Myles your thoughts please..

[Icefever]

I want to ditch my 500 column...I've been reading up on VM columns, this photo..it's small as it's a screen shot from another forum and I can't get it any larger.

I'm very interested in building it as I have odd copper bits hanging about from my beer building days.

As Myles has been popping in of late the question I would like to ask him is..would you change anything about it?? or leave it as it is??

[Anavrin]

Looks good to me, with the offset cooling coil it allows you to take off fores without tainting the product condensor, my retired VM has an inline cooling coil with a side takeoff through a ball valve, it worked really well, probably better for neutral than my currant StillDragon setup, although I haven't used my new SPP packed section yet, depending how that turns out I might go back to VM.

[Icefever]

Looks good to me, with the offset cooling coil it allows you to take off fores without tainting the product condensor, my retired VM has an inline cooling coil with a side takeoff through a ball valve, it worked really well, probably better for neutral than my currant StillDragon setup, although I haven't used my new SPP packed section yet, depending how that turns out I might go back to VM.

The first part of your post is the reason for me wanting to build this.
l was looking at building an hybrid, but I've had an idea of having a tri clamp towards the top of the column, if I wanted I could change the top section and try something else.

[Myles]

This is mine

The only difference now is that I would use a shotgun reflux condenser and not the coil that I still use on my own.

Also on the newer version I have a triclamp connection onto the column. Mine still uses a 54 mm Compression fitting that I just haven't got around to upgrading.

[Myles]

I am sold on the concept of the offset reflux condenser and the external reflux return to the column.

This gives you the option of taking heads off in LM mode via the external reflux return line. You need the reflux condenser just off horizontal so the condensate flows to the drain end. Just a few degrees will do.

If you are working with a 76 mm column I would use a 54 mm reflux condenser, and I use 35 mm for the T and the VM valve.

The last one I built balances nicely on the column because the weight of the valve is set to offset the weight of the condenser. Makes doing up the clamp easy.

I like the brass 54 mm ferrules and polished brass gate valves.

[Icefever]

Myles thanks...in the drawing the gate valve is shown at the top, left of the T section...in the photo's it's way down, would that not create pooling?....or am I missing something??.

[Myles]

In reality what I found is that if you insulate the vapour path in the head and just leave the reflux condenser exposed the entire top section gets pretty hot.

The gate valve itself gets quite hot just by convection along the copper tube.

You might get a little bit of pooling but it is minimal. In the past I have tried to get around it by sloping UP towards the valve. For me I decided it was inconvenient to do so.

The only configuration where I really bothered was when I was using a packed column section above the VM valve as a heads column.

I decided that it wasn't worth the effort.

[Icefever]

Ok ..I've got the picture now....I want to use 3" for the column...2" for the head.
As I'm using 3" on a T500 boiler what height would you suggest?...the section I have is around 5'.

[Myles]

height depends on what product you want.

If this is for neutral you can't go wrong with 100 cm of SPP but it is expensive. Downside is that if you set up a packed column to make neutral, it is difficult to get it to make anything else.

Honestly I recommend a 2 section column. Set up 1 for say white rum with an add on section for neutral.

Scrubbers or pumice both seem to work OK and if you are going to add a section of SPP make it so that you can add it at the bottom.

In the ideal word lets say 300 mm of SPP as a separate section, added to a scrubber/pummice packed column of as much as you can fit in. Modular column so you can increase the height of SPP if you need to.

you can run any column slower if you need a cleaner product with higher reflux ratios.

[Icefever]

My intentions are to make it modular..(as much as one can) one more question in photo 3 with the red handled gate valve, am I correct the column is 3" reduced to 2" then reduced to 1" T??

[Myles]

You can do that.

On mine I use a 76 mm column that reduces to a 54 mm head.

It then reduces to 35 mm into a 35 mm T as the vapour splitter. 35 mm into the reflux condenser and also into the VM valve.

They can be made with 1 inch (or smaller) vapour paths also. So long as you keep the same dimensions to equalise vapour flow both ways it works.

I picked 35 mm originally because it gives higher speed at the end of the run with the valve wide open - IN THEORY.

in reality I leave the tails in the boiler and just build them like that because to me it looks right.

This is one that Minime built a few years back.

[Icefever]

Those dia pipes will do for me...if it works..leave it alone..

Like I said I have the 76mm & 54mm so I only have to buy 35mm & fitting.

I'm thinking about what you said that you would build in a shotgun, how many pipes/size would you put in one? also where would you locate the vent on the head??

[Myles]

Tube and shell reflux condenser. Only built the 1 so far and next time I would put the tubes a bit further appart. This one worked but was possibly a bit tight. Coolant in the tubes and vapour in the shell.

Built this way in 2 parts because each shell end goes into a T.

Mount just off horizontal and the condensate flows to the drain end. Air vent is at the opposite end. Once it is at the correct angle the drain is vertical. It was fitted at that slight angle on purpose. The drain was built with a flared end and fitted into the shell from the inside so it is flush with the inside of the shell.

Tubes soldered in and smoothed off.

The end caps with the coolant conectors prefitted were soldered on last. You could fit the end caps so they are removeable, just in case you ever wanted to clean the tubes. Probably not necessary.

3.7 m of coolant tube should be good for 2.8 kW at full reflex so a bit OTT but this still had 6 kW available. Unlikely you would ever go into full reflux at such a high power level.

Would be real easy to build one with a slightly lower capacity with fewer tubes.

[Myles]

If you ever fancy having a go here are a few tips.Have built a few product condensers like this (except with vapour in the tubes,and coolant in the shell )

1. Cut a 10 mm wide bit of shell tube and take out a thin strip. It goes inside the shell as a depth stop to stop the plates moving during soldering. Otherwise the shell expands and the plate falls down the tube just as you are about to put the solder to it. It gets anoying after a few times!!

2. Flow drill the holes in the end plates. This creates a small socket for the tubes so you can get away with slightly thinner plate.

3. These days i drill holes in the shell and then cut a thread so I can screw in a 10 mm compression fitting. These are then soldered (brazed actually) into the shell before anything else is done. Rock solid coolant hose connection.

You probably don't need the copper washer but it gives a bigger contact area for the solder and looks nice when polished up.

[Icefever]

Thanks for that tip...I'm definitely going for it..the 10mm strip does that stay inside or can you move it to the other end??