VM / LM Still

[Myles]

Well folks I have been through many reflux still variants but have settled on this one. It suits my purposes, which are mostly for converting the feints from the pot still into a clean neutral that is a base for infused spirits and gin.

I don't drink neutral as such. If I want vodka to drink, I make it on the pot still.

ALL the reflux still variants work, a lot of the decisions made are based on personal choice. This is a compromise. It is good enough but is not what I would build if I wanted an 'ultimate' reflux column.

This is the still head.

I have run this before on a 2" column, but have recently put it on a 3" column. I have not run this yet (and will not for some time) as I am doing a major refit to my still room. All the equipment is getting upgraded.

The condenser is a horizontal double coil. Actually just off horizontal so that all the reflux collects in a reservoir at the end.

The condenser and column stub are in 54mm with the vapour splitting T and branches in 35mm. Reflux return is external to by-pass the vapour splitting T and there is a vapour lock U bend, inside the column.

I generally stabilise for 15 mins and dump the contents of the reflux trap. This I repeat 3 more times. I probably don't concentrate the heads as much as I could by slowly bleeding them off, but it is good enough for me.

I put together this adaptor to bridge the 2" stub into the 3" column.

The 54mm Tank connector only just fitted inside the 76mm end cap. I discarded the synthetic washers, and after tightening the backing ring, soldered the fitting into the end cap. The short stub of 54mm tube was later soldered onto the head above. Once the big compression olive is tightened onto the tube you can undo the fitting and wrap ptfe tape round the olive. The compression nut then only needs to be hand tight to maintain a good seal.

The end cap is soldered onto the column, so I can split the head off the column with the compression fitting.

I went for as much packed length as I could fit into the room (graded pumice gravel) and mounted the column on a small 30 litre keg that I am using as a thumper. The idea is to transfer the entire volatile charge from the primary boiler into the small keg before taking any product at all from the column.

You will note that I included the option for returning the reflux to the base of the column instead of the top. I have NOT tried this yet on any previous columns, but have done it in such a way that that option can be removed later if I wish.

I haven't decided yet which boiler to run this from, but it will probably end up being connected to the glycol double boiler. I am building a new inner pot for that one which will be smaller than my big 100 litre keg.

[YHB]

It looks good but far to many big expensive fitting for me.

I am still trying to figure out how it works. If I am reading it correctly there seems to be a large resovoir behind the LM valve, I thought that was to be avoided?.

Maybe I am looking at the wrong valve.

[Myles]

You are correct, the reflux collects in a reservoir before it returns to the column. On this version the LM side is only used for heads removal - product is taken out the VM side.

You can either slowly bleed off the heads, or cycle the reservoir to dump the heads. Once the heads are removed, that LM valve is shut completely and all the reflux is returned to the column.

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Because you are not taking product through the LM valve, having a pool of liquid behind it is not really a big issue.

It is convenient to be able to split the head away from the column and a compression fitting is comparable to the cost of a triclamp. If you were to purchase sanitary ferrules also, then the compression fitting is probably cheaper.

All the other end feed fittings were used because I am lazy You can build a head like this entirely from tube, it just takes a bit longer. I just wish I had a branch puller - will have to drop hints to SHMBO regarding the next birthday.