@Dred_pirate That def makes things easier having the chiller on your solvent Tank…
@J12 I Understand know why your using the coil inject for Passive with that Solvent tank on Legs, How cold is your Slurry on your coil? Not sure how that dont stall out… I think With Passive less is more. Shortest lines possible With a Subzero Taking the Heat…
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I totally get it. The other tank could do it if you wanted if you had the means. You have your own way.
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probably -50 ish it’s just dry ice and alcohol. my lines to and from the coil are 5 feet each. my collection vessel is jacketed and when i flow hot water into the jacket i let the tank warm up until it gets to 45 - 50 psi then open up the ball valve for recovery. it has plenty of push to go into the coil and keep things flowing. The first 2/3 return pretty quickly and the last 1/3 i periodically shut off the valve to get a little more pressure in the tank and then open it back up to get the last bit of tane out. During the beginning of recovery i also have a purge line connected to my tank open until liquid starts flowing into the tank and then close the purge valve after things are flowing. that helps get a nice flow going for me. I also think that helps prevent lock up because if there is any pressure in line that your not aware of its purged out of the tank and allows for good flow
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and check valves chatter…sign of work being done!
One thing i’m confused about is how much it has been said to pull a vac on your tanks. I’ve always been led to believe you want zero atmosphere in any component attached to your system which is why we vac everything, including our solvent tanks as deep as possible before filling or running.
Can you confirm this is a correct way to think? @Dred_pirate
For example my tank will be filled with 50lbs of solvent and maybe sit at 10 psi @ room temperature, and when I drop the temp of that tank to -75 it will be damn close to full vac regardless of how much solvent is in it. If I didn’t vac the tank before filling and left some atmosphere in there would that not condense from the cold and be creating pressure?
I’ve witnessed my dewax column filled to the site glass at the top (110% overfilled) and still reading a -25 vac with maybe 3 inches of headspace in a 2" siteglass head.
So surely, as long as I can keep my tank chilled to -75, and my collection/jacket can heat the solvent efficiently it should be screaming to get to that coil and tank.
I remember reading in summit closed loop 101 that running passively renders molecular sieves almost useless because you lose turbulence / starting and stopping of solvent through the filter. Is this old knowledge? Should I still run collection → mol sieve → coil -75 → tank -75?
Much appreciate all the knowledge in this thread. Definitely going to give this a shot and have a feeling like I won’t be looking back at active or rebuilding another fucking pump 
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If I’m understanding you correctly, there should be zero atmosphere in your solvent tank. That’s why we vac everything down as well as for the pressure differentials that make passive recovery possible. I am curious about the mol sieve though, as that’s something I need to be investing in asap.
However, I’m curious as to its (mol sieves) utility if you are purging the system with nitrogen prior to pulling vacuum. I would think this would remove all the atmosphere and 99% of the h20 from the system.
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Purging with nitrogen wouldn’t really remove any water. We run passive with a mol sieve. The pressure drop through the beads is almost nothing
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Anyone else using a Tankless water heater? I like this idea. Can you Use it with a bucket of water or do u need a hose for constant pressure or a PUmp? I see a few on ebay for less than 200$ for an electric tankless water heater seems like it might be alot more efficent than an immersion circulator…
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Constant water input
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Have you looked at the electrical requirements for those things.
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@Dred_pirate It seems the little guys are same specs as the Vacmaster sous… 1500w 110v for the little guys… i did notice alot are 3200w 220v. Id have to run another dedicated circuit for the bigger ones…but Im guessing that the Little Water heater would be more efficient at keeping the temp Constant compared to a couple Vacmaster Sous. Considering there about the same price I might give it a whirl…
@greggoose710 THANK YOU… So ill still need the pump…
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That’s pretty dope. I would be interested if they would work. Keep it far enough away from the extractor so there wasn’t a boom boom problem.
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Most of those should be run off of propane or natural gas. Even Home Depot sells them.
hey very useful info just a quick question i am stalling on recovery and seem to be doing everything you are detailing my solvent is 40/40/20 eco green mixture i don’t know if maybe i should be using acetone for cooling my coil to get it colder since i am not using pure ntane
I just use DI and alcohol with my coil. what psi do you let your system get to before recovery?
it usually gets to about 50 psi before recovery
i also read you mention you have a purge line at the beginning of recovery open can you explain that?
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you can purge the line in a few ways. If your system allows you to connect the lines and pull a vac on them then you can do that as it’s the most preferred and safe way. If you can’t do that you can simply loosen the line right before the valve on your destination vessel (while the valve is closed). From here you can open the valve from your collection pot and let some gas push any atmosphere from the line, then just tighten it while the gas is coming out. It’s a ghetto way of doing it but it works in a pinch if you can’t vac the lines down.
I usually do the latter because I don’t have enough lines at the moment. Just be careful throttling the valves when you’re purging the line and you’ll be fine.
you can hook up a purge line to your recovery tank that relieves it of pressure so your recovered solvent has no resistance to coming into the tank. once you got a good flow going close the purge line and let it do it’s thing. Your tank should start pulling vac on itself if your recovered solvent is cold enough. i recover once i get to 35psi so 50 is plenty
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What are you connecting to the purge line, and what are you purging off?
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ok i will try that for sure next run
next thing is i inject with a 1/4 inch hose my injection is always really quick then the hoses from material column to collection vessel is 3/8 inch hose but from my collection vessel to recovery tank is 1/4 inch again i am contemplating upgrading that to 3/8 inch hose maybe that will help with recovery because my recovery times are horrible
Thanks for the help!!!