First I will start with CLS specs and say that I have done a lot of searching to find this information and have not yet stumbled upon it, I have a 5lb system that is rack mounted with a molecular sieve.
My question is regarding prepping the system after a run for the next run. After removing spent material from the material column and reloading how can I ensure butane has been evacuated from all parts of the system before pulling a vacuum in preparation for my next run, as I obviously don’t want to pull butane through the vacuum?
Upon opening the system after individual runs there are small amounts of butane lingering in the collection vessel and molecular sieve. Should I nitrogen flush the entire system and then pull my vacuum?
A Venturi vacuum would solve that issue…
I just run nitrogen thru the column before vacuuming because I don’t have a Venturi.
They sell super cheap ones but the good ones that get enough vacuum are 200-300$
A pneumatic/venturi vacuum pump is the right answer. You should avoid pulling major amounts of gas through it as it’s hard on the seals and will also gunk the pump. But, pulling vac is the practicable answer for back to back runs. Depending on what temps you are running, you could flood nitrogen through the system and still leave gas behind. Beads tend to hold gas even when heated/vac’d to a degree, so it’s best to just have the safe vac pump.
Explosion proof vacuum pump. Air powered is relatively inexpensive.
Assuming some things about where you’re running, you could use a water powered Venturi on your garden hose. Or even a trs-12 with the outlet vented to atmosphere (somewhere safe)
Doh! Missed that one! Definitely makes sense. What would you consider an acceptable level of vacuum? Still haven’t played the butane game so just curious for academics sake.
Routinely pulled to 1000um last time I had a digital gauge.
@Photon_noir had numbers in that range (1200um and 800um iirc) that he trained folks to once upon a time.
Luna Oberon I’m playing with now has digital read out, but it’s in in.Hg and analog gauges have trained me not to pay attention to values in in.Hg.
The advantage of using a digital gauge in microns is that you can see leaks almost immediately… And can eventually tell the difference between biomass offgassing, residual solvent in the tube, and Actual leaks
Personally. I’d just leave the wax in the collection pot and leave the entire system with butane gas left in it from the last run. Just vent the column. And the only thing you’ll have to vac down is the column. Leave the bottom of the column connected to the hose that runs to the collection pot. Unless you don’t have valves to do that.
I’ve done this for years. And you don’t need anything special that you don’t already have
Also I have been sucking out residual butane with a hfs regular old vacuum pump for years. It’s fine if it’s just a little residual left in there.
Cole parmer makes a few, so does air vacs
Using nitrogen to supply it would be the safest, as using an air compressor introduces oxygen to butane if you suck any out, and oxygen and butane at the right mixture would probably = flame thrower, if it ignited.
With a venturi you sacrifice speed for vac depth, but choosing the one with the deepest vac will likely recover faster, I’m uncertain if that equates because the extra time spent pulling the vac could be spent recovering at a slightly slower speed
Are you changing what strain or source of material you’re using between these runs? I only ask because you mention an empty collection with residual butane present.
If you are not, @Slabby has detailed the best process, just leave the butane atmosphere in your system and let your recovery tank take it out later or let it reduce when the temperatures are reduced again if that’s your process flow.
I would only caution while many of us have used rotary pumps to remove small or even sometimes large amounts of residual butane from environments either on purpose or on accident without harm I don’t think it would be prudent to recommend it.
If you simply want to vacuum down your new column any pump will do since there will be no residual butane vapor left in it after you’ve removed and replaced the material if you have a good sop.
Now, if you are instead discussing after changing strains and you want to maintain strict adherence to cross contamination prevention, you’ll need to first flush everything out, pour what you get from that until you can pour with no residue and recover your collection vessel to a ‘full’ vacuum with no residue. Now it’s ready for the next strain/source.
My last paragraph should cover that. If you need something more detailed hmu in the DM and I’ll give you a free run down. If it needs to be more involved than a decent text explanation we can make it a consultation.