Brass Gate Valves On Vapor Take-off?

[NineInchNails]

I've been searching for a reasonably priced 1" stainless gate valve with PTFE/teflon seat and as I'm sure you all know ... they are damn expensive.

Now I started hunting down brass gate valves. Super cheap! I did a few searches here on AD and cannot find much specific info on using brass valves on a the output of a VM or any reflux still. I’ve read that many ‘delead’ their brass valves using a vinegar/peroxide solution. Many threads speak of using brass valves on other things, but not much specifically for outputs. In your experience, do you think that this is a wise idea or just something that ‘some’ do out of precaution?

If you guys do use brass valves … I assume you are just getting them at the local plumbing/hardware store and making sure that they have a PTFE seat right?

I just found a 1" stainless gate valve on eBay for $35 (with free shipping) and thought what a great deal! Instead of 'buying it now' I chose to send the seller a question. They guy replied by saying that it is NOT a gate valve at all ... it's actually a globe valve. The title for the item AND the description is 100% incorrect. I thought I'd mention that to you guys in case you find it.

Ya think I should just shell out for a 1" stainless gate valve or a stainless ball valve for less? I just assume that a gate valve would be 'ideal' and I may regret not getting one if I just got a ball valve.

Please let me know your experiences because right now I'm just making assumptions

[stillton]

if you can see that the sealing material is white, you can be pretty sure its ptfe. if its black, dont buy it if you dont know the exact spec.

if the valve has a typical globe valve shape, there shouldn't be any problem to confirm that it is a globe valve if you got a picture of it.

how important the deleading is depends on the lead content in the valve. I heard it can vary from 0% to 5%, but i got no source for that at this moment.

[myles]

Gate valves are designed to be used either fully open or shut. They are very non-linear in the partial open mode. OK for coolant lines etc. Globe valves are also "stopcocks" intended to be open or shut. Ball valves are better in the product line. Stainless is what you should aim for.

[stillton]

Gate valves are designed to be used either fully open or shut. They are very non-linear in the partial open mode. OK for coolant lines etc. Globe valves are also "stopcocks" intended to be open or shut. Ball valves are better in the product line. Stainless is what you should aim for.

with a sensitive temperature probe a bit down in the column, a simple on/off type of valve works very well in any VM/LM ARC. much less hassle then a linear valve that needs controlling from more then two sensors and probably some fussy logic to work good. and i very much doubt that would increase the output speed by more then a few % against a well calibrated on/off setup anyway.
snuffy will hopefully prove me wrong some day, but to date, his works stand above any "normal" hobby distiller when it comes to this subject. and i will not revise my stand until we see a working design suitable for the average hobby distiller.

[NineInchNails]

Gate valves are designed to be used either fully open or shut. They are very non-linear in the partial open mode. OK for coolant lines etc. Globe valves are also "stopcocks" intended to be open or shut. Ball valves are better in the product line. Stainless is what you should aim for.

So a ball valve is the way to go then and not a gate valve?

I always thought that gate valves provide more precise control because they can be closed partially in small increments. So that isn’t true in the case with vapor take-offs?

[NineInchNails]

Gate valves are designed to be used either fully open or shut. They are very non-linear in the partial open mode. OK for coolant lines etc. Globe valves are also "stopcocks" intended to be open or shut. Ball valves are better in the product line. Stainless is what you should aim for.

with a sensitive temperature probe a bit down in the column, a simple on/off type of valve works very well in any VM/LM ARC. much less hassle then a linear valve that needs controlling from more then two sensors and probably some fussy logic to work good. and i very much doubt that would increase the output speed by more then a few % against a well calibrated on/off setup anyway.
snuffy will hopefully prove me wrong some day, but to date, his works stand above any "normal" hobby distiller when it comes to this subject. and i will not revise my stand until we see a working design suitable for the average hobby distiller.

Do you mean that the vapor take-off should be sized appropriately in relation to the column diameter to designate a specific reflux ratio therefore only requiring that the take-off valve be either completely open or completely off? If that's the case then the valve should only need to be either completely closed or completely off right? Therefore having valve capable of incremental control is unnecessary.

Maybe I’m WAY off and misinterpreting what you wrote

[stillton]

Gate valves are designed to be used either fully open or shut. They are very non-linear in the partial open mode. OK for coolant lines etc. Globe valves are also "stopcocks" intended to be open or shut. Ball valves are better in the product line. Stainless is what you should aim for.

with a sensitive temperature probe a bit down in the column, a simple on/off type of valve works very well in any VM/LM ARC. much less hassle then a linear valve that needs controlling from more then two sensors and probably some fussy logic to work good. and i very much doubt that would increase the output speed by more then a few % against a well calibrated on/off setup anyway.
snuffy will hopefully prove me wrong some day, but to date, his works stand above any "normal" hobby distiller when it comes to this subject. and i will not revise my stand until we see a working design suitable for the average hobby distiller.

Do you mean that the vapor take-off should be sized appropriately in relation to the column diameter to designate a specific reflux ratio therefore only requiring that the take-off valve be either completely open or completely off? If that's the case then the valve should only need to be either completely closed or completely off right? Therefore having valve capable of incremental control is unnecessary.

