Bell Siphon Problem

bluefin

i can only guess whats happening because the restrictor is out of view during the syphoning process. I asume that water is passing through the bore of the 12mm and around the sides of it ass well. It would still have to be a restriction as the water would swirl and eddie at that point. ( where 20mm meets 12mm) Water could be running through the 90mm return at the time but not necessarily, depending what is happening in the gb, upstream. They fill at different rates depending on vegatative growth presence of root mass etc.

KudaPucat

Just to confirm...
Like this???

bluefin

like what?

bluefin

yes thats it i believe that is whats happening, nice diagram.

KudaPucat

So the 12mm pipe just 'floats' there. it is not restrained by anything?
the 12 mm pipe has no endcaps
the 12 mm pipe need not sit in water.

Does the 12mm pipe need to be straight? or can I use a bit of black poly I have lying around, with a slight bend?
does the pipe need to be free to move? ie the bend in poly may wedge it in place.
does the pipe have to be central?
does it matter what diameter you use? I have 25mm standpipe, do I need to use 19mm restricter?

does it matter how far the 12mm hangs out the bottom of the standpipe?

KudaPucat

bluefin wrote:

yes thats it i believe that is whats happening, nice diagram.

yeah you'll see in stage two, if it happens that way, that an airlock has been created. I think I'm understanding how this might work.

bluefin

bent or straight 12mm doesnt matter. The 12mm just sits there. i asume it would be fairly central. It is not attached in any way. It may or may not sit in water depending on upstream flow. beleive me it works!!!

KudaPucat

OK, now I'm sure I know how to build it, I am going to try and restrain myself from building it tonight :-(

I have a problem in that I need to get ready to go on a 4 day hike, leaving this evening, but I want to build siphons!!! What's wrong with me?

Food&Fish

bluefin wrote:

ok. I used to install a lot of urinals and associated pipework. The wall mounted cisterns used an autosyphon. At the bottom of the flush pipe dilivering water to the urinal face is a restrictor called a sparge that directs the flow accross the urinal. The sparge is usually a chromed cast brass fitting with an inlet in the top for the pipe and a narrow slot the width of a hacksaw blade for the outlet. When the cistern fills and the autosyphon starts to overflow the water gets to the outlet but is restricted the water starts to back up in the pipe untill the syphon kicks in. The restriction no longer seems to affect the flow and with a gurgle and hiss the water rapidly drains from the cistern and disperses across the face of the wall. Coincidentally if you remove the restriction on the end of the flush pipe it is near impossible to get the autosyphon to work correctly. So back to my bathtub setup. My empirical findings would lead me to believe that the 12mm pipe which has a gap around it of approx 3mm and is just sitting loosly in the standpipe will allow water to pass around it and through its bore. The water backs up in the standpipe and then must reach a point where the volume collected in the standpipe is too great for the restrictor to hold back. The syphon kicks in and water is able to pass through and around the 12mm pipe with ease. It does work. I can cut the level of flow into the bath right back and the syphon still kicks in. Without the 12mm pipe i need to crank the flow up to get the auto syphon to work. The pump is delivering 18000 lts per hour through 40mm pressure pipe to 11 outlets controlled by 20mm ball valves. I will take some readings this arvo and post them tonite when i get home from work. Try it out you will be amazed the difference it makes. Oh i guess it would be similar to inverting a bottle of water and spinning it rapidly. the water dribbles out initially and then a vortex happens and the bottle drails in a flash, maybe? I will try to post another diagram later.

dont understand that does peeing in your system come close

KudaPucat

Well, resistance is hard. :-(

I tried it. I think my pipes were too long though, cos water covered the top of the bell, but the siphon refused to start :-(

Out of time, bother about it next week.

jessy

keep it simple KP....you'll never go wrong

( now for an ear bashing ) :oops:

KudaPucat

Web4Deb

If I may interject...

Web4Deb

oops....hit Submit!

I believe this is how Bluefin's work.... It's the same way a loop siphon would run....but it's nice to remove the "bell" for maintenance...

1) Water gets to the level of the standpipe
2) Water trickles over the pipe...and through the restrictor...no siphon yet.
3) water continues to rise in the tank, making the water go faster through the pipe. Once there is enough flow, the restrictor creates a vacuum which then....
4) sucks the rest of the air out of the bell (or loop)

I will still argue that you need enough supply flow for the GB to get enough water to create the vacuum in step 3. With a true bell system, the trap & burp allows for a quick gush to start the siphon.

OK, I'll put on my bullet-proof vest now..... :mrgreen:

thorn

So the addition of the "helper" piece (does it have a proper name? like Frank? ha!) aids the start of the siphon by creating a tighter vacuum restricting water flow and it aids the end of the cycle with the slant allowing it to be an airbreak. Will have to test that when I get around to my bigger system.

Would a T at the bottom work for holding the extra piece? Or does that constitute too much resistance from the turn (as an elbow would)?

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Bell Siphon Problem

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