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There are many valves out there people use to control the flow of vapor in their VM stills. I have tested most of them at a novice distiller level and have some questions/thoughts I wanted to bounce off some more experienced members who have maybe drawn different conclusions than myself. For the sake of this discussion I argue that against common belief, butterfly valves are the best valve for a beginner VM setup. After testing other valves such as Ball Valves, Gate Valves, and diaphragm valves, it seems as though the only one that does not have some sort of cavity/well that can collect condensed vapor and smear your run is the butterfly valve. Actuating a butterfly valve at any % opening does not create any pockets that turbulent vapor can passively reflux and create a pool within the distillation path, and with a fine enough control handle you can become very accurate with % opening to achieve your desired reflux ratio. See below images for where I have experienced condensate pooling. Keep in mind for all of my testing there was no affordable way for me to cleanly insulate the valve body itself, but only the piping before and after the valve. With perfect insulation the pooling liquid may vaporize again but for most novice distillers, perfect insulation will not be done for either lack of understanding, or lack of tools to do it properly. Please share if you agree, disagree, have seen other results, or have fixed the above issues with any of the valves I've listed. All valve image sections are shown in an open position.

Hang the gate valve upside down..
Tōtō

See below images for where I have experienced condensate pooling.

How have you "experienced" condensate pooling exactly? Did you instantly remove the valve mid-operation and tip it?

Tōtōchtin wrote: ↑Mon Jun 17, 2024 9:34 am Hang the gate valve upside down..
Tōtō

My thought was if I flip the gate valve upside down it would allow for the chamber where the gate retracts to act as an even larger pool. See below for what i mean.

Salt Must Flow wrote: ↑Mon Jun 17, 2024 9:56 am

See below images for where I have experienced condensate pooling.

How have you "experienced" condensate pooling exactly? Did you instantly remove the valve mid-operation and tip it?

Yes exactly. All of my valves are on tri clamp and to test each I ran my column in full reflux for 1 hour and then for 20 min ran @ a reflux ratio of 3. I then switch back to full reflux, detached valve, cap opening, dump valve into bowl. The margin of error could be that it would take me about 45 seconds from switching to full reflux, to dumping condensate into bowl, but with the oven mitts i dont really think I cooled down the valve enough to produce as much condensate as was pouring out.

A full port ball valve with a vertical stem has a very tiny volume for smearing relative to the mass flow rates.

A v-port or reduced port ball valve I believe would have even less.

It is common in industry to install gate and globe valves with a horizontal stem to prevent pooling in piping designed to accommodate two phase flow.

zach wrote: ↑Mon Jun 17, 2024 10:06 am A full port ball valve with a vertical stem has a very tiny volume for smearing relative to the mass flow rates.

A v-port or reduced port ball valve I believe would have even less.

It is common in industry to install gate and globe valves with a horizontal stem to prevent pooling in piping designed to accommodate two phase flow.

Cool, ill look into those options. Do you have any thoughts on the butterfly valve and if it will act in the way I am imagining it would? (Little to no smearing potential)

I can accept the small volume of *potential* pooling in my gate valve in exchange for the fine control it offers. It's that absurdly fine control that made me jump from CCVM to VM.

A butterfly valve can't be dialed-in like a gate valve.

Yeah I'm not concerned at all with 'potential pooling'. People used to say that shotgun condensers MUST be oriented vertical otherwise pooling will occur too. It's a non-issue. My gate valve is oriented perpendicular to the column and I would never install any valve parallel to the column because that would accumulate pooling during equalization which would all dump out the moment you opened the valve. Even though that is an insignificant amount of product, I just wouldn't do it because it would annoy me too much.

Salt Must Flow wrote: ↑Mon Jun 17, 2024 11:25 am Yeah I'm not concerned at all with 'potential pooling'. People used to say that shotgun condensers MUST be oriented vertical otherwise pooling will occur too. It's a non-issue. My gate valve is oriented perpendicular to the column and I would never install any valve parallel to the column because that would accumulate pooling during equalization which would all dump out the moment you opened the valve. Even though that is an insignificant amount of product, I just wouldn't do it because it would annoy me too much.

