Internal Reflux Condenser Jacket

The next step is to build a jacket that fits closely around the core. That will allow a thin, fast moving, layer of water with a lot of surface area to circulate around the core and quickly absorb the heat. In turn, it also allows the condensation rate (both internal and external) to react as quickly as possible to changes in the water flow.

Since the column output is made of 1 ½" piping, we have to reduce this down to 1" piping for the core, and then make the jacket out of 1 ½" pipe. That will leave a ¼" space surrounding the core for the water to circulate.

To do this, we have to do some strange things to the end caps of the jacket so that it will match the underlying core plumbing. Here’s what’s involved:

The hardest part is to cut the right size holes in the caps so they will fit nicely with the core. One cap has a 1 1/8" hole drilled in the end, the other cap, a 5/8" hole.

Cutting such large holes in the caps is difficult if you don't have soft metal hole cutters of the right size. In that case you'll need to use a small drill bit to drill around a circle of the right size. The ragged edges can be smoothed with a rat tail file or a die grinder tool.

When the caps are done, you have to cut two nipples of 1 ½" pipe each 2 ½" long, and a piece 17 ½" long for the main jacket. When you assemble the jacket, the ½" reducing tee outlets should be 18 ½" on center. Later on you will see that it is important to insure that the cooling tube holes in the reflux column match this dimension.

The more important dimension is the overall jacket length. When the core is placed inside the assembly, it should fit snugly at both the top and bottom caps. You can adjust the length of either one of the nipple fittings (before you solder them) to make any fine adjustments.

Now you can complete the assembly by putting the core assembly through the holes in the jacket end caps, making sure the Tee’s are centered along the length. The core and jacket should look like this just before putting them together.

When you're satisfied that they fit snugly, solder the jacket tees and tubing together, again making certain that the tee fittings are lined up in a straight line along the tubing center line.

Then put the end caps on, and install the core. You can adjust the end caps to fit snugly on the core. When everything fits right, solder it together. Then put it aside until we finish the reflux column assembly.