, "rye_junkie1" <rye_junkie@...> wrote:
> Looking at some of the pics posted in the latest Parrots Beak thread, I was reminded of a question I have been meaning to ask.
> I have seen a few rigs that the connection from the boiler to the column was way smaller than the column. In some cases a lot smaller.
> Ian Smiley does this in his book with the design he lays out. The 1 1/4" column is connected to the boiler(hot water heater)via a 3/4" union.
> I have seen pics of large diameter columns connected to the tri clover fitting on a keg which is in the 2" range.
> How does this affect performance if at all? Does it require you to run at a lower wattage? I am sure that ideally you would want the connection to be the same diameter.
I asked this question to the Amphora folks a couple of weeks ago. The reason I asked them is that I own a PDA-1 which has a 2 inch column but is connected to the boiler with a 3/4 inch fitting. Mike told me that smaller boiler outlet size can become a problem if the back pressure in the boiler becomes too high (apparently there are engineering sites out there where you can figure out the back pressure if you know heat and tube diameter though I did not pursue this) . Back pressure has not been a problem with my PDA-1 because I don't run the gas high enough to overpower the condenser but it could be a problem with my new still. I just completed Harry's crossflow condenser which can handle a lot more heat. I was worried that if I really cranked up the propane, the lid would blow off my boiler with the 3/4 inch connector. Therefore I made a new boiler out of a 20 gallon stockpot. It has a 2 inch copper pipe brazed to a SS ferrule that is TIG welded into the lid. By increasing to 2 inch, I believe I have eliminated the potential back pressure problem unless I switch to a much more powerful propane burner. The crossflow is also stripping faster now with the 2 inch connection but that may be partially due to the fact that I am running the cooling water faster.