Closed-loop system for extracting THC with butane

[donpsychote]

Hi,
after several successful extractions of honey oil from marijuana with liquid butane I'm now considering a closed-loop system. It would have several advantages over pipe or bottle devices.
I'm envisioning a modified refrigerator. One would have to take the entire refrigerator's loop and equip it with a detachable extra chamber for plant material and a modified evaporator with a detachable module for removing oil. There would have to be extra hand-operated valves placed into the loop.
After some research on refrigerators I found out that there indeed exist refrigerators with butane as the refrigerant. They are kinda back in vogue because of environmental concerns with CFCs. Special care has to be taken to separate electrical elements, as sensors etc. from the butane loop to avoid sparks.
My question is, is that feasible given a sympathetic mechanic that would do the modifying work? Or would I be just better off to buy a compressor and design the thing from scratch?

[Osmium]

The amount of coolant inside a fridge is actually pretty small, it's only a few grams. You would have to install an extraction chamber which could be opened, valves to isolate it from the butane-filled part, and some means to get the oil out (oops, you said all that yourself). You also have to make sure that your extraction chamber will not contain any air before you let it run. Finally, the fridge pump contains an oil, and you have to somehow make sure it won't contaminate your product!
Sounds pretty involved to me, you could only extract a small quantity anyway amd the butane would constantly have to be replenished.
I'd rather distill the butane off and condense it with CO2/acetone. You might even build some semi-continuous apparatus, but I doubt it's worth the trouble. I'd rather try to find a good and cheap butane source.
Or experiment with other solvents, e.g. first extracting all the goodies with hexane, and then extract this stuff with butane (after being applied to an absorbent like SiO2, cellulose etc). Well, you could also investigate chromatography, which allows you to reuse the hydrocarbon solvent.
I'm not fat just horizontally disproportionate.

[thethethe]

Don't they use semi-large tanks of butane on those buffing machines you find, late at night, polishing the floors of Wally World?

TTT
Drug shortage is a worldwide problem with neighborhood solutions.

[lab_bitch]

It looks like your trying to do something requiring a knowledge of chemical engineering.  If you're not a chemical engineer, then it may be a difficult task.

[terbium]

I'd rather distill the butane off and condense it with CO2/acetone. You might even build some semi-continuous apparatus, but I doubt it's worth the trouble. I'd rather try to find a good and cheap butane source.
Or, another alternative, if you are working on such a large scale that you want to recover solvents then use pentane, hexane or low b.p. petroleum ether then you can distill off the solvent and recover it using a condenser cooled with nothing more than cold water.

Baseline Does Not Exist.