CCVM design feedback

[kimbodious]

. A smaller port at the offtake increases the reflux ratio thereby reducing the output rate.

Indeed , but when do we ever need it ?

When running in reflux mode , invariably it’s to make neutral and with such a high Reflux ratio that again port size is not an issue .

The issue I read here and other places is people’s complaints on how long spirit runs take and not enough time etc. A smaller port on the offtake slows down the rate of output if runtimes are an issue. It does however increase the reflux ratio for higher purity. But if you are already getting highest purity why then would you want to throttle the rate of output.

I’ll digress. My mate has a 2” diameter column on his CCVM but it only has a 0.5” offtake. He never has to move the RC because the reflux ratio is being set by the very small offtake. He has no trouble at all getting two drips a second at the highest purity BUT that is about as fast as his still runs!

[greggn]

here's what I have so far

Personally, I feel that motorizing the movement of the RC is needless over-engineering. As a retired engineer, I understand the desire to design and automate but sometimes some things are simple for a reason.

That said, if you're determined to put a motor on your RC keep in mind that you'll need to lift the weight of the RC and both its supply lines while full of water. Your planned RC appears significantly over-sized so your motor will need to move a lot of weight.

[MooseMan]

here's what I have so far

Personally, I feel that motorizing the movement of the RC is needless over-engineering. As a retired engineer, I understand the desire to design and automate but sometimes some things are simple for a reason.

That said, if you're determined to put a motor on your RC keep in mind that you'll need to lift the weight of the RC and both its supply lines while full of water. Your planned RC appears significantly over-sized so your motor will need to move a lot of weight.

Yeah Gregg I too think that the RC is well over engineered for the proposed amount of heat input, but hell, is there any such thing as "Too much" condensing capacity?

[StillCity]

here's what I have so far

Personally, I feel that motorizing the movement of the RC is needless over-engineering. As a retired engineer, I understand the desire to design and automate but sometimes some things are simple for a reason.

That said, if you're determined to put a motor on your RC keep in mind that you'll need to lift the weight of the RC and both its supply lines while full of water. Your planned RC appears significantly over-sized so your motor will need to move a lot of weight.

I already changed the design of my RC coil to a double helix of 3/8 OD, since it will be easier, cheaper, lighter, and allow a higher flow rate (since I running RC and PC in series, the flow rate may be critical).

I will calculate the mass the motor will need to move, (one benefit of CAD), and pick the lead of the screw and motor torque based on that.
EDIT: the total mass of the moving parts of the RC assembly, filled with water, will be around 2.25 kg. This will apply a ~2 N*cm torque on the lead screw I planned to use. The NEMA 17 stepper motor that comes with the kit is rated for 40-50 N*cm, so should be just fine.

The still will end up near 9 ft high, so forgetting automation, it will be nice to be able to jog the RC up and down without using a ladder.
And I still think controlling RC position to hold a constant reflux ratio could have some use, though I will need to gain some experience running manually to see if this makes sense.

[MooseMan]

That will be a lot easier to wind mate, I've done both a double helix (For my Dimroth) and a straight cold finger with a coil over the top (For the RC) both in 10mm.

As you'll be running much lower power in reflux, you will be fine with 2 coils for your RC.

If you have the kit and knowledge to easily motorise the coil movement I say go for it (I was a Toolmaker in a former life, so I understand) just because you can, but do it manually first to get your feels and, make sure you have a way to do it manually should your stepper fail.

I use a bent bit of flat copper slid between the coils to hold the RC in position in my column, and I have to move it 3 times during a 8-12hr run.

[StillCity]

I have a question about heating element control. I do not want to use a PID, but I do want to be able to set the wattage from an arduino or PLC.

For many dimmer applications such as lights, a TRIAC is used, since it works by cutting a portion of each AC oscillation, thus avoiding flickering. But this is more expensive and complex.
For a heating element, flickering is not an issue, so a normal solid-state relay could be used to cut power periodically and adjust the average wattage.

My question is: How sensitive will a 50l boiler be to cuts in power?
So say I want to run at 50% power, it could be on 1 sec > off 1 sec > on 1 sec etc. But longer intervals would be easier on the relay, maybe 10 seconds or so.

Would 10 sec on > 10 sec off affect the vapor flow or the balance of a reflux column?