All of my testing has the valve perpendicular to the column as well. I agree the pooling is mostly insignificant to the overall product, but my goal was to find the valve type that reduces the pooling as much as possible regardless of other factors that the valve may introduce, i.e butterfly valve gives you less reflux control. BUT, does the butterfly valve offer the least amount of pooled product. So far my favorite has also been the gate valve for the control it offers, but I'm always open to improvements if there are improvements to be had.

ExperiencedNovice wrote: ↑Mon Jun 17, 2024 11:59 am

Salt Must Flow wrote: ↑Mon Jun 17, 2024 11:25 am Yeah I'm not concerned at all with 'potential pooling'. People used to say that shotgun condensers MUST be oriented vertical otherwise pooling will occur too. It's a non-issue. My gate valve is oriented perpendicular to the column and I would never install any valve parallel to the column because that would accumulate pooling during equalization which would all dump out the moment you opened the valve. Even though that is an insignificant amount of product, I just wouldn't do it because it would annoy me too much.

All of my testing has the valve perpendicular to the column as well. I agree the pooling is mostly insignificant to the overall product, but my goal was to find the valve type that reduces the pooling as much as possible regardless of other factors that the valve may introduce, i.e butterfly valve gives you less reflux control. BUT, does the butterfly valve offer the least amount of pooled product. So far my favorite has also been the gate valve for the control it offers, but I'm always open to improvements if there are improvements to be had.

Gate valve for the win in my opinion. As you said, for control, simplicity and convenience. Even if someone designed a new style of gate valve (or any style of valve) that alleged to not pool, I wouldn't replace the one I currently have because any potential difference would be so minuscule that it wouldn't make it on my 'to do' list. It just isn't something to be concerned about, at least in my opinion.

Just for fun I opened my 1" gate valve, set it level, flooded the valve with water and let any excess run out. I collected what poured out and it measured 2-1/4 ml. So assuming it pools, that's the most I could expect to accumulate.

ExperiencedNovice wrote: ↑Mon Jun 17, 2024 10:13 am
Cool, ill look into those options. Do you have any thoughts on the butterfly valve and if it will act in the way I am imagining it would? (Little to no smearing potential)

Not sure that it makes any difference. I think a butterfly could be slightly better for reduced pooling but less controllable for a fine adjustment.

ExperiencedNovice wrote: ↑Mon Jun 17, 2024 9:59 am

Tōtōchtin wrote: ↑Mon Jun 17, 2024 9:34 am Hang the gate valve upside down..
Tōtō

My thought was if I flip the gate valve upside down it would allow for the chamber where the gate retracts to act as an even larger pool. See below for what i mean.

Gate Valve Comparison.JPG

You were right about holding more upside down. I too pulled out a valve, my big 2" gate valve filled the well up and it only held 4.5 ml. A 2" ball valve set at 1/3 opening held 10 mls.
Tōtō

If you want to avoid pooling.
Build a rotating Valve VM, with a gate hanging down from one side of the reflux condenser.
The RC can be rotated causing the gate to cover the outlet.

shadylane wrote: ↑Mon Jun 17, 2024 3:37 pm If you want to avoid pooling.
Build a rotating Valve VM, with a gate hanging down from one side of the reflux condenser.
The RC can be rotated causing the gate to cover the outlet.

+1 shady …… and cheaper . But it won’t suit kitset builders that want off the shelf stuff without a bit of DIY modification .

Here is a relavent topic .
viewtopic.php?t=73239

I did do a little experimenting to see how far I could push the whole “Butterfly Valves don’t have fine enough adjustment for a VM” premise.

Used two valves with modified seals, interlocked with a turnbuckle.


Managed to get the fine adjustment I was after, but quickly realised my RC didn’t have the grunt to trial it properly

Should be noted that a typical butterfly has a raised seat, so I’m not sure that the no pooling argument really stacks up.

Another +1 on the rotary gate idea, albeit way beyond my pathetic fabrication skills

GrumbleStill wrote: ↑Mon Jun 17, 2024 10:48 pm I did do a little experimenting to see how far I could push the whole “Butterfly Valves don’t have fine enough adjustment for a VM” premise.

Used two valves with modified seals, interlocked with a turnbuckle.