Maybe I’m WAY off and misinterpreting what you wrote

im not taking the column diameter in to calculation here. at least not without taking at least 5 more perimeters in to consideration.
lets determine the valve size fit for your column using an exact manual valve, no matter the diameter, type of packing or vapor speed...
first bleed of the heads very slowly. after this is done, write down the exact temperature your thermometer gives you in the column. this is your reference value.
open the valve to what you estimate to be full take off speed without getting any tails in your product. now either increase the output if your temperature is at your reference value or decrees it if it goes 0.1C above it. this way you will find the maximum size of the output valve that your rig will handle at optimum condition.

fit an electrical valve with that diameter, or a bigger one with a narrower fitting according to your spec. this will ensure you that the steam wont shoot out (out of control), disturbing the equilibrium.

when the tails ratio increases in your mash, it will rise in the column. this will be detected by your thermo probe sitting about a feet down your column. so before any tails reach the vm-arm, your valve will shut, and your column will go to 100% reflux until the tails sink down below your thermo probe.
this is way more faster, and more exact then any PM controlled "LM" system, and wont disturb the equilibrium in the column if its calibrated by the method mentioned above.
a linear valve acting on multiple sensors will keep your column at optimum speed, and perfect balance throughout the run, but my personal belief is that it will only give a slight advantage on the end result. if not, its still much easier to add a foot to the column to compensate for this relatively small "instability" then to make a "perfect" ARC. at least for noobs like you and me

[NineInchNails]

Well this was the overall ideal so far. It's all completely stainless 3" pipe with copper mesh packing. The propane burner that is depicted is what I happen to have on hand right now and stands approx 17-1/2" tall. I will be rid of that thing some day and get a lower profile burner so that I can add more height to the column. I can make column extensions pretty easy so that shouldn't be a problem. At the moment the drawing shows the column at approx 4' 6" in height (until I add extensions some day). I have a 9’ 6” ceiling so I do pan on making the most of it. The vapor take-off is 1" leading to a 1" valve. I know I can get rid of one of those elbows just before the Leibig and I likely will.

The condenser is drawn to be approx 9" long and a double wound coil (perhaps 1/4" ID tubing). Beneith the condenser I have drawn a reducer collar (perhaps not needed) which reduces to approx 1-1/5".

The Leibig is 1" over 2/4" and I can make it as long as need be ... I'm thinking of making the water jacket portion approx 4' long? The copper pipe is purchased in 5' lengths so I do not mind making it a bit on the long side. I have not constructed most of this yet so nothing is written in stone. I haven't even made the Leibig, but I've priced out all of the parts. At the moment I'm more in the planning stage.

Here's a direct link because the picture doesn't show up in full size: http://i639.photobucket.com/albums/uu11 ... MSTILL.jpg




Shit ... neither pic shows up full size Hopefully you get the idea. Any advice or heads up would be appreciated.

[stillton]

For some reason i thought you were talking about an electrical valve before.
in a manually controlled rig you definitely need to be able to fine tune the valve precisely.

maybe you should consider putting a piece of pipe before the condenser to use the "chimney effect".
if you put the valve in a horizontal position, maybe you could get rid of that extra bend before the liebig.

[Tracker]

I realise that for most, I am preaching to the converted but here goes anyway.

Gate valves use no seat material, metal to metal wedge seal and the opening gap commences from the bottom as a slight arc shape until it finally gets to a full circle opening. This action requires many turns of a shaft to accomplish.
Ball valves begin by providing a small arc opening on one side of the pipe which is directed through an opening in a ball to the opposite side until the valve is fully open when a full circular vapour path is available.
These valves use a system of "O" rings or a moulded assembly as seals.
A butterfly or plate valve is the same as a carburettor valve which is a simple plate which either seals a pipe or exposes a complete passage of flow by gradually exposing a vapour path on both sides of the opening simultaneously. This type of valve uses seals on the shaft but not in the vapour flow passage.
Both Ball valves and Plate valves only require a 90 degree shaft turn from fully closed to fully open.

As I see it, the type of valve used is determined by the degree of sealing required (both ball and gate valves seal well) as well as the degree of variable exposure required.


Cheers.

[NineInchNails]

Well I'm not 100% sure whether you guys are recommending a gate valve over a ball valve or not, but I am certain that you all are recommending stainless. I've decided to go with a 1" welded stainless gate valve.

I have simplified my drawing a LOT.

[Rebel_Yell]

Nice pics..

You are doing right with the gate valve.

[NineInchNails]

Nice pics..

You are doing right with the gate valve.

Thanks! I am trying to make this thing as interchangeable as I can. That way I only have to swap a long column with a shorter column, slap on a different head, and it's a pot still. I'm even plumbing the reflux condenser through an end cap so that it can be removed and dropped inside of any type of reflux head as long as it's constructed of 3" stainless pipe. I was going to go with a LM for my 1st reflux head, but I figured that I'd cut to the chase and go straight to the VM All that I've read about it leads me to believe that it's easier to operate and hell ... I was planning on using the Leibig for the Pot configuration anyway. Since I'd already have the Leibig ... might as well go VM with the reflux

Just one more parts order and I'll be ready to have all this welded up

[Rebel_Yell]

Git it done!

You are paving the way for folks to follow..

[punkin]

Gate valve has a lot of advantages over a ball valve. Gate valves are indeed designed to be used at incremental openings (unlike ballvalves) but you must remember to set them on the down stroke, otherwise they can creep.

Use a stainless gatevalve, you only have to buy it once.