Oil Tank Evaporator

[HanginAround]

This is the oil tank evap a friend of mine and I made last spring. This was Ver.1.0, and we've changed a few things internally already. Expect to alter it some more before next spring.

http://personal.nbnet.nb.ca/peteb/maple/HPIM0533.JPG

http://personal.nbnet.nb.ca/peteb/maple/HPIM0535.JPG

http://personal.nbnet.nb.ca/peteb/maple/HPIM0545.JPG

[Pete33Vt]

Hangin, Looks great, only question I have is did you change the bricks, or are you going to, seems to me the bricks with holes will let alot of heat through them. The sides of your rig will get pretty hot with those I think.
I would try solid fire bricks. Under them between the bricks and sides I would put in some ceramic blanket. Just a few thoughs hope they help.
Pete

[HanginAround]

Pete, my dad actually sells all that stuff, but the guy that owns the oil tank didn't want to spend any money on firebrick or blanket (he had the red bricks laying around). The red brick worked much better than I thought it would, never broke a single one and the sides stayed cool enough to put your hand on. There was a bare triangle on each side between our gravel and the brick where the paint all peeled off the outside, but we have since changed it around, we put a couple rows across the back of the firebox to lessen the slope on our crushed rock, and extended the brick on the sides back to cover the exposed area. We also made a baffle to go across in front of the stovepipe so we could slope the gravel up straight, close, and even. I think we did pretty well considering we threw it together in a couple days without ever having even seen one made with an oil tank before :D More changes to come.

[HanginAround]

From the Introduce Youself thread:


The fuel tank evap you built is exactly what I had in mind. Have you fired it yet? and guesses on GPH? Is that one continuous pan on top? (no baffles)


Cardigan, we made 6 imp. gallons of syrup, every bit was light, which is rare for a batch pan like this. I think we only got 6 gal/hr, but we have to get some air to the fire or a flue pan to go up from there. We have no grates, so the fire just gets to be a big bank of coals. We are planning maybe a forced air draft or just make some grates and improve the natural draft before next spring. The only draft we have right now if through the door. We also discovered the door should have been a little higher so we can get wood closer to the pan... almost 4 inches now, and hard to get the front 1/4 or 1/3 of the pan to boil at all. Might be much less of an issue though if we improve the air flow. The pan is a single open pan, very light stainless, so I think it would be very difficult to install baffles, although we talked about it lots, not sure if it will happen. I want to change the gravel to ceramic covered steel, since the gravel absorbs so much heat, the darn thing simmers for hours after you let the fire die. The guy that owns it is content with it just the way everything is right now, so an uphill battle to try to get him interested in changing things :? :D Some things we've talked about:

Improve air to fire, either natural or forced.
Baffles in the pan.
A float setup of some sort so we don't have to ladle sap in manually.
Flues in the pan or some other way to improve heat transfer.
Make a steel back ramp out of the top half of the oil tank and cover it with ceramic wool.
Improve the door, maybe insulated with wool or mineral board.
Improve overall insulation with ceramic wool, firebrick, mineral bd.

He's so content now, not sure how many of these things will get done!

[Cardigan99]

Hangin, Wow! looks great. There's my pattern. As far as air flow to the fire goes, it looks like the fire brick is high enough off the bottom of the tank that you could put a draft below the door to vent under the brick. should work with the "pre vented" brick. What's the distance from the brick to the bottom of the pan?

[HanginAround]

Yes, lots of room for a draft, and should help things alot. We were thinking of adding a small squirrel cage fan or something, maybe mount it underneath or behind... if we built a steel back ramp, we could mount it right inside the tank under the ramp, just need some steel cut out for air and access.

I think the door was about 12" on the inside, almost 14" on the outside, so probably about 18" from firebox floor to pan. We could have stood a bit bigger door, but we used one off a woodstove he had. A couple inches higher would be nice.

I think if you are going to have 100 taps, you should seriously consider finding a flue pan... the flat pan is pretty slow. We've tried to think of ways of building a combo flue/syrup pan, or modifying what we have, but working stainless much is kinda out of our league.

[Cardigan99]

yeah, may have to revise downward. Hope to have it built long before the sap flies, so I'll get a sense of it can handle.

[Pete S]

What is the make-up of the arch material that you utilized?

