Air condenser

[Kegg_jam]

I'm guessing that is where the thermo goes.

[googe]

You can see the vent in the top right of the picture, its even written on the pic

[Swag]

Ok, I'm gonna try to help swag out here....at least I hope I'm seeing this right....


Is this your vent swag?

(May not be in the right spot, but at least it's a vent...if I'm seeing it right that is... If it IS A VENT, then it should probably be above the condenser, or Vap is likely to escape....since it is appearing to be in the vapour path....)

I'm guessing that is where the thermo goes.

Yup, that's the thermo port. Steam will vent there if I don't have enough coolant running in the reflux. BTW, my current reflux condenser does not have a vent and works just fine, so that's one of the reasons I question it's necessity. I'm not opposed to putting a vent in if I really need it, but nobody here has presented a compelling enough argument yet. "She's gonna blow up if you don't" isn't quite as convincing as a solid analysis of the physics involved.
I am planning on testing this weekend and will post the results. This is a work in progress and I do appreciate any suggestions you guys may have to improve the design. I also have a family and a full time job so progress may be slow at times, but I'll keep at it.
My gut tells me this will work. It's just a matter of getting the right configuration.

Cheers

[skow69]

Ya know, it wouldn't be hard to replace the cork gun with a curlycue tube and fill it with water, like a manometer.

You could use it to establish whatever maximum pressure you chose, or if it was transparent, to measure the pressure in real time.

Actually, X is the distance the water level rises.

27"w.c. = 1 psi.

[skow69]

And it eliminates the possibility of vacuum on cool down.

[shadylane]

A manometer is a cheap and easy way to accurately measure and limit the pressure or vacuum in a boiler.
If something goes wrong, the water blows out and the manometer becomes a safety vent.
It's also handy for measuring the liquid level in the thumper.
Here's a simple one.

[Swag]

I like the manometer idea, thanks. Simple and accurate. Besides, corks flying around could land in my glass and ruin a perfectly good beer.

[skow69]

In my shed, it would knock a hydrometer off the shelf, guaranteed.

[rad14701]

Let's talk about a vent in the top of the condenser. First off the condenser doesn't need one in order to draw vapor all the way up to the cap. The lower temperature of the condenser automatically creates a low pressure region throughout the interior of the unit. Putting a vent in the top would tend to compromise this vacuum as the incoming cool air would be blowing right into the vent. I can't see anything useful by putting a vent in there.
If there is excess pressure, the output valve can be opened, coolant run through the product condenser and liquid collected accordingly. This way no product is wasted out a vent.
You can turn the reflux condenser completely off and the still will work just fine. You just wont get as much refinement of the alcohol. As long as the output valve is open and the product condenser is running it would merely be a glorified pot still. All the reflux condenser does is provide liquid to drip back down the column.
The only limitation this air cooled condenser might have is not being able to equalize the column at an operating heat level with the output valve closed. I could still run it perfectly safe as long as the output is open and I'm running the product condenser.

Your theory is wrong, and here's why... You DO need a vent on the reflux condenser - period...!!! When vapor collapses it creates a vacuum so you need a vent hole to allow ambient air to be sucked into the reflux chamber... That's just how it works... Your rig will not run efficiently without the vent... You cannot rely on cracking the LM valve to do that job for you effectively, besides being a safety issue... Just put a vent at the top of the reflux condenser already and put this argument to rest... The reasoning you've been repeatedly given is for your own safety and success...

[Hound Dog]

Well Swag, it's Sunday afternoon. Did you get a chance for a trial water run this weekend?

[shadylane]

I hope the OP comes back with info about his experiment.
I'd hate it if the next time I read about this, was on the news......

[Swag]

Your theory is wrong, and here's why... You DO need a vent on the reflux condenser - period...!!! When vapor collapses it creates a vacuum so you need a vent hole to allow ambient air to be sucked into the reflux chamber... That's just how it works... Your rig will not run efficiently without the vent... You cannot rely on cracking the LM valve to do that job for you effectively, besides being a safety issue... Just put a vent at the top of the reflux condenser already and put this argument to rest... The reasoning you've been repeatedly given is for your own safety and success...

I don't know about you, but when the vapor condenses I would much rather have my condenser pulling in more vapor from the boiler than outside air. I don't get much alcohol from the air, but perhaps your atmosphere is different.
Here is the water cooled reflux condenser I've been using:



It has no top vent yet works quite well. It can easily cool all the vapor from my propane boiler without even exploding (or imploding for that matter).
Thanks for the advice, but I'll stick with what's been working for me.

Cheers,

[Swag]

Well Swag, it's Sunday afternoon. Did you get a chance for a trial water run this weekend?

Been a busy weekend! Right now I'm finishing up a stripping run that needed to be done. Had to play golf yesterday, and the honey-do list has been brutal, but I did get the air unit built.



Put a power cord and a switch on the blower, and made an adapter to attach it to from an ABS reducer. The blower is nice and quiet too! The whole still is about 8' tall when mounted on the boiler. I have to step on a chair just to turn the blower on.
Here's it standing up in front of my garage, not mounted yet. (sorry about the bad lighting)



I'll post the results of the test once it's done.

[carbohydratesn]

I don't know about you, but when the vapor condenses I would much rather have my condenser pulling in more vapor from the boiler than outside air.

[Hound Dog]

Well Swag, it's Sunday afternoon. Did you get a chance for a trial water run this weekend?

Been a busy weekend! Right now I'm finishing up a stripping run that needed to be done. Had to play golf yesterday

You had stilling that needed to be done and you were playing golf yesterday? Sounds like you need to get your priorities straight!

