salt tube burner...

[hardheart]

So, here's my 24" ss tube for hi temp salts (thanks to Ellis Custom Knifeworks, and I'll be ordering a ceramic platen shortly ) and the fittings I just picked up at Lowes. I'm hoping the two burners will heat more quickly and evenly, and that the top one will help prevent a salt volcano like I've read about (I'll still use a tapered rod in the salt on cooldown) I'm trying to decide where to put the gas inlets. I was thinking of plumbing one line at the 1" tee by the valve for the forced air, or two separate lines at the elbows. Suggestions?

The relative placement is about where they are in the first pic, bottom tip below the base of the tube. I can adjust the lengths easily enough by replacing the 1/2" pipes with different lengths. The other shots are just to show the heliarc welds. Gonna pop some holes in the square piece and run some stainless cable through for moving around.

Those with a good eye will notice the nipples at the tips are two different lengths Either way, I need them at least long enough to reach inside the 2" insulation the body will have, longer if I mix the gas in closer to the flare.

 

[JCaswell]

You don't need the two burners.
One at the bottom is sufficient.

I did the same thing years ago for exactly the same reasons, but discovered that the 'salt volcano' is some sort of myth (unless you've got water trapped down in the tube somehow or something.) I've never had it do more than sputter a bit, and I keep a steel plate set over the top just in case.
I would be dubious about running two burners with a controller anyway. When the thing is up to temp, it'll be cycling on and off pretty regularly, and for short bursts. It's just more complication in your atmosphere that will more than likely result in one or both burners not catching the cycle. If both are out for a few cycles, you're controller won't know it and will keep the gas coming until something happens.
I'd stick with one burner or at least put a valve on each one so you can switch between them as desired.