Or for 20%, would 2 sec on > 8 sec off cause issues?

I just don't have enough experience to know the longest interval I could use before it causes uneven vapor flow. Does anyone have an intuition on this?

[Salt Must Flow]

I have a question about heating element control. I do not want to use a PID, but I do want to be able to set the wattage from an arduino or PLC.

For many dimmer applications such as lights, a TRIAC is used, since it works by cutting a portion of each AC oscillation, thus avoiding flickering. But this is more expensive and complex.
For a heating element, flickering is not an issue, so a normal solid-state relay could be used to cut power periodically and adjust the average wattage.

My question is: How sensitive will a 50l boiler be to cuts in power?
So say I want to run at 50% power, it could be on 1 sec > off 1 sec > on 1 sec etc. But longer intervals would be easier on the relay, maybe 10 seconds or so.

Would 10 sec on > 10 sec off affect the vapor flow or the balance of a reflux column?

Or for 20%, would 2 sec on > 8 sec off cause issues?

I just don't have enough experience to know the longest interval I could use before it causes uneven vapor flow. Does anyone have an intuition on this?

Check out the specs (maybe the instruction manual) for the Auber Insruments DSPR400 and see if you can replicate it's on/off pulse rate. I've been using the DSPR400 for quite a while and it works wonderfully. I can adjust it anywhere from 1%-100% on and it behaves smooth as can be.

The Auber DSPR400 has two modes. Distilling mode which is variable power 1%-100% and PID mode which is also very handy for many uses. You use a RTD sensor and the temp reads in 1/10th degree resolution which is also very handy. I just don't know of a better controller that exists today.

[shadylane]

I would plumb the inlets to your RC and PC from the same source in parallel not series, when operating in reflux mode the RC does all the heavy work.
Put a valve on either the inlet or outlet of the PC to regulate flow and ensure your RC gets maximum flow.

I agree parallel works better, the 2 condensers have different cooling flow requirements.

[tjsc5f]

I do not want to use a PID, but I do want to be able to set the wattage from an arduino or PLC.

I used a LSA-H3P90YB solid state voltage regulator. Works really well, no complaints.
Here's a thread where I talked about my setup and the app I created to control/monitor the still.
viewtopic.php?t=87572

[StillCity]

I used a LSA-H3P90YB solid state voltage regulator. Works really well, no complaints.
Here's a thread where I talked about my setup and the app I created to control/monitor the still.
viewtopic.php?t=87572

fascinating!

[PLAYMP]

My question is: How sensitive will a 50l boiler be to cuts in power?
So say I want to run at 50% power, it could be on 1 sec > off 1 sec > on 1 sec etc. But longer intervals would be easier on the relay, maybe 10 seconds or so.

Would 10 sec on > 10 sec off affect the vapor flow or the balance of a reflux column?

Or for 20%, would 2 sec on > 8 sec off cause issues?

Hopefully others smarter than me can chime in but I think most SSRs out of the box operate on 60 cycles per second. I run a 3” vm with a highly insulated column and boiler and I’d definitely notice an impact if I shut it down every few seconds.

I do second Salt Must Flow on the DSPR400. That thing runs smooth as butter.

[Yummyrum]

Stillcity , there are two common ways to control the power. One is time proportional , which is the method you suggested and the easiest to implement.
The other is burstfire control . Burstfire spreads the power cycles evenly over time so you are not getting a long on to off period .
So where as say, 75% power with time proportional would switch on element for 75 cycles and then off for 25cycles ,
Burst fire turns on for 3 and off for 1 so there is more smoother boiling .
And if you want 76% , it just adds an extra on cycle every 100.
77% adds two extra evenly spaced in cycles per hundred .
The math in the controller would be a little more complex ….. but you get the idea.

Interestingly the Auberin controllers mentioned have the option for both .

In reality I don’t think that having a 100 cycle period will make that much difference other than a quieter element. .Between the thermal mass and heat transfer delay through the element then into the liquid ,and having sufficient headspace in the boiler to buffer any residual modulated boil I can’t see any problems .

[MooseMan]

Between the thermal mass and heat transfer delay through the element then into the liquid ,and having sufficient headspace in the boiler to buffer any residual modulated boil I can’t see any problems .

