Propane Evaporator Build

Hi all,thought I would post a bit about my DIY propane evaporator build (be nice now because I am not a fabricator by any means).
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Found this SS cart of sorts at a local auction during the summer and brought it home. I don't have a clue as to what it was used for. It's about 2'6" wide 5'6" long each of the squares you see are 2'x2'.
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I put a couple of wheels on one end and a couple of rubber adjustable feet on the other for levelling the monster. The I cut one end open and stuck 3 propane weed burners in (each burner is advertised as going to 250,000 BTU) that's a total of 0 to 750,000 of adjustable BTU (insert Tim the Tool Man grunt here). Also built a gas manifold assembly everything hooks up to. While doing this work I found a couple of boxes of 24" W x 2" thick Ceramic Fibre insulation so I bought them and installed some into the interior.
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Using a 2'x2' pan and a 1'xx2' pan (also auction finds) I did a proof of concept boil to see if it even would work. Low and behold we boiled water.

More to show but enough typing for the night

Is thw insulation covering the burners? I would think you'd want that open to get the most heat and flame on the pans.

Quote:

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Originally Posted by buckeye gold

Is thw insulation covering the burners? I would think you'd want that open to get the most heat and flame on the pans.

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No, the burners are just above the insulation

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I may however reduce the 2" down to 1" but the ceramic is nasty stuff to work with and not so good for you're health.

Continuing the build,

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In the above picture I've built a bench of sorts to raise the pre-heat pan to be above the boil pan. Didn't take any pictures of the assembly it was an old SS restaurant shelf that I cut up and tack welded together (only have a stick welder and the SS is only 18ga or so so I wasn't able to run a bead).
I insulated the inside again with the 2" ceramic blanket insulation.

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In this picture you see the bench rough set with the exhaust vent (4"x16" w/internal damper) at the back. I don't have any steel left so I'm just going to put a rain cap over it to set my coffee on to keep it hot.

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Above are just a few different views of the unit. Spent a couple of hours yesterday levelling the bench and fitting the cap. Those pic's will follow as well as another timed test boil.

That's it for now.

Looks great! When you test, I'd suggest you see if you can get and maintain a boil in your pre-heat pan if you only add just enough water to cover the outlet. If so, I'd suggest you treat it like a "raised flue pan" (though obviously without the flues). You'll get much more boost in gallons per hour from a second small pan, even if it's only simmering, than you will from a pre-heating pan that's only adding hot sap to the main pan.

You could also add what folks here call "drop tubes" to that back pan, if you want to get even more of a boil. There's a bunch of info here: http://mapletrader.com/community/sho...f-flat-pan-(-)

GO

Great information to know, thanks for sharing.
The thought of "drop tubes" never even crossed my mind. I'll need to keep that in bank for future consideration
Cheers

Well I hauled my evaporator out of the garage this afternoon for a boil out and cleaning.

I filled the 2'x2' pan 2" deep and the 1' x 2' preheat pan with 6 1/4" for a total of of ~12 gal's.
In the timed boil I had the 2x2 pan at a good rolling boil in 26 min.
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It's nice to be able to adjust the burner under each channel of the divided pan.

One design flaw for the preheat pan however, the heat seems to go straight to the vent. I need to put in a diversion plate under the pan (in the bench) Attachment 22872
to force the heat up to the bottom of the preheat pan then out to the vent.I'll do it when I find a piece of steel the proper size.

Some misc pic's

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Shot of the burners

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Rolling boil

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Shot of the stack/vent at over 700deg (only temp gauge I had (off a old BBQ)


All in all I consider the build a success.

Now I just need some Walnut trees to give up their sap.

Cheers

Well after the first test boil I came to the conclusion that I didn't have enough air for the propane to burn properly so I decided to add some air holes

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Put it all back together and heats up much faster now.
I like how this works, now I just need lots of sap.

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Cheers

Nice looking build. Good luck.