Siphon inside keggle doesn't work

[ramz7887]

I don't know why its not siphoning out the last parts of water? Its has a 90 degree bend and is part of a 3 tier system. Should the kettle be a little higher? I thaught that it would create a vaccum from draining out a full kettle and be fine even though there is not much of a height change

 

[blackwaterbrewer]

i am battling the exact same thing right now. i got some advice on here, but either it was incorrect, or i did't understand it correctly. i hope this gets some replies. i know there is a solution. if you keep your thoughts open to the force, the solution will always present itself.

 

[ramz7887]

óh also on the bottlom i cleaned up that rust on the edge with a brush. How long does SS have to wait before it rebuilds its protective cover, a week?

 

[ramz7887]

I was thinking about using a auto siphon (like the ones for carboys) to help pump out the water by connecting a tube from the spigot to the bottom of the pump. I'm was gonna do this on my bk since the temp will be alot lower but I know you can't use it with really hot water. I was maybe thinking about maing one out of metal so it can handle the heat and kinda do a vaccum style HERMS system.

 

[lehr]

It looks like your pick up tube is at an angle if so it will break suction early also you outlet hose end needs to be lower than you pick up tube.

Pat

 

[Zen_Brew]

I believe in plumber speak it is called long leg / short leg. The hose on the drain side must be lower than the hose on the siphon side, and longer in length. From the pics it looks like you just have the drain hose straight out from the drain valve. You might need to raise the keggle 6 inches or so, then make sure your drain hose hangs lower than the 90 degree bend inside the keggle.

 

[ramz7887]

here is a bigger picture. The welds are water tight.

 

[ramz7887]

Yeah I pushed it back down so it does not angle out. Shouldn't the height not make a difference since the vaccum should just contineue to pull out water since the seal between the bottom and the end of the spigot is not broken.

this is the bottom of my boil kettle

 

[Zen_Brew]

Shouldn't the height not make a difference since the vaccum should just contineue to pull out water since the seal between the bottom and the end of the spigot is not broken.

Nope. The initial flow starts from the pressure of the wort on the tube. Once the level gets to the bottom it does rely on a vacuum, but the vacuum requires the exit hose to be lower than the level of the remaining liquid.

Here is a brief definition from Wikapedia.
A siphon (also spelled syphon) is a continuous tube that allows liquid to drain from a reservoir through an intermediate point that is higher, or lower, than the reservoir, the flow being driven only by the difference in hydrostatic pressure without any need for pumping. It is necessary that the final end of the tube be lower than the liquid surface in the reservoir.

 

[ramz7887]

Yeah its the flexability of the tube that creates the vaccum

I guess this will work then when I can clamp down the ends

So I can fill up some kegs

 

[bendavanza]

I lose suction early, especially from the brew kettle to the fermenter. Using the venturi style aerator has not helped. I wish I had more distance between kettles. Sometimes I wonder if 1/2" tube is just too big for gravity setups. Maybe if I put a restrictor in line to keep air out of a long enough "long leg"?

 

[ramz7887]

so you've tried what i wanted to do with the boil kettle and a siphon?

 

[Dr_Deathweed]

It looks like in that picture you are draining into a cooler/mash tun. Siphons work by differences in hydrostatic pressures (as explained above), so as you drain the keggle the water level in it drops, and as you fill your cooler, the water level rides. Even though your hose may technically be lower than the end of your pick up tube, if it is submerged in water in your cooler it is still working against the pressure of the water in the cooler, and can only drain to that level. In other words, the levels in your cooler and your keggle are reaching an equilibrium, and since there is no hydrostatic difference between the two at that point, the siphon ends. Recommendation: Lift your keggle a few inches, or lower your cooler a bit to re-establish a gradient between the two.

If that does not work, that you probably have some kind of air leak in your setup which is breaking siphon, but I don't think that is the case here.

 

[ramz7887]

I think i'll get a few bricks and raise the kettle up a little. The tube is forced on top of the t- join with the top of the T open during the drain. Do you think the open top hurts? I was planning on pouring a couple of runs through it during mash out so that i could clarify the wort.

 

[jeffmeh]

The open top of the kettle does not matter. Get the lowest point of your siphon drain well below the lowest point of the kettle, and that should work. If it does not work, you have a leak somewhere that is letting air get in to break the siphon.

 

[lehr]

I lose suction early, especially from the brew kettle to the fermenter. Using the venturi style aerator has not helped. I wish I had more distance between kettles. Sometimes I wonder if 1/2" tube is just too big for gravity setups. Maybe if I put a restrictor in line to keep air out of a long enough "long leg"?

No the 1/2 inch line is fine I drain from my boil in my garage through the foundation of my house in to my fermenter in the basement with 1/2 inch and it will drain the boil almost dry. You just need the outlet lower then the pick up.

Pat

 

[IrregularPulse]

I had this problem once my water level go to the level of the spigot it would stop. This was with just the valve open, no hose attached. I added a length of hose to go below the pickup point, voila, drains the keggle dry.
You're output hose needs to be lower than the pickup point. The lower point will be where the system siphons to once started.

 

[ramz7887]

i put a brick under each leg of my burner and it was enough of a height increase to solve the siphon problem. I forgot about the tubing adding to the effectiveness of the siphon, problem solved!

 

[ramz7887]

stupid physics!

 

[Spine]

I had the same issue with my keggle as well. I ended up silver soldering a 3/4" FPT to 1/2" solder fitting to the bottom of the keggle and then drilling out the hole after it was soldered. It was the best thing I did. now I can drain my kettle to absolute empty and I don't have to worry about siphon physics. I wish i knew about this earlier before I spent all this money on weldless fittings which I don't use anymore!

 

[Yuri_Rage]

If we're gonna get all excited about physics, there is no vacuum involved in siphoning, just differential hydrostatic pressure. Mostly, I'll shut up now.

 

[Rick500]

One comment... you don't want to use a metal brush on stainless steel unless the brush is also made of stainless steel. You'll get ferrous steel in your stainless steel and that'll cause rust.