Page 1 of 1

2" Shotgun PC issues

PostPosted: Tue Apr 16, 2019 12:14 pm
by icewind
made a 500mm 2" shotgun PC with 5x 1/4" pipes for my 4800w pot keg still. Condenser sits at a 45 degree descending angle.

AFAIK, did everything right. intake runs from bottom to top, vapour goes down through the 5 smaller pipes as the water fills around them. Yet I am struggling to keep the distillate cool past around 3600w. Water basically needs to be running very fast (think turning mains tap on half way), and even then at 4800w distillate still comes out hot (not quite vapour hot).

I'm somewhat perplexed as I thought 500mm with 5 pipes should easily condense 4800w. Will become somewhat less of an issue once I complete my recirc system but i'd still like to figure this one out. :think:


edit: condenser is cool to the touch up to about half way or further up.

Re: 2" Shotgun PC issues

PostPosted: Tue Apr 16, 2019 1:03 pm
by hillzabilly
I think that 5 by 1/4 inch inner tubes is the issue,consider the extra surface area ifn you had used 1/2inch tube would be over double of what you have,I would add more 1/4inch tubes if possible or just use power that you know will not overwhelm what you have.cheers hillzabilly ;-)

Re: 2" Shotgun PC issues

PostPosted: Tue Apr 16, 2019 2:08 pm
by woodduck
I agree, 1/4" would be a bit small I recon.

Re: 2" Shotgun PC issues

PostPosted: Tue Apr 16, 2019 2:10 pm
by The Stig
What temp is the cooling water going in ??

Re: 2" Shotgun PC issues

PostPosted: Tue Apr 16, 2019 3:04 pm
by 78Monk
Purely for comparison, I have an identical sized shotgun but with 1/2 inch internals. I run 4400w in a stripping run and use 1.5 — 2 lpm from the hose running just a bit over pencil thickness. Distillate is cold. Condenser is hot at appox the first 5 - 7cm.
Disclaimer - I'm a noob and have run my pot still 3 times since the vinegar and sacrificial run.

Re: 2" Shotgun PC issues

PostPosted: Tue Apr 16, 2019 5:44 pm
by Permaclutter
Another one for comparison. I have 7 x 12mm in 2" by 400mm PC on a pond pump and am thinking it is contributing to the reflux by cooling the block head,6Kw. Maybe think of all these things as heat exchanges used in clever ways, and at your dimensions for the given vapour speed you have more like a hot water service than a gas cooler. Heaps more 1/4" or drill them out to 1/2' and i'm sure you will be fine.
Cheers and good luck.

Re: 2" Shotgun PC issues

PostPosted: Tue Apr 16, 2019 6:05 pm
by Permaclutter
Please ignore me, it was a rubbish comparison, as i have never tried running it as a pot. Tomorrows job.

Re: 2" Shotgun PC issues

PostPosted: Wed Apr 17, 2019 1:30 pm
by icewind
thanks for the tips guys. What do you mean drill it out to 1/2"?

Re: 2" Shotgun PC issues

PostPosted: Wed Apr 17, 2019 1:43 pm
by RC Al
I would build a new one for stripping and keep that one for spirit runs, or rebuild it with twice as many tubes, 1/2" or 5/8" (dn15/dn18) is really the way to go

Alternately you can daisy chain another condenser on to the end, a liebig is easy enough to knock up or add a same size shotty in 1/2" and a couple of more elements for stripping :music-deathmetal:

you cant drill 1/4" pipe out to 1/2" but the shell could be and 1/2" used instead

Re: 2" Shotgun PC issues

PostPosted: Wed Apr 17, 2019 5:19 pm
by hillzabilly
icewind wrote:thanks for the tips guys. What do you mean drill it out to 1/2"?

De-solder and remove your 1/4inch tubes ,then drill out the holes ta suit 1/2inch tube and fit and solder them in place.cheers hillzabilly ;-)

Re: 2" Shotgun PC issues

PostPosted: Wed Apr 17, 2019 5:55 pm
by icewind
i see! ... i had visions of boring out the 1/4" pipes like you do a cylinder head. :))