Ways to narrow the take-off port

[Iulistoi]

Hi, I want to reduce the diameter of the take-off port in my CCVM column. Now, the T is equal and the default RR is 1:1. If I would reduce the cross sectional area of the take-off port to 1/4 of the column, theoreticaly, I would have a 4:1 minimum RR.

I don't want to change the T because I soldered it. Another reason is I don't find a T with smaller takeoff. My thought was to solder a ring within the hole to narrow the path, or something like a funel or by creating some turbulences through the PC.

Once I used a corrugated SS hose to the PC and the minimum RR was 3:1 due to turbulences, prety good for 95%. But then I had SS scrubber packing. Now I use SPP.

I hate very fine adjusting the heigh of the RC and I never use 1:1 RR. Tails are very few and nasty and it's not worth it to waste time, energy and water to fill the column with stinky vapours.

[Chauncey]

I'd chop it and solder in some tc ferrules w a reducer

[cob]

Make a sleeve insert the same length as your takeoff diameter.

Slide it in and cover as much or as little opening as you need.

[kimbodious]

Put a valve after the offtake and operate it as a VM and leave the RC in the one position

[Yummyrum]

Put a valve after the offtake and operate it as a VM and leave the RC in the one position

My thoughts too Kimbo

[Iulistoi]

Are you sure the ball valves doesn't have nasty alloys that dissolve in high alcohol concentration?

[Andrew_90]

You mean like this? 54mm to 22mm.

[Yummyrum]

You mean like this? 54mm to 22mm.

Whack a ball valve where that tri-clamp is and call it happy days

[Iulistoi]

You mean like this? 54mm to 22mm.

No, I didn't mean the reducer. There is still 1:1 RR. I mean the take off port. The hole that exits from the column has to be narrower than the column to achieve greater minimum reflux rate.

[Setsumi]

I allways thought on a CCVM your reflux ratio will reduce the lower the coil drops. My off takes are not equal diameter to the column but if i lower the coil my take off speed and volume reduces while the reflux return increase by the volume not taken. So my RR increase? Or that is how i understand CCVM.

Edit: i do not think you need that fine adjustment to the condenser but the suggestion to throttle the output with a valve would work to increase the RR. The vapour not passing the valve would get condensed increasing the RR.

[Demy]

I would rather "play" with the coil height rather than change the column ... I guess you discarded this option?

[shadylane]

I would rather "play" with the coil height rather than change the column ...

+1
I was thinking, modify the reflux coil to make it less sensitive.
Maybe have a cold finger on the bottom of the coiled RC.
Or have the bottom coils wound looser than the rest?

Might even find that reversing the cooling water flow to the RC will help.
That's the first thing I'd try before major column modifications.

[Twisted Brick]

I allways thought on a CCVM your reflux ratio will reduce the lower the coil drops. My off takes are not equal diameter to the column but if i lower the coil my take off speed and volume reduces while the reflux return increase by the volume not taken. So my RR increase? Or that is how i understand CCVM.

That's how I understand it to work. DAD300 explains it here (from another Forum)

re: Variable Reflux Condenser VM
by dad300 » Thu Oct 13, 2011 4:36 pm

Moving the coil up and down changes the origination point of the reflux. Making it either before or after the take-off port. Thus when lowered below the take-off port, it blocks the take-off of all vapor. That point I have already proven, like the Condenser Controlled Column Manu showed us.

With this setup, the reflux condenser also physically blocks some portion of the take-off port, So, the take-off port starts out at 3" dia. At full reflux it is functionally zero diameter. At minimal reflux it is again 3" diameter. In between it is infinitely adjustable.

The idea(s) here are to eliminate the valve and create a way to balance the reflux vs take-off. I have "kind of" proven that to myself. I did go from full reflux to 91% to 81%. That is why the first trial I limited the column height. If I had used 60" of column, I'd have had 95% ABV regardless of the condenser position. My 2" VM without a valve does that.

But the first distillation happened so fast, relatively speaking, that I didn't feel in control. Frankly, I was to amazed by the take-off rate.

Also, I seem to remember reading one of Dad300's posts here regarding anomalies in vapor collection (a semi-reduction) at the take-off port in a VM still that do not occur when configured as a CCVM, but can't locate the thread at the moment. He does however, discuss measuring reflux-ratio in a (3") VM still that has been stepped down after the take-off port, like Andrew_90's here:

3" VM Still - take-off port dimension/stepdown Questions

I would rather "play" with the coil height rather than change the column ...

+1
I was thinking, modify the reflux coil to make it less sensitive.
Maybe have a cold finger on the bottom of the coiled RC.
Or have the bottom coils wound looser than the rest?

Might even find that reversing the cooling water flow to the RC will help.
That's the first thing I'd try before major column modifications.

Here's some thoughts on doing just this:

the problem with the cc still

[Sporacle]

If I'm reading this right, it's a CCVM and the RC acts as the valve or the narrowing of the take off, or am I totally missing something, is it not as simple as lowering the RC to increase the reflux ratio and raise it to decrease it.
Find the combo of power, RC height and flow and take off rate that gives you around that 94 or 95, or as some have done detune it a bit.
I can't figure out what the reduction of diameter will acheive that won't be achieved by running it as it was intended

[shadylane]

If I'm reading this right, it's a CCVM and the RC acts as the valve or the narrowing of the take off, or am I totally missing something, is it not as simple as lowering the RC to increase the reflux ratio and raise it to decrease it.

