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After a great deal of thought, I am almost certain @ViolentBlue is correct about the condenser being the source of the problem.. Ever piece of the puzzle fits perfectly. 

I've read in other posts about very cold water causing surging, but it all kinda went over my head, as many other ideas were also being talked about at the same time. I think i finally get it now though.

The massive cloud of heated vapor hits my over-sized condenser, which due to it being a somewhat simple and inefficient design, I am running too much cooling water to. The vapor quickly shrinks down to a small quantity of liquid, creating a vacuum that sucks the vapor out of the column and a the same time lowers the boiling temperature, making the surging even worse. That continues until the surging vapor heats up the condenser enough that everything equalizes, and then the whole cycle starts again.

Feel free to correct me if I am wrong. Can't thank everyone enough for all the feedback, fairly certain I can get things dialed in for the next run. Hopefully this helps some else out down the road as well.

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You can verify this during the next run by holding a sheet of paper over your burp tube to see if a vacuum is being developed at any stage.

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20 hours ago, ViolentBlue said:

Hi Adam

the surging you are experiencing I think may be caused by the condenser. the style of condenser you have needs a fairly high flow rate to cool properly, so you are most likely having very cold water hitting very hot vapor, this will create a vacuum/pressure cycle that while similar to "chuffing" has a much longer cycle time

as for solutions,turn down your water flow to the condenser till it stops, your distillate will probably come out hot if left like this, but turn the cooling water up slowly till you find a point of equilibrium between surging and warm distillate. On a larger system suffering from this same issue, a vacuum break can be added to the top of condenser.

one other more costly option would be to swap out your condenser for a more efficient inverted flow multi tube condenser, if you are not recirculating your cooling water, this will save you a lot of water down the drain.

Steve,

That could be the problem if the condenser does not have enough tubes in it and if there is not a diffuser plate assembly above the intake tubes of the condenser.  We have never experience that issue with the condensers that we build here.  In case you don't know, my diffuser plate assembly slows down the vapor velocity so that the vapor spends more time in the tubes and my defuser plate assembly also spreads the vapor out so that it goes through the tubes evenly.  My defuser plate assembly also maximizes copper vapor interaction.

  Adam,

If what Steve suggested solves the problem let me know and I will sell you a defuser plate assembly for $49.55.  My defuser plate assembly will also make your condenser more efficient so that it does not use as much water.  It will also maximize your copper vapor interaction.

 

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3 hours ago, Southernhighlander said:

Steve,

That could be the problem if the condenser does not have enough tubes in it and if there is not a diffuser plate assembly above the intake tubes of the condenser.  We have never experience that issue with the condensers that we build here.  In case you don't know, my diffuser plate assembly slows down the vapor velocity so that the vapor spends more time in the tubes and my defuser plate assembly also spreads the vapor out so that it goes through the tubes evenly.  My defuser plate assembly also maximizes copper vapor interaction

I know what you are referring to, a diffuser plate will help a little with problem, and increase slightly the cooling capability of the condenser, slowing the water as I suggested in combination with a diffuser of some sort will reduce the symptoms, but not eliminate them completely. so its a good upgrade from current, but not a complete solution.

drop me a line, I have a couple more suggestions that are inexpensive to implement that will make your condenser even more efficient.

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3 hours ago, ViolentBlue said:

I know what you are referring to, a diffuser plate will help a little with problem, and increase slightly the cooling capability of the condenser, slowing the water as I suggested in combination with a diffuser of some sort will reduce the symptoms, but not eliminate them completely. so its a good upgrade from current, but not a complete solution.

drop me a line, I have a couple more suggestions that are inexpensive to implement that will make your condenser even more efficient.

The condensers on my stills work just fine with no surging issues and they all have diffusers.  I have over 4,000 stills out there that prove that, with a little less than 300 of those in distilleries.  In fact my pro series steam fired stripping stills are some of the fastest out there with stripping run times as short as 3 hours from the time that the still is turned on.  I only sold Adam his pot.  I did not sell him the column and condenser or the heating system.  Just wanted to make sure that everyone is aware. 

Also, we gained over over 76% more efficiency in our 12"x36" tube side condenser when we added my diffuser plate assembly.  That is a heck of a lot more than a little.  I am not referencing a single plate either, there is a lot more to my diffuser plate assemblies than that.  The 12" condenser that I am referencing had a 2" line arm and no splitter, before we added my device.  

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My German stills have Danforth temperature controlled water valves of the condensors.  This because condenser  water temperature has a significant effect on the complete operation.  I don't know if your still has condensor temp control, but it may solve your problem.  

To test it, just do as previously suggested and minimize your cooling water until your distillate is coming out warm to the touch. Lock your water flow to maintain a constant temp and see if the problem goes away.  

DO NOT walk away from your still when you are screwing around with condenser cooling !  

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55 minutes ago, Roger said:

My German stills have Danforth temperature controlled water valves of the condensors.  This because condenser  water temperature has a significant effect on the complete operation.  I don't know if your still has condenser temp control, but it may solve your problem.  