What this man said ^

[StillCity]

To save on cost, I am hoping this takeoff design will work. 2.87" ID to 1.37" ID reducing tri-clamp Tee, then down to a 3/4 Liebig.
Is this takeoff too small? with the screw lead of 8mm and a 200-step motor, I can adjust the coil in vertical steps of about 1.5 thousands of an inch. (850 steps across the takeoff opening)

regarding the element adjustment, I may have to wait until I buy an element, hook it up with my controller, and experiment to see what works.

[Yummyrum]

Is this takeoff too small? with the screw lead of 8mm and a 200-step motor, I can adjust the coil in vertical steps of about 1.5 thousands of an inch. (850 steps across the takeoff opening

Probably not if you only intent to make Neutral .
Just by having those sizes , the still would be working as a VM with a Reflux ratio a little under 6:1 .So even without lowering the Reflux coil , it will already be making some pretty high avb stuff .

Its going to run a lot faster than the example Kimbodius sited with his mates setup which excuse my calculations but is closer to 15:1 and explains why he only gets drips .

Obviously , the bigger port you have the better , but I think in practice , the size you show will work and still give you enough control .

Unless of coarse , you might want to be detuning to make flavoured product , then you won’t be able to reduce the RR enough . Personally , I’d spend the extra bucks and go the full sized Tee and reduce down .

[Sporacle]

I'd go with the full size Tee as well, I feel it will allow for easier control of the valve (RC).
It will also give you a few more options in a modular sense down the track

[kimbodious]

@Stillcity, you won’t get such fine-scale control of reflux ratios by incremental movements of a regular RC coil. You might if say all the reflux occurred immediately at the bottom edge of the RC but a coil usually doesn’t work that way, some vapour will reach higher up. You’ll be able to feel where that vapour/RC interface is on the outside of the column.

My RC has three positions, all the way down, up just a fraction and all the way up. There’s about 10cm between the top and bottom positions. Up just a fraction is about 1cm up from the lowest position. The wonder of the CCVM is how quickly it responds to changes in RC position- brilliant gear!

If money more than time is an issue, consider a 2” system. A 2” system is plenty big enough for a pot still. I get up to 4 LPH on my pot still and 1.2 LPH at highest purity on my CCVM. I do one spirit run a year involving 40+ L of low wines. The spirit run takes forever, about 16 hours, but I end up with roughly 14L of highest purity neutral spirit - enough to last this household more than a year. I figure it it’s only once a year it’s a reasonable sacrifice.

[StillCity]

is this a better off-take?
3" tri-clamp to 3/4 copper tube was tricky with standard fittings, but I can weld, machine, and solder myself to a solution.

damn, this forum has some great giant's shoulders to stand on
thanks for the continued feedback!

[PLAYMP]

I think I missed the part of the thread where you abandoned the shotgun but my vm cleanly goes from 3”, and then a reducer to 2” into an AliExpress shotgun condenser and an extra 2” spool to bring the output closer to the ground. Not prohibitively expensive, gives you plenty of room to let your RC drive the reflux ratio, and saves you from soldering anything on your modular rig.

[Sporacle]

That design looks like it may cause some pooling due to the angle of the liebig.
Personally I would have the take-off vertical and reduced to 3/4 before angling the liebig away.
This should reduce any potential pooling points

Its hard to articulate, if it makes no sense let me know and I'll go down to the shed and take a photo

[MooseMan]

2023-08-07 22_06_27-CCVM still V2 _ full assembly.png
is this a better off-take?
3" tri-clamp to 3/4 copper tube was tricky with standard fittings, but I can weld, machine, and solder myself to a solution.

damn, this forum has some great giant's shoulders to stand on
thanks for the continued feedback!

Much better way to go.
But you can get SS 3" to 1" reducers that are not concentric, so if you can find one, that's your best bet. Tri AliExpress.
1" Tri clamp on the Liebig and you're sorted.

[kimbodious]

Search for triclamp reducer fittings and you’ll find gems like this one! This is a 2” to 3/4”. Then you get a triclamp ferrule to solder on to your leibig and you’re good to go! You’ll see where I used one on my CCVM to put a long spout from my shotgun PC.

