Confused about cold finger design

[UKbiker]

From what I can see on how many cold fingers are made, it looks to be simply a water supply or return for the coils. Yet I have found other info stating it is not just a tube but a condenser itself with a cold and hot inlet/outlet.

Could someone explain how a cold finger is made and perhaps how a coil(s) would attach? And a diagram would be great. Maybe I'm complicating things but I also want to make it right the first time.

Thanks!

[rad14701]

There are plenty of examples here in the forums if you take the time to look... Every conceivable type of condenser has been covered... Head over to the New Distiller Reading Lounge and have at it...

[UKbiker]

I have been reading for months. I understand how condensers and heat exchangers work. I know this seems like a very basic question since it is so simple. But I know how to use the search bar and I'm not looking to be spoon fed.

How about I ask a different way. Why does PP say this is not a cold finger? http://homedistiller.org/forum/viewtopi ... 17&t=44788

Or if the search is so easy to use, how about finding a thread that actually discusses the construction of a cold finger.

[rad14701]

I didn't say to search... Forget there is a search feature... That isn't the best way to learn... Just read everything in the New Distiller Reading Lounge, whether you think it pertains to you or not... Sure, I could waste my time finding the proper information for you and post a link but then you'd be deprived of learning everything else you need to know... I can assure you that you'll come away knowing about a simple cold finger and a whole lot more...

[UKbiker]

I have read every word in the new distillers reading lounge, many of it multiple times. Actual details of a cold finger design and construction is not there. Nor is it in this condensers/cooling method forum.

What you say is there, is not. So while you consider it wasting your time, I see it as backing up your claim. It should be easy for you to look at the previously posted thread and explain why PP said it wasn't a cold finger. Especially since that is how most are made from what I can tell.

If you don't know, you don't know. But I have read and read and if a detailed description is on this forum it is buried in a unrelated mega thread. The reason I have not found it is not because of lack of trying. I don't think it is here and I doubt you or anyone else could link to it.

But since you are obviously very well educated on still design and function. Surely it would take a similar amount off time describing it instead of telling me to read. Which I have done a lot of.

[DAD300]

BASIC COLD FINGER...

Cheap easy replacement for reflux coil...

Look at the links in my sig for better and cheaper Corrugated Stainless Steel Coil...

[Prairiepiss]

A coil with a return tube. Is simply a coil with a return tube. Basically you are cutting off a section of the original coil tube. And replacing it with a larger return tube. It is still a coil condenser.

A coldfinger is a type of condenser. That is made of a single outer tube. That has another tube within it. One is feed (outer) and the other the return (inner). Think about it. A finger doesn't have a coil.

A coldfinger and a coil could be combined proper. If a coil was added to a true coldfinger. Then you would want to feed the water into the coil and the outer jacket of the coldfinger. And the return would be up through the inner tube of the coldfinger. This way you would have the counter flow cooling. That you want. Where the cooler area is at the top. And the warmer water at the bottom.

Now we can discuss how efficient a coldfinger actually is?

Lest see you have the cool water feeding in through the outer tube. Being heated. Or should I say removing heat from the rising vapors. So now its hot when it gets to the bottom. Now you feed it back up the inner tube. Where it now induces heat into the actual tube. Transferring to the cooler water in the outer tube. So now the water in the outer tube is not only removing heat from the vapors. But its also removing heat from the hot water returning through the inner tube.

Where a coil condenser. Doesn't transfer nearly as much heat from the return tube to the feed tube. Since there is no physical contact between the two.

[UKbiker]

Thank you!

[lampshade]

Now we can discuss how efficient a coldfinger actually is?

Lest see you have the cool water feeding in through the outer tube. Being heated. Or should I say removing heat from the rising vapors. So now its hot when it gets to the bottom. Now you feed it back up the inner tube. Where it now induces heat into the actual tube. Transferring to the cooler water in the outer tube. So now the water in the outer tube is not only removing heat from the vapors. But its also removing heat from the hot water returning through the inner tube.

Where a coil condenser. Doesn't transfer nearly as much heat from the return tube to the feed tube. Since there is no physical contact between the two.

Mr P,

Let me see if I understand your above statement. (1) The outer coil absorbs heat from the vapor, (2) the return tube emits heat (that was absorbed by the outer coil) into the vapor, (3) the recycled heat is re-absorbed by the outer tube, (4) and so on.

Is this correct? If I stated your theory of operation correctly, I think there is a flaw. In step 2, the return tube cannot emit heat into the vapor because heat transfer is unidirectional: heat moves from hot to cold. And the return tube is alway colder than the vapors.

Maybe, what you said, and I incorrectly did not see it, is that the cooling of the return tube is made less effective by returning the water from the outer tube, because that return water is warmer than it would be if the return tube had its own source of cooling water. But that is also true of double coil condensers.

Sincerely,
Lamp

[Prairiepiss]

It's not transferring heat to the vapors. Unless those vapors are cooler then the water in that tube. However the vapors at the top will be the coolest. So yes the inner return coil could radiate some heat.

I was talking more about the coldfinger. That the inner return tube downstairs make contact with the vapors. But it is making contact with the colder supply water. And will transfer heat to the colder water that was intended to take the heat out of the vapors. Not the returning water.