That's the basic theory.
In practice it gets a little more complicated.
Even the Product Condenser has an effect on the reflux ratio.

[Sporacle]

That's my point Shady, why not just operate it as a CCVM, if you want a physical valve build a VM.
I've just started running my CCVM and it suits me, very basic and simple; like it's operator

[MihiT]

I haven't read through all the replies, but yeah, a condensate-management valve seems the simplest solution.

From an engineering stand point "Orifice plates" are used in steam/fluid distribution systems, so it's probably an effective method here too.

[Iulistoi]

The point is, I want to use just 2 positions of the reflux condenser coil: the lowest for total reflux and the highest for 4:1 reflux ratio, with no intermediate positions. I simply don't want lower reflux ratio.

[Setsumi]

The point is, I want to use just 2 positions of the reflux condenser coil: the lowest for total reflux and the highest for 4:1 reflux ratio, with no intermediate positions. I simply don't want lower reflux ratio.

Then a VM will work. As yummy said put a valve on it.

The vapour that does not go through the valve will return as reflux as long as it stays vapour before the valve in a VM setup. If it condenses before the valve in your product path it will smear into the product. Even if you reduce the take off diameter in CCVM you will still have to regulate the takeoff with coil position and i think you will find that it is not going to be just open or closed.

On one of my CCVM condensers that was i bit inefficient i soldered a shaped plate onto the coil to cover the take off orifice. When taking fores i could twist the coil to open the port.... it worked but only to a degree since vapour can pass through the smallest gap.

[Yummyrum]

I have not operated a CCVM , but in my mind , you put a smaller takeoff port on it , it will be even more titchy to adjust .

However , if you convert it to VM , a small takeoff port will allow much more smooth transition in the range you are hoping to operate it in .

Why ,If two positions is all you want , you could get all fancy . Use a three way valve that switches the vapour through two other valves , one for Foreshots , the other for hearts .

Or , you could try something like Demy or Andrew have done with their CCVMs . They have ways to adjust and hold coil at various heights with a scale to indicate exact position.

[Demy]

In my humble opinion you decide which to choose: VM or CCVM, it makes no sense to make a 2 things hybrid. CCVM was born precisely to replace the valve (it is the coil to function as a valve) and it works beautifully, I made a video on a simple adjustment mechanism .... But if you prefer a valve use that, keep in mind that a stainless steel valve Coarse costs a lot and weighs so much.

[Iulistoi]

This is how I adjust the position of the double coiled reflux condenser, but I am tired of stepping up and down on the ladder to move the coil up or down by 1 mm.

In the second picture is the position of the coil with which I am satisfied. In that position the RR is 4:1 and I can take 1.2 l/h at 96% abv with about 2000W heating power.

I want to keep the coil in the highest position and take 4:1 RR, not 1:1 as it is now.

I think to put some teflon tape on that hole to reduce the way the vapors go by a quarter. Do you think that teflon in hot alcohol vapour environment can leak nasty things?

[Sporacle]

I think your at the point of either converting to a VM or building something as Yummy suggested to adjust the RC from ground height

[Setsumi]

This is how I adjust the position of the double coiled reflux condenser, but I am tired of stepping up and down on the ladder to move the coil up or down by 1 mm.

In the second picture is the position of the coil with which I am satisfied. In that position the RR is 4:1 and I can take 1.2 l/h at 96% abv with about 2000W heating power.

I want to keep the coil in the highest position and take 4:1 RR, not 1:1 as it is now.

I think to put some teflon tape on that hole to reduce the way the vapors go by a quarter. Do you think that teflon in hot alcohol vapour environment can leak nasty things?

20210904_111430.jpg

20210906_005533.jpg

So the picture of the coil in the T is at 4:1 RR and you are happy with that setting? I understand the issue you have with getting on a ladder to do the adjustment. As said, Demmy and Andrew_90 has solutions to do the settings. Myself would get 45 deg elbows on the feed and outlets to position the coil for full reflux by default. Then when you need take off lift the coil once and stick a spoon into the coils to keep it raised in the 4:1 position or as close as the coils allows... then use power or energy management to take fores and heads at a lower speed and raise energy input for hearts...

You do not need to lift the coil to 1:1 RR if you do not want it.... but it seems i/we do not understand your problem?

Last, although RR do play a role in % ABV your column is the main work horse.

[shadylane]

I have not operated a CCVM , but in my mind , you put a smaller takeoff port on it , it will be even more titchy to adjust .

That's what I found, a smaller takeoff port wasn't the best answer.
It made the adjustments more twitchy and didn't effect the reflux ratio near as much as thought.
The last experiment had small piece of copper sheet soldered to the RC coil
Instead of raising the coil, it was rotated to open and close the port.
That was much easier to adjust. I could take a stick, reach up and wack the RC causing it to turn.

Guess it could be called VOCVM. Valve On Condenser Vapor Management.

[Saltbush Bill]

I could take a stick, reach up and wack the RC causing it to turn.

Love the scientific approach Shady
SWCM "Stick Wack Control Management"

[shadylane]

What ever gets the job done.
Wish, I'd taken some pictures to share.

[fzbwfk9r]

ShadyLane: using a piece of material to create a valve so you just rotate your coil....

how did that work?
Are you still using that method?