 

Roger is exactly right and he brings up a very good point.  The thermostatic valves that he is referencing can really take a load off when it comes to cooling control. We supply Danfoss valves as an option on all of our vodka stills and we have had some customer use them on our 4 plates stills as well.  One Danfoss valve will give you automated control over both your final condenser and dephlegmator using our design.  Since they are a thermostatic valves, they do not require a power source.  We are Danfoss vendors.  Adam if you want to go that route, just let me know and I will set you up.

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1 hour ago, Southernhighlander said:

Roger is exactly right and he brings up a very good point.  The thermostatic valves that he is referencing can really take a load off when it comes to cooling control. We supply Danfoss valves as an option on all of our vodka stills and we have had some customer use them on our 4 plates stills as well.  One Danfoss valve will give you automated control over both your final condenser and dephlegmator using our design.  Since they are a thermostatic valves, they do not require a power source.  We are Danfoss vendors.  Adam if you want to go that route, just let me know and I will set you up.

We have tried this with our vodka still (which has a boiler and elements from @Southernhighlander) and Danfoss valves, and haven't been able to make it work. We might get in touch with you soon Paul to see if you can help us give it another go...

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Hi Bluestar,

 

Holler at me on my email and we will get it lined out for you. paul@distillery-equipment.com

Thank you.

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When attempting to use a Danforth valve on a Vodka column be aware that they come in two basic styles. One is a complete closure, and the second is with a small constant flow hole which always allows some water through, even when completely closed. I think the idea is that the small hole type will always allow some water flow, and not permit a condenser to run "dry" by too tight of a setting. That's fine for a condenser, but it is problematic with a defleg because even the "small" amount that is constantly flowing , may be more that you need (depending on water temp) and will huff the vodka in the top of the defleg. If your condenser huffs even with a water control valve completely shut, check to see if it has some constant minimum rate and if so you can reduce that with an in-line (pre Danforth valve)1955507288_danforthcolumn.thumb.jpg.5ad82951710c329fd464a66685b694ae.jpg needle valve.

It took a lot to win 2 gold medals with our Vodka made from Grapes, but we did it with one of Paul's columns !   There truly is a life outside of Re-bubbled NGS.  !

danforth condensers.jpg

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Roger, our Danfoss valves are reverse acting proportional control.  The orifice opens wider when more coolant is needed and closes more when less coolant is needed but it never closes all of the way with our plumbing method. 

  When we first started testing them, we used one for each dephlegmator and one for the final condenser.  That did not work well at all for the dephlegmators, as they had wild temp swings at the dephlegmator.  Then we tried using one Danfoss for both the final condenser and the dephlegmator with a very different plumbing method and it worked pretty good on the really big still that we first tried it on but there was still a little surging, however later on we found that on some of the smaller stills and even a couple of big ones that customers were using, the temp swings were still occuring, making it impossible for the still to run correctly.  Finally, through a huge amount of trial and error we  got it right.  We can use one danfoss for the final condenser and dephlegmator and it works great, and those stills are all now running great, except that maybe we missed Blue Star. As soon as I get a chance I will send you the plumbing design and some video of it in operation.  The flow is nice and steady.

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Paul - The Danfoss on my German stills do exactly as you say, they feed the coolant into the bottom of the condensers where it then flows upward. The side by side  Danfoss valves in my pic release water into the bottom of the condensers based on demand as sensed by the "warmed" water at the top of the condenser. It then flows that "warmer water" into the deflegs on top of my Hybrid pots.   So note that not only is it controlled, but it is also "warm" and as such does not shock the defleg, which can aggravate a Huff. 

I can't run it that way into my column, because I am using the warmed condenser water in my pot deflegs, and by then the output is too hot to also sufficiently cool the column defleg. As such we needle valved cold into the column top Danfoss.

 

 

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4 hours ago, Roger said:

Paul - The Danfoss on my German stills do exactly as you say, they feed the coolant into the bottom of the condensers where it then flows upward. The side by side  Danfoss valves in my pic release water into the bottom of the condensers based on demand as sensed by the "warmed" water at the top of the condenser. It then flows that "warmer water" into the deflegs on top of my Hybrid pots.   So note that not only is it controlled, but it is also "warm" and as such does not shock the defleg, which can aggravate a Huff. 

I can't run it that way into my column, because I am using the warmed condenser water in my pot deflegs, and by then the output is too hot to also sufficiently cool the column defleg. As such we needle valved cold into the column top Danfoss.

 

 

Yep, my Danfoss valves are on the input side of the final condenser with the temp probe at the output of the final condenser.  The water from the output of the condenser goes into the dephlegmator at the higher temp and everything works great with a nice steady output.  We have bypasses set up pretty much like yours are as well.

Another good thing to have are 2 different manual steam valves, one for fine control and the other for course control.  You can dial the steam in just where you want it.  This kind of heat and cooling control keeps things nice and simple which is the way that I like it.  I'm not saying that there is anything wrong with computer automation, I just like old school simplicity a lot better.  

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Just in case someone cares, or reads this down the line, after a few runs, I'm pretty sure the surging was due to the condenser. I made some changes to it to make it more efficient, tweaked some settings, and was more careful with how much cooling water i was sending to the PC. Thanks so much to everyone that took the time to throw some ideas my way.

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