Home made Copper VM Valve

[YHB]

Having decided to add a VM take-off to my Bok, I had a look round for suitable control valves and decided to make one of my own from copper.

[YHB]

Due to other commitments it will be a a few weeks before I can try it out in service, but I am pleased with the seal that it provides.

If any one wants further details please drop me a line.

[FIREotter]

Cool. Like it!

[just-a-sip]

although this is genius and very cool looking i think you missed a piece. with there being no sort of seal, packing,or o-ring to make a seal around rotating ports your going to have nothing better then you would if you used a slip joint without soldering it, it will leak. regardless of how tight the fit, without something actually sealing the ports there is no way to stop the water. or vapor or whatever it is your trying to stop. it may work a little but inevitably it will leak.

[Bushman]

I agree with the missing seal but very nice design concept and tutorial. You are definitely on the right track.

[YHB]

no sort of seal, packing,or o-ring to make a seal around rotating ports - but inevitably it will leak.

Two areas for it to leak

1) Up the valve stem and into the atmosphere - the valve bonnet has a full plate and a cap, both with low clearence holes around the valve stem. I have packed the bonnet with PTFE tape backed up with a silicone diaphragm, bolting down the bonnet compresses the packing and seals the stem, the joint seams to hold very nicely and there are no signs of any leakage.

2) Through the body of the valve and along the pipe. - The purpose of the valve is to control the amount of vapour allowed to pass to the product condenser. In the initial stages of the run while compressing heads, zero vapour is required to pass through the valve, You are correct and my valve is not perfect and the valve does in fact pass some vapour, enough to let the occasional drop of condensate form, with perhaps a drop every few of minutes coming out of the condenser, I do not see this amount as an issue.

The valve served its purpose which was to keep me entertained for a couple of hours while I built it and as a cheap introduction into vapour management stills. I believe it is has proved to be more than fit for purpose. However, the control does not seem to be very precise, I do not know if that is a function of this valve or VM's in general, I am now am in the process of making a proportonal vapor splitting system which I believe will be a great improvement on a valve, more about that later.

[just-a-sip]

no sort of seal, packing,or o-ring to make a seal around rotating ports - but inevitably it will leak.

Two areas for it to leak

1) Up the valve stem and into the atmosphere - the valve bonnet has a full plate and a cap, both with low clearence holes around the valve stem. I have packed the bonnet with PTFE tape backed up with a silicone diaphragm, bolting down the bonnet compresses the packing and seals the stem, the joint seams to hold very nicely and there are no signs of any leakage.

2) Through the body of the valve and along the pipe. - The purpose of the valve is to control the amount of vapour allowed to pass to the product condenser. In the initial stages of the run while compressing heads, zero vapour is required to pass through the valve, You are correct and my valve is not perfect and the valve does in fact pass some vapour, enough to let the occasional drop of condensate form, with perhaps a drop every few of minutes coming out of the condenser, I do not see this amount as an issue.

The valve served its purpose which was to keep me entertained for a couple of hours while I built it and as a cheap introduction into vapour management stills. I believe it is has proved to be more than fit for purpose. However, the control does not seem to be very precise, I do not know if that is a function of this valve or VM's in general, I am now am in the process of making a proportonal vapor splitting system which I believe will be a great improvement on a valve, more about that later.

Well in that case, more power to you. Like i said its a genius build.