Will I have a problem with my gate valve?

[Jimithang69]

I may have jumped the gun a little when building my still head but I would appreciate any advice on my design. I haven't had the chance to try it out bc I'm still looking for a suitable boiler. I have a 1.5 x 48 inch column with cooper scourers. And my condenser is a 1/4 inch tube coil on the inside with 3/8 tubing wrapped on the outside for some extra cooling. The weather is finally breaking so I'm looking forward to finishing it up. My only concern is my gate valve. It requires it to be completely closed to back up and drain back into my column. I'll post some picks and I"m sure you'll see what I"m talking about. I'm afraid I won't have as much control of my runs as orginally anticipated. Thanks for the help.

[Ayay]

Nice work!

The coil of plastic pipe will help some - no harm in that.

The reflux return being half way down the column means you will be missing out on a lot of reflux. The higher it is the better; many designs have the condenser on top of the column dumping the reflux into the top of the column. If you mean the condesates have to dam up and flow through the 'T' and elbow into the top of the column then there is a problem - what is the purpose of the lower return pipe?

The gate valve you are concerned about, yes it needs to be closed to get full reflux and 5 or 10ml will have to dam up before it overflows thru the return pipe; but half a litre to overflow at the top will make the cuts quite fuzzy..

The other gate valve is not necessary unless you want the ability to do a reduced reflux half way down the column. The first gate valve will do all that is required because the condensates have to go somewhere - either all back into the column or bleed off what you want while the rest goes into the column.

To sum up I think that lower return pipe should be at the top, without the second gate valve. You can do stripping runs with the only valve wide open, or reflux runs with the valve just cracked open a little.

[1fourme]

Do you have a vent hole drilled into the top cap so it wont build pressure?

[Jimithang69]

I appreciate the help. I put the second valve on the return pipe to stop vapours from entering the the condenser prematurely. And the alcohol will have to dam up and flow back down the return. I could just leave that valve open. Would there be a problem if I ran it at total reflux? And Yes I do have a vent in the top cap. IT is not soldered and I oversized my holes by a 1/16 to give me extra venting along with a 3rd 5/16 vent hole. I didn't want to put too much with the fear of vapour lose. I may try to find a three way valve and put on the bottom of the condenser and then I won't have to dam up the alcohol and will be able to just crack it to take runs with out losing all of my reflux.

[punkin]

They do not appear to be gate valves. They look like ball valves with all the loss of adjustment that that implies. Needle valves are usually used in this application.


You won't have the control you need.

[Jimithang69]

They are ball valves. I was hoping that I could use them as ball valves. Would I be able to regain the control I need if I cut the ball valve off and placed a needle valve at the end of the T coming off my condenser. Will my current set up be better than a regular pot still? Or do you think it would be operational as a reflux still with that modifaction?

[punkin]

They are ball valves. I was hoping that I could use them as ball valves. Would I be able to regain the control I need if I cut the ball valve off and placed a needle valve at the end of the T coming off my condenser. Will my current set up be better than a regular pot still? Or do you think it would be operational as a reflux still with that modifaction?

I am not an expert on anything, and especially not still design. Things i can come up with by learning here though, are;

Does your reflux coil come all the way past the tee to where your pruduct valve is?

If not why have you got the long piece of pipe in there? It would improve your packing height if the reflux portion of your condesate was returned to a higher point in the packing.

Yes, i believe you need a needle valve to get enough adjustment to control the reflux here, and i don't believe you need a valve on the return line.

I don't know what you mean by better than a potstill? It's like saying a car is better than a truck. They are for two different things, although you can carry some goods in a car and some passengers in a truck...