Oil Tank Maple Syrup Evaporator

[medic1050]

So to appease my insurance company I had to replace the steel oil tank for my furnace, as it was 15 years old. I replaced it with a fiberglass tank that is rated for 50 years.




So I decided to upgrade my maple syrup evaporator. Last year I boiled in steam tray pans over an open fire between cinder blocks.






I finished building today, as well as tapping the trees. They are calling for temperatures to climb above freezing during the days and dipping below at night all week, so the sap should start running!

I started off by cutting the tank in half and then burning out the remaining oil sludge. This also blistered off a lot of the paint, I will repaint the evaoporator with high temp pain in the summer when it is warm enough for the paint to cure.






I then found an old clapped out woodstove intown for $50. The steel firebox was cracked but really I only wanted it for the door and the flue. I cut them off and attached them to the tank.






Adding a 2"x2" square tube manifols to blow extra air over the fire to improve eficiency a sort of fire supercharger. 1" Ceramic wool insulation behind 2"x$"x9" firebricks should hold in the heat and not over cook the tank.





The final product holds 4 pans one more than last year! Can wait to boil!

 

[davesl708]

good way to put the old tank to good use.:thumbsup:

 

[Wagtail]

Nicely done, Mate. Are you going to transport it to a 'sugar shack' out by the trees or bring the sap back to your place?

 

[motownbrowne]

Looking good. I'm jealous of your freezing temps. There's not one more freezing night in our ten day forecast. We've only had two good sap runs so far. It could be a very short season here.

 

[workinprogress]

Looking Good!

Here is a photo of my oil tank evaporator. I went with the similar design as you. Insulation and then fire brick. Even after hours of running I can still put my hand on the side of the oil tank without burning it. I went with a 6" stack which I think really should be 8". I also put in some metal grates under the fire and ramped the back. Let me know if you are interested I can send a few more photos.

 

[medic1050]

I have tapped 35 trees in my backyard. 25 up the hill from my door on 3/16" tubing running down a 50' drop which should generate a decent natural vacuum. Plus an additional 10 trees right off my back porch in 5/16" tube. Both lines run into barrels. I pick up the barrel with my tractor and drive it to the other side of the house to where I will boil. I don't have a sugar shack, yet. I might build one in the future. I am also contemplating attaching a set of wheels to the evaporator and towing it like a trailer the dozen or so yards to the spot I will boil.

(Use the tractor, see how I brought it back to here?)

I also ramped the back of my evaporator with pieces of steel I cut from the old stove. The flue I attached is a 10" stack so I should have more than enough draft. I was also able to salvage the perforated cast iron plates from the old stove to provide a raised platform to burn on.

If everything works well the only other change I might make is to add air under fire by piping in another manifold under the grate to blow more air up from underneath. From what I have read you barely need to clean out ashes as they are aerosolized and blown out the chimney with an air under fire system. But then I will need a project for next winter... With the additional addition of a proper pan, though that expense will need approval from my wife.

 

[medic1050]

I also decided to weld on an 3/4" axle and some lawn tractor tires. This will allow me to move the evaporator around much easier. It rolled out of the workshop and down the driveway to where I will boil without even shaking a single brick loose. As you can see I collect my sap in the 1000L Tote (250 Gal). I then use a 1 Gal picher to keep the pans full. Next year I will upgrade to a continuous flow raised flue pan, but this year was the arch.


I was a bit over anxious to get boiling. As you can see from the sap line in the pans I didn't even level the boiler before my first test burn. It is now level and boiling great. 2 gal of syrup already sold. If I can make 10 gal of syrup this season on this arch it will have paid for itself.



I have a laser themometer, the outside of the boiler does not get above 70C (158F) the stack temp is 160C (320F) and the temps of the bricks inside is 650C (1202F). This means that most of the heat is going up into the pans instead of out the stack. All 4 pans are roiling boil all the time I feed the fire every 45 min or so. As there is no constant flow, I can't leave it overnight to slow boil, the pans will boil dry. (Learned the hard way. It is a real bear to clean those pans) I have to pull the pans and decant the concentated sap into a trukey fryer pot when I shut down for the night. This dumps a lot of heat every night. With an improved pan next year I should be even more efficient as it can continue to boils more sap as it cools during the night. In the morning there are still some coals in the bottom and the upper bricks are still warm to the touch.