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Plate Bypass

If you wanted to quickly change a plated column still into more of a pot still, might running an exterior pipe from the bottom bubble tee to the top bubble tee do the trick? How would the exterior vapor path interact with the internal path through the plates? Would the plates still be producing (undesired) reflux or would the vapor find an easier path in the bypass? I suppose the answer is probably a mix but I was curious to see if anyone had any reaction to the idea.

Comments

  • I've seen it done using 3-way valves to pipe the vapor either to the column or directly to the condenser.

  • Yeah, that's probably not possible with a mounted 8" column (that would be one huge 8" valve) which was why I was trying to think of an alternative.

    If you want to run as a pot for a whole run, disassembling the column/removing plates is the best option of course, but the job isn't for the faint of heart (unless an overhead lift system is available).

  • Maybe an 8" condenser below the bottom plate and use a 2" top port to pipe to your product condenser?

  • Actually what happens is that initially the vapour takes the easiest path, through the bypass. This disturbs the pressure gradient so that where it is possible, each plate dumps its contents. With perforated plates they drain. With bubble cap plates with weep holes they will drain.

    All possible vapour paths are then used to the top of the column. I am putting external valves on my own column so I can do this, but each valve will disable a single plate. This is to give me a bit more versatility in plate count - if I will ever need to use it is still open to discussion.

  • SO IF you had a3 or 4" sanitary fitting oposite the sight glass you could plumb most any kind of bypass setup on the back side of each plate... that's where my knife gate valve idea would shine... it would be really thin...

  • Why not add another tee at the bottom, no bubble plate. Rotate it 90 degrees to the sight glasses. Reduce it down to 2 or 3, add a 90' pointing upwards. At the top, at the condenser pipe, add a tee, pointing downwards. Add a valve under the tee. Only problem is going to be welding a custom spool between the bottom 90 and the top tee/valve.

    Open the valve, the vapor should bypass the plates. If not, you can potentially change that top tee to a 3 way valve at some expense.

    Now you've got a fancy SD hybrid still. Only real issue here is that this won't work using off-the-shelf, you'll need to weld at least 1 custom length spool, if not 2.

  • edited May 2014

    Hopefully this attachment works - here would be the variant with a 3 way valve.

    If the still used a single large bubble cap, you could presumably make a cap lift that would serve as a bypass, but that would be significantly more complicated.

    image

    Screen Shot 2014-05-04 at 11.32.55 AM.png
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  • Am I being too simplistic here? - Beside my 8" column is a 2" port (usually blanked off). If I was to blank off the top of the column and use a length of 2" pipe leading to the product condenser, I have in effect a pot still. The vapour will take the line of least resistance and not try to get up the blanked off column wouldn't it? I'm thinking of doing this for my stripping runs. I can't see why it wouldn't work. Surely it would only be a small amount of vapor that would try to go up the column and that would presumably condense and drop back down anyway as it's exit is blocked???

  • Here's one question, without a valve at the bottom and with the valve closed at the top -- would ethanol vapor be "trapped" there and not be recovered as it wouldn't come out until the still cooled down?

  • edited May 2014

    I was thinking the same thing for myself Grip. A 4"butterfly valve would be a neat addition under the Crystal Dragon for me. I'd need to fashion an alfoil pressure relief on the other spare 2" port in case of a drunken blonde moment though.

    Will have to question the boss over valve prices i think. It would also stop my lenses getting fogged up when i'm using the boiler to heat water for beer.

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    punkinscrystaldragonpotstillmod1.jpg
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  • On these plated columns do you need to do this at all?

    If you run these with no dephlegmator cooling at all (right from the start) do you not just get vapour heating the plates and blowing straight through?

    Ok there might be a slight vapour restriction but probably not enough to matter.

    Punkin do you still get fogging when blasting steam through the column?

    You probably only need 1 valve at the top of the bypass. If that is shut then the one under the column is obsolete. When the top valve is open you may find the column itself acts as a valve (vapour lock on 1st plate) so the preferential path is up the bypass.

