Sand Pot, could it be a salt replacement.

I would suggest a soft fire brick at the bottom for diffusion of the air/gas. I need to upgrade my heat treat too. Hmmmmm
 
I did some more testing and I'm not sure how much defusing is actually needed. It seams like there is a happy medium you can hit with the gas flow where the sand seams to just simmer vs large rolling boil. I did a cold test today and was quite surprised by the results. It seams like the gas is just pressurising the spaces between the sand grains and flowing to the top which causes the sand to separate. Has something to do with the weight and size of the grains and there air resistance. The moving gas causes them to flote. I would bet dollars to donuts that just a simple air supply to the middle of the pot is enoug. You might not get the fluidizing affect at the very bottom but that's would only be a few inches.
I shot a video of the cold test and if you look very closely when I'm able to get the sand in focus you can see it simmering. I'm going to go out now that the sun is down and see if I can video this affect better. Here is the video
http://youtu.be/EdnucicQ-qs
 
JT, the downside to doing with air may be, well, oxygen. O2 plus steel at high temps=not good. More moe thought. Once you get this system perfected, have you thought about selling it? :D
 
I was thinking about the defuser and how it could be easily made. The issue is having a filter thAt has fine enough holes that the sand does not fall through. I relized I had a mild problem today. I was wondering where the sand kept going and come to find out it was leaking out around the air entrance tubing. It's a tight fit but not perfect and when running the air it pushes some sand out of the tiny little gaps. So if we had a diffuser that blocked the sand and still let the air pass then things I think would work better. First though was high temp steel wool and then it hit me why not a layer of inswool. This will take the heat and keep the sand out as well as let the air pass through at low flow volumes. Only problem I could see if lose fibres becoming air born. But the wool could be soaked in a ridigedizer to firm it up.
 
I made a fluidized hopper for a powder coating system once and used copper tubing and ran it down one side from the top then spiraled it in towards the center with a cap on the end and with very very tiny drill holes for the gas to come through. You could do the same thing with a section of stainless steel brake line from the local auto supply store. Then you wouldn't have a hole where the pipe enters at the bottom. If you go up in size this will give you an even diffusion, and cheap to make.

FYI this is not the one I made.

 
Funny you bring that up. I was thinking the exzact same thing. This will make for an easyer build and hole-less pot. Would only work on a proper larger diameter pot. I tried out wool defuser and at least in the small diameter pot I did not notice much if any difference. The only real difference was I was able to insert a steel bar all the way to the bottom and touch the wool where with just the pipe it would stop a few inches from the bottom. But I did video record it and also did a quench test because Salem asked so nicely lol. Once I have wifi I will upload the video.
 
I think the only issue with the coil in the bottom with holes is when you shut off the air the sand will run into the holes and fill the tubing.
 
I guess if you used wire drills, like maybe up to a #70, and had well graded media, the great majority of particles would be too large to fall into the gas diffuser holes?
 
Salem Straub said:
I guess if you used wire drills, like maybe up to a #70, and had well graded media, the great majority of particles would be too large to fall into the gas diffuser holes?
Click to expand...

Why do the holes need to face the top ? Isn't the point to have multiple outlets not necessarily ones that point straight up. And won't the media blow back out if it can settle in? Chris


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I would think that with sand packed in everywhere that it would migrate through the holes regardless of orientation, should they be large enough for the media to pass through... but Chris may have a point, if they can get in they should blow out again. I suppose it's easy anyway to dump the sand out when cold, for maintenance occasionally as needed.
 
I would think putting the holes on bottom would really be the trick way to go. This would cause the air (nitrogen) to disperse even more than with hole on top side, and would help prevent sand from falling into tube.

I think ya'll have a GREAT idea going here. Kudos to you Pleasanthill for starting the discussion.
 
If you cut slits or drilled holes in the top or bottom of the tubing and then did not cap the end of the tube I think it would blow all the fallen sand out the end.

Oh and I fixed the video
 
JTknives said:
I think the only issue with the coil in the bottom with holes is when you shut off the air the sand will run into the holes and fill the tubing.
Click to expand...

put the holes on the bottom of the diffuser tube? Things have a hard time falling up. :D

Edit: apparently I'm not the first to think of the holes on the bottom. Should have read farther down before posting.
 
The issue is even when you shut the air off the sand stays liquid. When you disturbe it then it settles. It's amazing how liquid the sand is when it's fluidised, it would easily run up a hole. In fact when I had the sand pot full and disconnected the air (befor the needle valve) the sand came running out of the air tube like water.
 
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