When a large "batch pan" is utilized............and I see that it is firmly secured to the evaporator...........how do you empty it without things gettin' too hot?

I liked looking at your evaporator, as I'd like to build one like it some day....soon, and I like the simple approach of your design.

One of my mental delemas is figgerin' out how to rig a pan that works well to get it empty.

Our current rig takes us about a day for a "chubby" gallon of syrup :oops: .......and things need to change as we've got more trees here to tap! We boil out of a very large aluminum baking pan, about 16x24, on top of an old parts cleaner, it was our first year.

So I'd be happy with 6 gal/day let alone 6 gph!!

It's fun but after about 6 hours or so it's like watching paint dry!

Thanks,
Pete

[HanginAround]

Pete, the arch is just ramped up fine crushed shale from the driveway 8O It isn't ideal, absorbs too much heat, and keeps it evaporating for hours after the fire is out because of the stored heat. However, we have changed a few things since this was thrown together. I've been trying to talk the owner into buying some ceramic wool and making a steel arch out of the top of the tank, but he's happy the way it is, and says we can do anything we want as long as it costs zero, so I guess not much will happen with it. We do have to improve the draft for sure, that's prolly the only major change we'll make in the short term.

The flat pan now has a valve installed in the front corner, but we still have to lift the pan to get it all drained out. Before the valve, we would just boil it as shallow as possible, lift the far end, and scoop some out with a cup, when it was light enough, just pick up the whole pan and dump it in a stainless pail. We never had more than an inch in the pan at a time even when we were boiling. And rate... hmmm, a day for a gallon (finished) sounds about right for us. He only made 7 gals all season.

The reason we had to clamp the pan on is because is very light SS and then they welded a couple patches in it and it all sprung... sit it on a flat surface and one corner is 6 inches higher than the rest LOL.

We were boiling on aluminum roasters on a little wood stove before I talked him into this, so this is a huge improvement. I was a little worried because of all the talk about cooking in Al., especially since it's not like cooking potatoes where they're only in there for 20 minutes, but a slightly acidic product boiling for hours... I figured wasn't a good thing.

[Pete S]

What I dream of someday............I would like to build a 250 gal tank style evaporator, and have enough "technology" and or "tricks" to achieve a rate of aleast 5 gal a day.

That would be a nice way to "grow" our production, as of right now......."Ma" says......."i don't think so!!"

We don't have the time, ambition, or the conditions to boil all night for another GALLON of syrup. We caught two beautiful Saturdays in '06 to boil outside with my folks and friends stopping by.

Thanks,
Pete

[HanginAround]

Decent pans would make a lot of difference, flues increase efficiency substantially, and we've been trying to think of ways to add flues, but neither of us is a welder. Forced air draft would make a huge difference too... and we're thinking of doing that... make some grates and find an old fan somewhere, shouldn't be too big a job. Also, we had no way of preheating, so were continually adding cold sap to our batch pan, which isn't a good thing. Dividers to define the flow would help a lot too, and that might happen maybe not this yr, but sometime. I don't know if you can get to 5 gals of finished product a day, but you could do a lot better than what we are.

[325abn]

Here are a few shots of my oil fired oil tank rig! I bought this off a guy a few weeks ago. He built in while he was in high schhol. The arch looks to be made very well with a lot of steel. It heavy as all hell. The pan is a Small Brothers "lighting". The rig was lined with full fire brick but I am think I will line it 2 layers of ceramic blanket. I was on the verge of buying a weilder to build my own when I found this one. It also has a SS hood for the flue pan.

The guy claimed over 30gal/hr but we will see!

http://i2.photobucket.com/albums/y26/reagantrooper/Evaporator/8-06069.jpg

http://i2.photobucket.com/albums/y26/reagantrooper/Evaporator/8-06070.jpg

http://i2.photobucket.com/albums/y26/reagantrooper/Evaporator/8-06068.jpg

http://i2.photobucket.com/albums/y26/reagantrooper/Evaporator/8-06063.jpg

[325abn]

You could use a electric leaf blower for a blower!

[HanginAround]

He says he should have a fan somewhere, but hasn't dug it up yet. I suggested a powerful hair dryer and we'll disconnect the element, but they and leaf blowers are noisy. But they work! Hope we can find a squirrel cage fan of a good size for a little wind.

Man, I love your combo pan, if you find it missing some night, it wasn't me 8O :D