[Wildcats]

Whatever direction you go.... Modular is the way to go. You can change it up at any time. I'm in the camp that the same diameter thru all the vapor path will make a better product. I know that a bold statement and I'll probably get some flack for it. But I believe it causes less smearing and a better tasting spirit. If you have the money and time... I would at least keep it two inch from the tee thru to the condenser. That's what I was told when I was doing my build .. good luck

[MooseMan]

Totally agree with Wildcats on keeping it the same up until the PC, just like you've got it showing in your render StillCity.

The reducer Kim has shown is perfect for the job of getting you down to a nice diameter for your PC.

Incidentally, the I.D. of 1" SS fittings will slide over 22mm copper with just the lightest polish, and solder will flow right around that like it was made to be there.

[Salt Must Flow]

There are 3" tees that reduce to a short 2" vapor takeoff like shown on this page. If you shop around you'll likely find a better price. You could use a 3"x3" short tee too. What I like about this type of tee is that smaller concentric reducers and elbows are significantly shorter (3" long) and compact in comparison to fittings of larger sizes. To me the combination of fittings look better, less bulky/awkward, appears to be a better configuration of parts and worth spending a few more bucks. I just don't like having an unnecessarily long combination of parts protruding from the vapor takeoff.

I used a 2" x 1-1/2" concentric reducer for the vapor takeoff and installed a thermowell there (to monitor the vapor takeoff temp.

I then used a 1-1/2" elbow with a 2" end cap with 1-1/2" weld cutout TIG welded to it in order to connect my 2" shotgun condenser directly to it.

Since you don't intend to use a gate valve, your vapor takeoff would be significantly shorter than mine. Technically you could always add a gate valve if you ever want to switch to VM. That's modularity for ya.

[PLAYMP]

There are 3" tees that reduce to a short 2" vapor takeoff like shown on this page. If you shop around you'll likely find a better price.

I will call out this great little “gin basket” fitting that I use for my VM:

https://a.aliexpress.com/_msjm6Ow

It’s an offset cross that has 3” connections vertically and offset 2” connections horizontally. I clamp on a 2” tri clamp Auber probe to measure my takeoff on the lower port and the upper port is my takeoff: 2” gate valve to a 2” elbow to a 2” shotgun condenser.

[MooseMan]

Jeez this is getting complicated, We're gonna fry the mans brain with options! Haha

[Wildcats]

Maintaining a consistent diameter in the vapor path (from boiler through to the condenser) is critical to a smooth, linear takeoff. (Avoid choking down to smaller (1/2") diameter tubing like you see on the commercial stills - these will kill your product quality and create prohibitively long run times). 2" minimum is ideal.

It is vital to remember that a still requires condenser knockdown power equal to the amount of power one is putting into one's boiler. For a keg, this means larger than a (single vapor-tube) liebig. If your condenser is not capable of handling power input you will have to reduce power, extending the run. Even worse, an undersized condenser (and vapor path) can create smearing in the boiler and your product.

This is copy and pasted from the advice I was given when building my still. It is from a long standing member here on HD. (Greatly respected and experienced) This is what I meant when I said that you don't want to restrict the vapor path...

Now as I understand it.... This does not apply to the type of still above... The valved VM. That type of still is reduced down for a smaller valve and I think a set reflux ratio.. I could very well be wrong about the valved VM.. that just the way I understand it.

Having said all that. I am still very new to the craft of home distilling. So needless to say there is a ton of information and practical experience, that I have yet to learn. That's one of the things I love about this hobby. That and the fact that I get to make my own whisky.
I felt I needed to explain my earlier statement. Hope this helps man.

[kimbodious]

This thread is a CCVM build thread. On CCVM’s the valve is before the offtake. VM type solutions involving restricted offtakes and valves after the offtake are distracting.

[Sporacle]

It is vital to remember that a still requires condenser knockdown power equal to the amount of power one is putting into one's boiler. For a keg, this means larger than a (single vapor-tube) liebig. If your condenser is not capable of handling power input you will have to reduce power, extending the run. Even worse, an undersized condenser (and vapor path) can create smearing in the boiler and your product.

A properly built and sized liebig will handle a crazy amount of power and are 100% suitable to a keg.
Mine would happily knock down everything I could throw at it on my 50l keg

It also has the added advantage of moving the output a good distance from the heat source if you are using gas or wood.

Shotguns are nice and flashy but the simple liebig is a great bit of kit