Damn man, I have a rebuild I have been itching to get started on but it has been in the teens here. Today was actually nice but I was shoveling out the snow from yesterday. Checked on a wash I have clearing in the garage and it is just slush. First for me. It usually doesn't get this cold around here.

Fire that thing up with water and let us know. Despite the nay-saying and a few reservations of my own I am really interested in your results

[Brutal]

You already know what I think of the no-vent thing, but that air cooled condenser is cool!! I really do hope it works for you.

[Swag]

OK, I ran it for about a half an hour. It did not knock down all the vapor being produced by the boiler, but it did partially work. I could feel a lot of warm air exiting the vents, so it was removing heat.
I think I'm on the right track, but I need a lot more air flow and surface area within the condenser. The blower is capable of putting out a lot more air than was coming out the vents, so they need to be enlarged as well as increased in numbers.
Here's the set up anyway...



Cheers,

[Swag]

An interesting side note... Having individual vents along the length of the condenser, I was able to feel the temperature variation from vent to vent. The bottom one was the warmest and had the most air flow, while the top was the coolest and had the least flow. The variation in flow is no mystery since the highest pressure would be at the bottom due to the the air coming in from the top. The temperature variation is more of a concern. Obviously, hot vapor is not reaching the top of the condenser in any meaningful quantity. Perhaps this is the actual reason for the much debated vent. It would allow more flow into the upper regions of the condenser, making the condenser more effective. I'll give it a try and see what happens.

[carbohydratesn]

Woo! Finally!

Good to hear it's sort of working, I hope you can figure out how to make this work.

[bdizzle6969]

Cool concept for sure it's nice to see some results now, just wondering though how you know it was knocking all the vapours down? Just by temp out cooling air ports? Also you've gotten enough flack about the vent I don't wanna get into that again but I can't see your rubber plug in the picture?

[Swag]

I'm never averse to anything I understand. The vent is not a safety issue for me since I have the column vented elsewhere. It also does not allow external air in to equalize the vacuum as some have claimed, but would rather vent some hot air to allow vapor into the upper area of the condenser. This makes sense to me.
I know I can get this concept to work. It's just a matter of figuring out the proper configuration. I did some calculations on the area of five 1/2" pipes versus one 1.5" pipe and they're not nearly enough. I haven't done the math yet, but I may go to a 2" pipe with 1" vents. That would offer a lot more surface area and additional air flow.

Cheers

[bdizzle6969]

Ok so plug is gone, after skimming through thread I noticed you saying you had planned on changing that setup. I didn't mean to get back to the safety talk at all just wondering if I wasn't seeing something thats all. But I am interested in how you KNOW that it's knocking the vapour completely down, other than the air coming out the top port wasn't hot. Also what we're ambient air temps while you were testing?

[carbohydratesn]

He said it didn't knock all the vapor down.

It did not knock down all the vapor being produced by the boiler, but it did partially work.

[bdizzle6969]

Haha sorry my bad. I'm still kinda fuzzy how you can know that though, with no openings at the condenser and it being a VM leaving product condenser off would tell you nothin as you'll always get vapour no sight glass or anything, just not sure how you can know with any certainty what's going on in there. Sorry if I'm missing something again as I OBVIOUSLY do ,just trying to fully understand

[Hound Dog]

Well if it was not knocking down all the vapor on a water only run, steam would be visible coming out of either the cork vent hole or the VM take off. If it knocked down everything 100%, no steam would be escaping from anywhere.

As a side note Swag, you know it is harder to knock down straight water vapor than ethanol vapors right? I assume you do. If you can take out all the water steam then you will have no problems with alcohol. A good goal to strive for if that's where you are going. Good first shot. Let us know what the next steps are. Keep up the efforts.

[Swag]

Haha sorry my bad. I'm still kinda fuzzy how you can know that though, with no openings at the condenser and it being a VM leaving product condenser off would tell you nothin as you'll always get vapour no sight glass or anything, just not sure how you can know with any certainty what's going on in there. Sorry if I'm missing something again as I OBVIOUSLY do ,just trying to fully understand

It's not real scientific, but I measured it indirectly. I had the output condenser going and the valve partially cracked, and I watched how much liquid was produced with the reflux condenser on, then turned off. The increase when it was turned off was what I assumed that the condenser was knocking down. That and the fact that the air through the condenser was coming out pretty warm meant that heat was being removed from the vapor and condensation was happening to some extent.

Cheers

[bellybuster]

Once again, I am confused (my steady state), I see no valve in your pic. That would change everything.

[Swag]

Once again, I am confused (my steady state), I see no valve in your pic. That would change everything.

You can see it a little better in this pic- right above the product condenser...

[Brutal]

With the valve mounted like that it will pool on top of it when it's closed. I noticed that in your last design too. If you mount it horizontal you can prevent that.

[skow69]

I would NEVER say "I told ya so" UNLESS I needed to bolster my credibility for the next point.

At the start, the column and RC are filled with air (not condensable). Normally, vapor produced in the boiler pushes the air out the vent at the top until vapor fills the column and RC and the reflux cycle begins. Without the vent, vapor production will build pressure and the air will compress a bit, but I don't see any reason to believe the vapor will ever get to the condenser.

Ya, more air flow and vapor contact would help,. but I think you're gonna need a buttload more surface. Stuff as many tubes as you can in there. Maybe stagger them or go side by side. It won't hurt a thing if the CMA of the outlet excedes the input. It's under lower pressure so it needs more room. Check the AC lines and power steering hoses on your car. And think fins. Fins inside the tubes would be cool.