BrunDog]

Sorry! Why not just use a sump, drill, or fountain pump to drain it?

 

[iijakii]

Fail.

It's drawing water from the pool, but loses siphon rather quickly. It's loose fit, not cemented, so maybe too much air being drawn in.

Then i dropped the plug into the pool. NOT going in after it

May have to go with day_trippr's foot valve

I don't really see what the foot valve would solve if you're breaking suction from air intake at the top there. You really should just try and tape the threads and go again.

Or for more fun bust out an air compressor and try to get some venturi action going, heh.

 

[beermanpete]

Why not use a garden hose? I know it will take longer to drain the pool but it will not have any air leaks. Let it run all night if needed.

 

[GrogNerd]

I'm trying to empty my above-ground pool and can't get to the drain plugs. they're underneath the edge of the bottom and the weight of the water won't let me to them to open

so... to save the money of buying or renting a pump, I'm going to DIY myself a siphon
Thanks

View attachment 417305

Sorry! Why not just use a sump, drill, or fountain pump to drain it?

maybe I didn't think of using a pump

 

[GrogNerd]

Why not use a garden hose? I know it will take longer to drain the pool but it will not have any air leaks. Let it run all night if needed.

guess I didn't mention, it's pretty nasty water, almost like a pond with leaves and I'm sure there's critters living in there. if I weren't afraid the hooks would tear the vinyl, I'd fish in it

 

[TheDudeLebowski]

Just dunk the garden hose in the pool in a way that let's all the air out of the hose and fill it up with water. Stop it up with your finger so no air gets back in and pull it out of the pool. Make sure it's long enough that the weight of the water in the hose creates enough suction. Just remember once the pool water level matches that of the output of the hose you loose the suction. Try to find an area to drop the output of the hose that's lower than the bottom of the pool. Use do it all the time as a kid with our pool. You could also suck it with your mouth but in afraid we'd need a video of it ;-)

 

[flattie]

Why not use a garden hose? I know it will take longer to drain the pool but it will not have any air leaks. Let it run all night if needed.

What he said.

Unroll your hose.
Turn on the water at your spigot.
When water comes out the other end, drop that end into your pool. Tie a weight to it so it stays near the bottom.
Turn off the spigot and remove the hose from the spigot.
Drop that end on the ground.
Water will flow out that end and it should start a siphon.

 

[GrogNerd]

5/8" ain't gonna cut it. not with the leaves and gunk in it

 

[TheDudeLebowski]

False bottom? 😁

 

[beermanpete]

If you are hoping to take the siphon apart when done you might try sealing the joints with a bead of silicon caulking on the outside of the pipe. You could take it apart later by cutting the silicon bead with a knife.

 

[TheDudeLebowski]

Have you tried one of these:

 

[arturo7]

At this point ya gotta ask, what is the budget? You can go to McMaster-Carr and buy a length of 2" tubing for $2/ft. Or start bailing and call it exercise...

 

[GrogNerd]

spent about $40 so far. about what it would have cost to rent a pump from D&B for a day

about 1/2 what I would have spent buying one at Harbor Freight, which probably wouldn't have lasted a day

 

[DrunkleJon]

Two queations and possible answers

Does this pool have a pump? If so just back flush to waste. Otherwise pull the return hose from the outside wall pf the pool and let it drain halfway.

Does the pool have a vacuum? The hose from that is usualy about 2 inches. Prime with water, cap with your hand, remove from pool and place lower than pool and let go. Instant flooded yard. Far better than a garden hose.

You can also get your pc monstrosity working but the diameter is probably to large. Just grab several garden hoses and place the ends in a coffee can full of holes in the leaf strainer to seprate the crap from the gross mosquito breeding ground you have.

 

[balrog]

2” Shop vac hose. Do a siphon the old fashioned way. Brute force FTW

 

[Bobby_M]

Do you have vac hose for cleaning the pool? Tie a weight to the end, drop it in the pool. Leave the other end on the ground and put your garden hose in the other end to force all the air out. Pull the garden hose out and it will start draining.

 

[GrogNerd]

Do have a vac hose, will try that

 

[dzlater]

I took my garden hose.
put a shut off valve on one end.
filled the hose from the tap.
shut the valve.
disconnected the hose from the tap, put a shut off on that end.
so I had a hose full of water.
tossed one end in the pool , opened the valves.and siphoned away

 

[Scout]

What will probably happen is once you open the valve, air will displace the water leaving the end of the pipe. That will continue (air into the pipe, running along the top and the water running out, along the bottom of the pipe.). This will happen until the whole pre-filled column is empty. Per day tripper above, you need a valve at the pool end so you can fill the whole siphon with water first.

Yes, depending on the slope of the pipe. I would add a 90 just going straight up to keep that pipe full. And he might need to lengthen the pipe going downhill to get it started.

Yeah I know it's an old Post.

 

[lschiavo]

And the pool is a sweet skating rink.