New Pot Huffing on Cool Down

[eternalfrost]

I just finished my first alcohol run on a new potstill i made. it was a stripping run and went fine. the new libig was able to knock down all 5500W into a nice even stream.

but when i shut down the power i noticed a "chug-a-chug-a" noise near the output when i was cleaning up the jars. nothing loud but easily noticable when your heads close. putting my hand in front of it there is a pretty sizable poof of air coming out on each "chug". sounds like its sucking in and out, about 2 times a second.

im not too worried about it as the run itself went flawlessly just wondering whats going on as ive never heard of this and this it the first time ive run a legitimate pot still not a detuned column

[Dnderhead]

Cooling and creating a partial vacuum?

[Hack]

I'll bet you're getting a vacuum like Dnderhead said. On my setup with a thumper I need to crack the seal on the column immediately after killing the heat or the vacuum will siphon the juice from the thumper back into the boiler.

[Hawke]

I think, if I was to add a thumper, I'd also add a ball valve somewhere on the pot or riser to break the vacuum. Not fond of slip joints and flour paste anymore, so my parts are easy to break down, just not quick to do.

[eternalfrost]

I know its a vacuum effect...

im just wondering whats causing the oscillations. because its just a simple keg to 2" reduced to 1/2" to a liebig, all open.

because its fairly intense, about like if you purse your lips and hyperventilate haha

[rad14701]

Was your liebig drained when this happened or was there still water in the jacket...??? Also, was the rig positioned to where it could get hit by drafts of cool air...???

[eternalfrost]

Was your liebig drained when this happened or was there still water in the jacket...??? Also, was the rig positioned to where it could get hit by drafts of cool air...???

there was still water in the liebig shell but not flowing. no air drafts.

[FarSideStill]

pot is cooling, air rushes in to fill vacuum.
new cool air in pot heats up, expands, and blows out.
That's the best i've got...

[punkin]

You could either open the refill port or leave the water running till the vapour stops flowing ...5-10mins...

[eternalfrost]

its not causing any problems just an interesting and unexpected behavior.