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Bi Directional Flow Question?

Discussion in 'Concentrates & Processing' started by dabarino, Feb 22, 2017.

  1. IMG_2904.PNG I'm thinking about making a passive (for now) bi-directional flow upgrade to my closed loop... I understand most of the theory of it butane enters the bottom of the column above the ball valve then floods from the bottom up giving a more consistent soak all the way through. Then coming back down through a hose to the collection pot then I know you flood the top like you normally would to collect the remaining oil but with what butane do use to do your top flood with do you recirculate the oil soaked stuff you just filled the column with or do you introduce more butane into the system to flood the top with? Any help would be appreciated..... let's use the set up in the pic as a diagram

    My guess is use new tane but I also think that maybe wrong?
    GT21 likes this.
  2. dabarino likes this.
  3. rascali


    yes, all rinses are with "clean" butane from your storage tank. If I may ask, where did you snag that pic? (if you're running cyro you might want to add a relief valve to that top tree!)
    dabarino likes this.
  4. That picture is from best value vacs 1lb mkv bi directional flow unit.. I was going to build something pretty similar to this just a little more basic... I am running cryo but please explain why you would put a pressure relief valve at the top of the tree... and how much extra butane would I need add to the system? would I double it? Is that why i need a relief valve Because of all the extra tane if I'm not running cryo I would be running to high of a psi?
  5. ASME requires a pressure relief valve on LPG pressure vessels. If a flooded column is valved off and heats up, expansion pressures can be extreme.
    MirrorZen likes this.
  6. gotcha @Graywolf.... what about the butane amount how much more would i need to add to the system for the top flush and would i use the normal amount on the bottom flood?
  7. so lets say i start with 2.5 lbs of butane normally would i flood through the bottom with 1.25 then seal everything up and flush down the top with another 1.25..... 2.5 is already more then i need as well
  8. The amount of butane required is a function of how much material is extracted, and as a rule of thumb I plan on about three column volumes of flood and ASSume the packed column only holds about 70% of an empty column.

    I typically put two column volumes through the bottom by timing how long it takes to overflow the top and then flooding that many minutes again, before opening the dump valve and rinsing that long from the top for the third volume.

    Bottom flooding gives the best uniform wetting, so the combination of bottom flood with top rinse, typically gives better yields.
  9. so basically .76 lbs twice through the bottom and .76 lbs once through the top to rinse..... this should be a good starting point and ill add more if needed thru timing ... do you recommend putting the sight glass at the top of the column? it makes sense to me since most of the oil laden butane will be traveling up not down.
    1.5" X 24"
    (35 Cubic inches)

    • 0.76 Lbs.
    • 571 mL (1.9 Cans*)
    Plant Material
    • 146 Grams (0.32 Lbs.)
    *300 mL. Cans
    **Butane = 0.60126 G/mL.
    TriClamp Size: 1.5"

    TriClamp Height (Inches): 24"
    Packing Density (Cubic Inches): 4.2

    column calculator-
    Last edited: Feb 26, 2017
    TerpyTyrone likes this.
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  11. When you guys say 'cryo' do you mean co2, N2, or both/either? How do you keep the butane viscous enough at such low temps with just passive pressures, or is that why you've been talking about LpG?

    Also how does this bi-directional process affect quality? Honestly my washes are usually so conservative there's enough left in the material that's it's worth giving away to reprocess for charity. I know I leave a good bit on the table, but economy of time dictates I spend energy on other tasks.
    dabarino likes this.
  12. when i say i "cryo" i mean a simple home made cryo fluid like dry ice and 99% iso rubbing alcohol. it turns into a thick napalm like substance and its suppose to get to about -77 c.. but my temp gun only goes to -38 so im not 100% on my actual temp... i can do a passive recovery at that temp on 2.5 lbs of butane in about 20-25 mins and thats pulling a slight vac on the extractor when im done
    MirrorZen likes this.
  13. thanks graywolf ill look into one of those threaded sight glasses. as far as the metaglass a 2" one goes for about 500$ where im from so i dunno about those lol
  14. Me too on all that, except I thought the co2 slurry was only about -40ish, and mine is more liquid than gel. Also I use denatured etoh instead of iso. I need a better temp gun too, mine only goes -10.

    My weak link for pressures was that oversized column. What temp is your water bath?
    Last edited: Feb 27, 2017
  15. I Do my water bath on the hotter side like 110-120 but I also drain my dewaxing column of cryo fluid and fill with same temp hot water... and the more dry ice I add to my slurry the thicker it gets.... it gets like molasses if I add enough
    MirrorZen, CelticEBE and Graywolf like this.
  16. I typically use the word subzero rather than cryo, because while the N2 or DI may be at cryogenic temperatures, we don't operate at them. I've used both liquid N2 and DI and prefer liquid N2.

    Down to -40C we use a gas mixture up to 50/50% n-Propane to both lower C-30 pickup, as well as to lower viscosity so that it continues to flow.

    We've also used a hot pot for pressure, by which you place a tank of LPG in 110F water and connect it via the vapor valve to the vapor valve on the LPG supply tank, so that it adds head pressure during injection.

    Biflow improves yield, and allows both extracting for yield or top quality. If I want to make museum quality bragging rights extracts, I make about a one volume flood from the top for the sample, and then extract the rest as a separate operation.
    MirrorZen, rascali and Herb Forester like this.
  17. We typically make a cotton candy extraction and run our water bath at ~70F <85F and during recovery, flood our column jackets with 150F water.
    dabarino likes this.
  18. Well if that's how you do er, I'm gunna have to give her a go like that myself.. I'm thinking those temps were adding a little color to my end product as well.. its been a little bit prone to waxing around the edges if you turn the heat up to..
  19. I do this quite a bit unless I'm trying to make some "museum quality product" it speeds things up so much.. just take the tank out every couples mins and give it a good shake you can drain 2.5lbs of butane out of your tank in a few mins... just make sure you got a gauge on your tank before you start sticking it in hot water trying to build pressure..
    Graywolf likes this.
  20. How do you "take a sample" do you close the ball valve with the column still pressurized? And scrap the collection pot then re vacuum the bottom half?