Hello everyone,
In my state I’m having an finding dry ice. I was thinking about an alternative to using a vacuum pump without a cold trap, any suggestions? I’m using this for a 5L SPD. The thing is I did some searching about diaphragm pumps, but I heard that they don’t pull vacuum as large as a rotary vane? Is there a pump out there that would be as good as a rotary vane, but can avoid using dry ice?
Thanks everyone for your help! really appreciate it this is my favourite forum.
Buy an immersion cooler for your cold finger. Not as cold as dry ice but it will keep you going
Any recommendations on brand? Also do you remember the price for it by any chance?
We use this chiller for a cold trap on one of our vacuums at work. It does the job.
Edwards has a high dollar dry pump that will get you down below 10 micron.
Immersion chiller. Dry ice and acetone manage around -55 on average. Anything warmer than -50 you aren’t doing much to protect pumps. Short path pump and process micro plane molecules right off the surfaces of cold traps. Immersion will keep you cold enough (-90) to protect pumps and manage micro planing.
I use a -90 immersion chiller and if you bought the small block dry ice maker, youd be set. The immersion chiller will pay for its self in a matter of weeks. I guess depends on how much you run
Only in a specific core temp, and under certain conditions. In atmosphere and with a heat load you should see around -50 or a bit more on the internal surface of the glass.
You talking about that dry scroll thing? NXds20 ic I think? I use one for my vac oven, I don’t know if they get down to 10 micron but that thing sounds like a truck backfiring on startup. Sucks like a demon though, just get an exhaust muffler if you’re ever in the market for one of them.
Has anyone tried that trick where you dunk your exhaust bellows hose in a bucket of water with dish soap in it to scrub the poogas? I have a hard time believing that pump could survive unprotected sex with a 5L mantle full of ethanol crude.
I don’t believe feeding a dry scroll ethanol or terps would do it any favors. I’ve got pictures of one around here that probably died from inhaling liquor at some point (not actually sure what killed it).
Good to note that one cold trap isn’t enough, 2 will do it though
Not sure if it would help
But many school labs use water powered vacuum pumps, also air driven vacuum pumps for volatile solvents.
Also I believe I’ve read about gravity assisted vacuum. But can’t remember lol until I get more coffee in the brain
I used to use an aspirator pump for my rotovap, they’re actually really cool for sucking up volatiles but they can only pull a vacuum as low as the vapor pressure of the liquid they’re circulating. You could fill one with pump oil and get down pretty low, but you have to refill the res pretty often as you’re sucking all kinds of fouling that will continuously raise your vapor pressure, killing your vac level.
There’s gravity assisted aspirators that hook up to a sink faucet that I used in school, terrible waste of water and you’re never going to get below -10 inches.
Ya I was thinking the nXDS20i it’s a 10k dollar pump the literature says down to 22 micron? I would still want to protect the thing but I’m only going off what I’ve read I’ve never used that pump.
Dry scrolls can be good roughing pumps but still need a cold trap if you care about your expensive pump.
For cannabinoid fractions, atleast one 2 stage rotary vane is recommended.
Thank you for all the great suggestions everyone! I will do my research to see which solution fits my budget.