  • You might be right @Myles and draining the dephlegmator could be better yet.

  • Going to depend on the amount of passive reflux (which is admittedly probably very small).

    The vapor speed through the bypass will be faster than through the column, which should offer less opportunity for passive reflux, even at the same height. Column will also have more overall surface area for condensation.

    For taller columns, I suspect that the bypass can offer a shorter distance to the condenser. In the diagram above I ran straight up, but if you condenser was closer to ground level, you might even be able to run a straight shot horizontally across (which has the added benefit of stabilizing your piping somewhat). Even less passive reflux.

    The most practical benefit would probably be cleaning. If for some reason you wanted to do a fast and dirty strip, you wouldn't necessarily be fouling the column with oily tails.

  • My lenses are all dirty and the Crystal Dragon needs pulling down and cleaning up before i use it again snce i did a strip run through it. There was no puking, but obviously some wash was carried along with the extra vapour speed.

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  • I was wondering why no one mentioned that to Myles, ive run my 4" many times with no coolent and I get some natural reflux, very minimal though, comes out around 75-80abv. And the harder I run it, like a strip run I get alot more natural reflux. Dunno why.

  • @googe said: I was wondering why no one mentioned that to Myles, ive run my 4" many times with no coolent and I get some natural reflux, very minimal though, comes out around 75-80abv. And the harder I run it, like a strip run I get alot more natural reflux. Dunno why.

    Probably because you are putting more vapor into suspension?

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  • So the general consensus seems to be that if you really want to run your plated column like a basic pot still then you need to disable or bypass the plates.

    Bearing in mind that you seem to get some natural reflux regardless, then perhaps all you need is a single gate valve between the top of the bypass and the product condenser.

    If you have any plates active most of the vapour should go through the bypass as it is the easier route.

  • You'd also need one to bypass the bypass when you wanted to use the paltes.

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  • :)) if you close the valve in the bypass line, then the vapour has to go through the plates.

    Open the valve and the vapour will mostly go up the bypass - possibly no vapour will make it through the plates - dependent on the plates.

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  • @Myles said: :)) if you close the valve in the bypass line, then the vapour has to go through the plates.

    Open the valve and the vapour will mostly go up the bypass - possibly no vapour will make it through the plates - dependent on the plates.

    image

    I would really like to know for certain how a config like this will behave as more pro guys are considering mounting our gin head directly to their boilers in conjunction with their columns.

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  • @Smaug said: I would really like to know for certain how a config like this will behave as more pro guys are considering mounting our gin head directly to their boilers in conjunction with their columns.

    The GB4 should not mount directly to a SD bubble column.

    It should be attached to a dedicated boiler that takes neutral as feedstock and make gin.
    Of course we are modular and more flexible than that, so darn near anything goes and is possible - but great gin should start from great neutral. Just my 2 cents.

  • edited May 2014

    Yes Lloyd, That is the recommendation we all try to communicate. But I can tell you that our recommendation does not always stick based on any number of variables within the end user's floor space. I always try and recommend a dedicated gin system. Some pro end users simply dred tearing down their columns to reconfig for the gin head.

    The end result is that some want to plop the gin head onto the top of their existing column inspite of our recommendation. Even if it means working off of a 10-12 foot ladder......crazy....

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  • Hmmm... what about replacing the CD gaskets with a stainless ring of an H cross section, and in the crossbar of the H, which you make about 8mm thick, you can machine a 4-5mm hole and have a bell-crank rod that goes in and raises and lowers a bypass valve/cone out of a hole... and maybe another bell crank to raise and lower the downcomer...

  • edited May 2014

    We need bubble plate tees with more TC ferrules! One for the vapor bypass, one for the cip ball, and a third for the lighting! Of course, you'd probably only be able to pull this off on the 8" column... or the 12" column... (Yes, I realize this would be a 6-way tee)

    My tig welding is too ugly to attempt to pull this off without ruining a ton of stainless.

  • if you bypass the vapor external to the column, you will likely add way more reflux than you realize....

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