Thumper downtube design

[Pesty]

Ok guys.. I've spent the last 2.5 weeks upgrading to my double thumper setup using 2" from the boiler all the way to the shotgun. I've got everything mocked up and will begin brazing and soldering tomorrow. Today is my last fabrication day and I'm stumped on the downtube design.

My question is.. the downtube.

Do I put a bunch of triangle notches, put a cap on the end and make slices along the cap. Drill a bunch of small holes.

I've searched plenty and seen all of the above, just wanted to see what y'all think works the best.

Thanks mucho!

[Kareltje]

Never compared the designs, but I use a showerhead. Bored the holes out a bit to 2 mm diameter, because the original small holes made me afraid they would block.
If you want to know which design is best for you, try them before you solder one in place.

I am very curious about the results!

[LWTCS]

If your running minimal liquid levels in the thumper then you'll want to defuse in order to prevent pressure from potentialy pushing liquid away from your vapor outlet and creating a situation where incoming vapor does not make liquid contact.

If you are running deeper liquid levels it really doesn't matter.
You only need to create phase change.

[RedwoodHillBilly]

I've used small holes just above the end of the thumper downtube, as well as a 90°to a bazooka screen. Both work well. The screen will give better diffusion. This is what I use when doing steam stripping of grain "slop".

[nuntius01]

i've also use small holes along the down tube

[Pesty]

Thanks, good info.
Each one is 3.2 gallons and I plan to start with a gallon in each. I'll have to measure up the pipe how far that goes then notch or drill from there. The notches may be the easiest process but I really like the shower head idea. Gonna take a spin by the home center and see if anything may work.

[RedwoodHillBilly]

For something that small, you don't really need anything more than a simple downtube. If you want you could drill a couple of small holes 10MM up from the bottom, but it isn't necessary for such a small thumper.

[skow69]

I'll have to measure up the pipe how far that goes then notch or drill from there.

All things being equal, you want the vapor to enter the bath as low as possible for longer contact.

[Kareltje]

And in as small bubbles as possible.
But do NOT press the head to the bottom and so block the outlet, like I did a while ago. I had to make an emergency stop and repair it!