T size on 2" Boka LM/VM column

[kerberos]

Hi,

Is there any evidence as to which size T is better on a VM take off. I have seen people using 2"x2"x2" or 2"x2"x1" and 1"x1"x1".

I am about to start ordering bits for a Boka LM/VM combo and this is the only part i am confused over.

Any input will be greatly appreciated.

[DAD300]

A 2" x 2" x 2" allows for a minimum reflux ratio of 1:1 (1 part reflux for 1 part takeoff).

While a smaller take off restricts the minimum reflux ratio. i.e. a 2" x 2" x 1" takeoff will only allow a ~4:1 minimum reflux (~4 parts reflux for 1 part takeoff).

Use a "T" the same size as the column and keep the first restriction at least 4" away and below the takeoff. Not parallel to it. Keep the horizontal to a minimum to prevent pooling.

So at the takeoff "T" have a 90 or 45 deg elbow, not a long horizontal run before the elbow.

3" column, 3" "T", 3" 90 deg elbow, then reduction to Product Condenser.

[kerberos]

Thank you for the reply DAD.

I will be using the boka head, plates and needle valve to take off heads and then using a gate valve for the VM. I have just costed a 2" valve and this will be more than the rest of the still! If i go with the 1"valve would a 2"x2"x1" or a 1"x1"x1" T be better?

Kerberos

[Cardinalbags]

First tell us what you plan to make.

For neutrals, you wish to keep a higher reflux ratio and can use a 2x2x1" tee with 1" takeoff and valve then further reduce to liebig. A 1" gate will give you all the control you need for a neutral.

For other products you may wish a lower reflyx ratio and do as DAD300 suggests. You can also consider the reflux condenser controlled VM where the coil acts as the control valve. If you look in DADs pics you will not see a valve.

[Hound Dog]

Look at DAD's design. There is no valve. He just moves the coil up and down. If the coil is condensing below your T nothing will come through. I am not sure how this will work with your boka combo idea though.

Edit: I see this is the same thing Cardinalbags was saying.........

[DAD300]

The Condenser Controlled VM above the LM takeoff would allow both to work.

Removing the valve isn't just about cost, says the Cheap Old Bastad. A valve any where will provide an area for pooling and produce a huge heatsink away from the column.

I posted once before about being able to change a VM to LM with a removable "spoon device."

But make it modular if you can. After using the VM, you'll want to remove the LM portion. A proper VM can collect in drops...even a 3".

[kerberos]

thank you for all the replys.

cardinalbags, i plan on making neutrals and the design of the column i have in mind is similar if not the same as your new still.

DAD300, So a condenser controlled VM above the slant plates? Which will get rid of the valve and the cost, (you don't have exclusivity on the "cheap", "old" or "Bastad" )

We dont seem to have the stainless tube you use over in the UK DAD so will need to look at how i would do this with what i have. I have an idea forming and will post it when i get in.

Thanks to everyone.

Kerberos

[DAD300]

There is a post here of the same design in copper. belongs to jarheadshinner...

http://homedistiller.org/forum/viewtopi ... 17&t=46563

This is one of the few designs that I would build in copper and feel good about soldering it. There are so few joints!

[kerberos]

Just one more question DAD (for now!)
How far past the Vapour take off would my condenser need to go. Assuming normal double coil type in 2" column. I am assuming this is approx 6" depending on water temperature?

[DAD300]

Well at least a couple of coils. My condenser only has five coils and two will stop flow. So say a third of the coil is safe.

If you were to find it didn't stop flow, add a scrubbie lower in the coil.