IMG_2679.jpeg

Managed to get the fine adjustment I was after, but quickly realised my RC didn’t have the grunt to trial it properly

Should be noted that a typical butterfly has a raised seat, so I’m not sure that the no pooling argument really stacks up.

Another +1 on the rotary gate idea, albeit way beyond my pathetic fabrication skills

Grumble , that is clever AF . Looks like you can gi from VM to Pot mode .

GrumbleStill wrote: ↑Mon Jun 17, 2024 10:48 pm I did do a little experimenting to see how far I could push the whole “Butterfly Valves don’t have fine enough adjustment for a VM” premise.

Used two valves with modified seals, interlocked with a turnbuckle.

IMG_2679.jpeg

Managed to get the fine adjustment I was after, but quickly realised my RC didn’t have the grunt to trial it properly

Should be noted that a typical butterfly has a raised seat, so I’m not sure that the no pooling argument really stacks up.

Another +1 on the rotary gate idea, albeit way beyond my pathetic fabrication skills

I downloaded a cutsheet for the butterfly valve I was going to buy, and I see that "seat" you mentioned. In all of the pictures I didnt notice this and the premise I had been running on was that it is a smooth pathway with no seats, valleys, bends, or divets for condensate to pool in. With that not being the case ill probably just stick to gate valve without trying to test the butterfly valve myself. Thanks for the input everyone.

I very very much doubt that pooling product (of the amount we are talking) would make any difference to the run.(only 2 verys but I think its even more).
I have just been through all this and settled on a gate valve, ideally I would have liked a square gate but have not found one (which makes sense in most applications). The available adjustment on a gate valve was the deciding factor and quite frankly IMHO butterflies are a pain in the ass.

airhill wrote: ↑Wed Dec 18, 2024 10:22 pm I very very much doubt that pooling product (of the amount we are talking) would make any difference to the run.

I agree Airhill.
In the big picture, maybe a tiny amount, but there's many more variables that stack up and count more.

Actually Shady I was trying to be polite with the very very, it should have been F.A.

Good to see an old face back Airhill , from memory you have a lot of reflux column experience.
Last post 2012.

Everyone was going copper porn with flutes and bubblecaps and even the potstillers were getting uppity so I designed the ideal column and stopped posting.
Now I'm wanting to run faster (older and more impatient) so its going to be a 3" VM.

Really don't get the stress about pooling, which seems to be a "most clever boy in class" issue around here. After a run, dismount every component of your still above a bucket. Measure amount in bucket. Measure retained hearts amount. Divide first number by second. What was the percentage? I rest my case..

I think there's homemade VM valve builds that haven't been explored.

All that's needed something keeping the majority of the vapor from exiting to the product condenser.
It needs to be adjustable and the means of adjustment can't leak vapor to outside the stillhead.
Everyone uses commercially available valves rated for high pressure that are designed to close off 100%
The valves are big, heavy and expensive
Here's a thought for a DIY option. Kinda looks like a stove damper.

Although that would be relatively easy to do it does not really address the ? problem of all butterflies ( and ball valves), you have 1/4 of a turn from full open to full closed, with a gate valve you have ? about 10 full turns. Even gates are not linear but at least give more control.

Northsouth I have no idea what you are talking about

Stainless steel gate valves are not big, heavy and are not expensive.

I have a 1" gate valve for a 3" VM with two Tri-Clamp ferrules welded to it and it weighs less than 2 lbs. That means the valve alone weighs even less.
The valve is 5" tall and only 2-1/2" wide.
It only cost me $20 free shipping.


I also have a 1-1/2" gate valve for a 4" VM with two Tri-Clamp ferrules welded to it as well as a thermowell and it weighs less than 3 lbs. That means the valve alone weighs even less.
The valve is 6-1/2" tall and only 2-1/2" wide.
It only cost me $33 free shipping.


How big is too big? Big compared to what? How heavy is too heavy? Heavy compared to what? What price is expensive? Expensive compared to what? Gate valves are ideal and basically the standard because they are readily available, affordable, extremely high quality, extremely durable, incredibly adjustable and absolutely repeatable. These critiques of gate valves are commonly repeated over and over, but with nothing to back them up.