Concentric LM, add VM?

[Gatsby]

It seems that the Concentric LM is a super configuration, able to run in pot or LM modes or anything in between. Since all of my present build is modular it would be simple to add a tee below the concentric head, a valve, and product condenser, thereby creating a VM.
But what would I be gaining? What advantage would such a setup have?
Gatsby

[StillerBoy]

From what I'm reading in your post, you are not presently running a concentric.. would that be a correct assumption..

As a person who use a concentric as my main setup, I'm of the view that you can not turn a concentric setup into a vapour unit.. I could be wrong, butttt, it could be possible if the vapour throat body was not used..

I have used the reflux condenser style on a VM setup, but it is setup on a tee with two valves..

Mars

[still_stirrin]

I have a combination LM/VM with a concentric reflux condenser.

The LM cup is an annular cup, that is a 1” pipe inside a 1-1/2” concentric inner tube, which give me a 1/4” annular cup around the 1” throat. The height of the cup (about 1-1/2”) is the liquid collection which when full, spills back over the throat tube back down the column.

The water jacket on the reflux condenser is 1/4” wide...a 2” pipe over the 1-1/2” inner pipe, which also makes the outer wall of the liquid collection cup. The water jacket has a spiral of copper inside so the coolant will swirl as it passes through the reflux condenser’s water jacket. It is very efficient. To help increase the vapor conduction to the condenser’s inner wall, I have some copper scrubbies stuffed in the concentric..but it is placed higher than the liquid cup’s inner pipe/weir.

I have needle valve on a 3/8” outlet port. This is the LM (control) valve. I usually stabilize the reflux before opening the LM valve. And then, I open it just enough to produce a very small stream. With the heat high enough to maintain reflux, the liquid level in the annular cup will stay full and spilling back down the column. This keeps the purity high with a high reflux ratio.

Now, the VM valve, a 1” ball valve (you could use a gate valve too) plumbed to the branch line of a 2” x 1-1/2” DWV Tee. It is position right below the LM head where the 1” vapor tube (throat) is located. So, when the VM valve is opened, the vapor is divided between the concentric reflux condenser (and the liquid cup/throat) and the branch line which feeds the VM valve. Once the VM valve is set, the vapor will always be proportionally divided the same regardless of the coolant flow or the heat input. This is the advantage of the vapor managed reflux system. It self regulates to keep the purity constant.

When the run nears the tails, the VM product will rapidly diminish and quite. That’s when I close it and once again use the LM outlet to finish drawing off the tails.

But, my reflux head (the combo LM/VM) mounts to the 2” column with a tri-clamp joint. So, when I do stripping runs, I have a separate potstill head and a short 12” riser that replaces the reflux head and 39” tall column. It is a simple potstill head...a 90* elbow with a union which mates with the product condenser, a 24” long shotgun condenser...the same condenser I use to connect to the VM outlet.

The secret is to have the right tools to do what you’re trying to do. Build a simple potstill head for stripping and potstill spirit runs. And then build a reflux head for your high purity neutrals.

And the concentric LM/VM head is an excellent tool because of its versatility. The LM is the best for compressing the foreshots and early heads. The VM is best for product of the hearts section because it will push the tails to the very end. And the potstill works perfectly as intended for stripping.

I have a few threads where I’ve detailed the combo head and how it functions. Search for it if you need more explanation.

In conclusion, both the LM and the VM are easier to operate than the CM, because reflux is not sensitive to coolant flow rates or water temperatures. And the VM is far and away the easiest to run because of the stability of the purity throughout the run.
ss

p.s. - I apologize for such a loooong post. But I wanted you to understand my setup and the operation.

[Gatsby]

So, I guess the answer to my question is the "self regulating" feature of VM; cool.
I have the same head configuration as yours SS, and I do happen to have a 2 x 1-1/2 x 2 Tee so I'll pursue that, thanks.
About the Ball valve: My memory is that the ball rides in a seal, (rather than against metal). Do you know what that seal is made from, is it a special valve or just one off the shelf?
If you were going for a lightly flavored product, (light rum), roughly how far should the valve be open?

[still_stirrin]

About the Ball valve: My memory is that the ball rides in a seal, (rather than against metal). Do you know what that seal is made from, is it a special valve or just one off the shelf?

The valve I bought at “the big box store” has a stainless steel ball and stem and uses a teflon seat and seal in the valve. I put the valve shaft in the horizontal orientation so when cracked open the opening is on the bottom and top of the vapor pipe. This way, any condensate that may form (not likely however) will not “puddle” in the pipe.

If you were going for a lightly flavored product, (light rum), roughly how far should the valve be open?

As I noted above, my valve has the stem horizontal so that the valve handle point towards the product condenser when fully opened. For most reflux runs, I keep the valve roughly pointing towards 5 o’clock or 4:30 a little more open. This will keep the reflux ratio up to at least 10:1, or even higher.

For a rum, I would try to get the product purity up to 155-160 proof. It is higher than what you’d need for a barrel aged rum. But, it makes a very nice white “151 rum”.

But, I always strip my rum ferments using the potstill head. So, that will get me the low wines at 25-30% ABV. You could even run it a little lower too if you want to increase the flavor. A lot of the “buttery” flavors come over late in the run, so run it as you desire.
ss