Will this work for a preheater?

[george sr]

I have been reading this site to learn how to make maple syrup and want to thank all the members who have contributed. After several modifications to my original home made oil barrel arch, I am planning another mod to incorporate a preheater built around the stack. My good neighbor donated a five gallon stainless liquid carrier, which to me looks like an oversized stainless vacuum bottle. The inner container is 9 1/2 inches in diameter about 16 inches deep. The outer shell is 12 inches x 22 inches high. There’s a spout located about six inches from the bottom that goes through the outer shell and connects to the inner container. The neighbor and I brainstormed using this to preheat the sap.
I set up the container on my arch so I could take photos to show what we are planning using some wire to hold things in place. I would have to cut out the bottom to let the exhaust from the arch enter the area between the inner container and the outer shell. I would then cut another hole in the side of the outer shell to let the exhaust exit out and up the stack. Our thoughts are that the hot exhaust would encircle the inner container, which should heat the sap. If you have any comments on this idea, I am open to any ideas or suggestions.

http://home-and-garden.webshots.com/photo/2163168470058241897vxFpKY

http://home-and-garden.webshots.com/photo/2874920750058241897enhzxv

[Fred Henderson]

George, with a design like that you really should be working for NASA. Seriously I have no idea except to tell you to try it with just water.

[george sr]

I think I'll try it with water.

[RileySugarbush]

Very cool! That will do what you think it will, and maybe more. It could easily be more efficient than the rest of your rig and boil sap faster than you can feed the pans. That's OK except you will need to stay on top of it and make sure the level never drops below the top of your internal stack or you will burn sap in there. That means you need to seal weld the stack exit.

Also make sure the top is always open. If it ever got closed/sealed off you have a good chance of making steam faster than your feed spout can relieve it, and we will be reading about you and your neighbor on the Darwin awards.

[Haynes Forest Products]

George Sr; A few observations I like a man thats always trying to keep things level. Those Vacuum jugs aint cheap and I like the way you have it. Are you siponeing it out or do you have a valve out the inner tank thru the flue stack into the first pan? If so thats the area that can burn if the levels get to low and slow. Nice job on the reconfiguring of the barrel I think I hear the sound of a 1000 Sawzals working away as we speak. What did you use for insulation? I see a small blower in your near future.

[Clan Delaney]

That is a beautiful set-up. Very nice work.

[george sr]

Thanks for your replies
Riley
Are you saying it would be better to lower the stack elbow where it mounts to the side of the outer container? I'm planning on using machine screws and nuts to mount the elbow. Do you think it should be welded?
The cap is removable, so thats an easy fix.

Haynes,
Here's a better photo showing the drain valve that does go through the flue into the inner container.
http://home-and-garden.webshots.com/photo/2148413100058241897OQAhEL
I cut a six inch hole in the bottom of the outer shell. Tomorrow I can take a photo to show how the drain enters the inner container. The firebox is mostly bricked, but I need to work on that. I used coarse sand in the bottom of the flue area, but no other insulation.
I do have a small blower going under the tube grates, and am planning to add some air above the fire, but haven't worked that out yet.
I ended up with eight gallons of syrup which was way better then I expected and I did have a lot of fun doing it. I've already cut some iron wood and split it into wrist size pcs for next year.

[Haynes Forest Products]

Now I remember those thing came with bottom drains DAH what you can do is mix up some boiler morter and coat that thru pipe and keep the heat off maybe some fire blanket.
Do I spy a small elec fence transformer on the bench you mite want that on the rig to keep invaders away when your out collecting.:lol:

[RileySugarbush]

George,

All I'm saying is the transition between sap and air on a hot wall like your stack will burn. Just like if your steam table pans were set down into the fire. If the wall isn't constantly wet on the sap side, then it gets very hot and the splashing sap burns a ring on the hot wall. Not that that is a deal killer. Just be aware.

I thought at first that your stack elbow was inside the vacuum bottle and was going to be completely submerged in sap to prevent that problem. But then you would need to seal weld the stack to the inner bottle wall.

Maybe I still don't have a clear idea of what your plan is.

[george sr]

Haynes,
Thanks for the tip on the mortar for the valve tube. Now that I have cut a six inch hole in the bottom of the outer shell, so I can see how things are made in there, I'm thinking that a metal deflector heat shield might work also.
What you see on the bench is a battery charger that I use for my fish locater.
John,
Thanks for your ideas. That's just what I'm looking for. There's a 1 1/2" air space between the inner sap container and the outer skin. My thoughts are to cut a 6" opening in the outer skin and fasten the elbow to just the outer skin. the top of the filler opening will be 6" above the top of the elbow.
I have cut a 6" hole in the bottom of the outer skin so the exhaust can enter the air space and surround the sap container.
George

[RileySugarbush]

Oh, I had it backwards. That makes much more sense.

[jrgagne99]

I see one problem with this setup. What do you do when you run out of sap? You don't want to let the inner preheat reservoir run low, otherwise you'll scorch it. When the fire is going, you always need to have at least 5 gallons of sap in there. Maybe not a show stopper, depending on how many taps you have, 5 gallons might be trivial. For some small hobby guys though, its a significant amount of sap to leave behind.

[KenWP]

He can use water in it to keep it wet. My preheater has to have water going thru it all the time when I run out of sap or it will melt it.

[Haynes Forest Products]

George Im leary of the shields Wrap the tube with a small amount of fire blanket and then put boiler cement around it. I would run the inside vessal full of sap and so scorching wont be the issue. Then when the head tank is getting low of sap shut fill valve to the evap and fill with water/condensate and finish up the sap. Yea you will waste a little sap but so what. Keep up the inventions and carrie on sappy. Put a tee in the fill valve and use the hot water to clean up the sap shack at the end of the day.