55 gallon evaporator boil rates

[Rozzy]

This is my second year using a 55 gallon drum evaporator and I'm already planning for next year to improve evaporation rates. I'm curious what other folks with 55 gallon evaporators are getting for rates and what have been the best modifications. Basically, I'm not looking to drop the money on a hobby evaporator to make 3 gallons a year, so what can I do to my set up to get the best boil rate? What modifications are the best bang for the buck? I'm currently getting around 3GPH with a 24"x18" pan (flue on top of barrel) and no modifications, I would like to get to 10GPH or better. I was thinking of adding AUF and moving the flue to the rear of the barrel so that I could add a new 2'x3' pan. Also my current pan is 1/16" or 3/32" which seems to take way to long to get boiling so I would like to go with 20 or 22 gauge.

[Daveg]

Your set-up has 3 square feet (24X18) of surface area. Adding a 2X3 pan will probably double/triple your evaporation rate. Sounds like you have good draft with an adequate chimney. You could go with AUF and the additional pan and get close to 10 gph without having to change to 20 gauge.

[ACfarmerNH]

Your set-up has 3 square feet (24X18) of surface area. Adding a 2X3 pan will probably double/triple your evaporation rate. Sounds like you have good draft with an adequate chimney. You could go with AUF and the additional pan and get close to 10 gph without having to change to 20 gauge.

Given the dimensions of a standard 55-gallon drum (22.5 inches by 33.5 inches), I'd assume that not all of the 2x3 pan would be in contact with the flame and you wouldn't see a linear correlation between the old and the new without building the original drum outward.

[CaptT820]

I was getting 2.5gph to 3gph with a similar setup last year. You really cant get too much more out of it than that, just due to surface area and available heat. I built a block arch for relatively cheap money this year and I get right around 8gph when hitting on all cylinders. I figured that this was a good middle step from barrel to hobby evaporator and I could move up if I wanted to spend the money. 8gph with the block arch is good for the amount of sap we get, as we try to boil about 30 gallons per session. If we were trying to boil 50 gallons or more then we'd move up to the hobby evaporator. Its all about the time involved.

[mspina14]

I built and used the barrel stove below for one season:

16181 16182

Had a custom made 24"x32" pan. I added AUF with piping attached to the bung hole and a small blower.

I'd estimate I was getting 3-4 GPH with the blower going. Can't get much more out of a rig this size.

As was said earlier, a rig like this just has a limited amount of surface area.

Mark

[berkshires]

One thing you could do to double the gph is add drop tubes to the pan(s).

Gabe

[DrOriginal]

We just bought a 55 gallon barrel unit this year as well. It kind of just came with the pan. It was such a good deal for the price that we took the unit, it was better then our cinder block setup. Ours has some sides built up on it that allow for a bigger pan:16183
We've had trouble getting good draft this year, might have to fix our chimney or go with a blower next year. But we did find this link from a guy named AndressMetal on pinterest, need to give credit:
https://s-media-cache-ak0.pinimg.com/736x/6e/45/e8/6e45e8dd38fd240b41797ee208dd294f.jpg

We might try to replicate this for our unit, would allow for an even bigger pan, maybe some drops or flues. And would also help with our draft. No idea how cheap it would be, but it's and idea.

[Rozzy]

Thank you all for your responses. I know I am asking a lot for a barrel stove set up, but when I look at a Half Pint or Mason 2x3 I see they throw out numbers between 4-9 gph. The half pint even goes to 10-15gph with the Smokey Lake Full Pint pan. So in my mind, other than the pan, what is $1000-$1200 going to get me with a hobby evaporator that I can't achieve with a barrel stove? My plan was to flair out the edges of the barrel to fit the 2x3 pan, much like DrOriginal's stove. Worst case would be that I don't extend the ends of the barrel and I'm left with a 2'x33" pan much like the half pint. As for drop flues and AUF, I'm curious how much difference they have made for others.

Here is my set up now.
16186

[wobbletop]

AUF is night and day difference. Turn off AUF to feed wood... boil stops. Turn AUF back on... boil starts again.

[CaptT820]

Is the inside of your barrel lined with fire brick? This will determine a great deal of how much you can evaporate.

[Rozzy]

No, currently I have 4" flat cinderblocks in the bottom just to fill the void and get my grates up to just under my door. I also dry stacked a brick wall about 14" in making my firebox 14" deep and 22" wide. The top of the wall is about 3" below my pan. I'm using dry hardwood split no bigger than 2" and a fire every 5-10 minutes depending on how close I can watch the boil. Also I use a hotel pan over the steam to preheat sap for when i need to add a larger quantity but my main feed is a constant drip of cold sap which doesn't seem to affect the boil at that rate.

[berkshires]

What's the inside look like? If it's just one big firebox like Dr Original's you could gain a lot of efficiency (read gph) by creating something to force the heat up under your pan. A lot of people do this with welded plate with bricks/fire-blanket over it. I did it with a cinder-block, firebrick, and fill material (a combination of fire blanket and vermiculite).

Gabe

[DrOriginal]

The fire brick does make a big difference. You can tell when it's cold out and you're boiling you can only stand in the front or back to get warm. But it makes it heavy, make sure you have it where you want it. Used and engine lift to move ours.
And the AUF wouldn't have to be too expensive. Mspina14's looks really nice. But I've seen people use bathroom exhaust fans and small hose to force some air in there. That's probably our 1st upgrade this summer is to get more air in there. I don't think we have a draft issue as much as we have a no air under our fire issue. We've had trouble getting a consistent boil due to our fire. Our barrels fills up with coals to the point it blocks our chimney. Throw some air under it and she should burn everything so hot that the coals are gone.

[wildwood]

I'm running a barrel rig, started with 3x steam pans (flared out barrel and used angle iron to make them sit down inside. Two lengthwise in front, one turned 90* behind them, stack out back of barrel). With firebricks and proper ramp it was no problem to hit 6-7gph once a good boil is going even when the rig was outside. This year I added a foot on the back of the barrel like you'd see on a "real" evaporator and stuck a 2x4 flat pan on it. With that and a real grate it hits 10-11gph easy with no preheater (but inside this year). Since everything is frozen I just added cheapskate AUF and hope to hit at least 12-13gph at full boil. Still haven't figured out what I want to do for a preheater.

How much sap are you running in the pans? The biggest efficiency gain on the 2x4 flat pan for me was getting comfortable running 3/4"-1" (sometimes less if I'm feeling saucy) of sap in it. Scary but man does it boil hard. Never dared run it that low in the steam pans

Good luck!

[DrOriginal]

AUF is night and day difference. Turn off AUF to feed wood... boil stops. Turn AUF back on... boil starts again.

OK, so we didn't wait till next year to add the air.16210
And what a difference. Burns so hot it burns thru all the coals. It's the most consistent boil we've had to date. And only cost us $28. Definitely worth it.

[SyncroScott]

At the end of this (my first) season, I was getting at least 3 gal an hour with my basic barrel arch. It was an improvement over the turkey fryer but not by as much as I had hoped, at least not in gph, but had other benefits though.

Now that I've gotten a solid beginner year under my belt, I've come to the conclusion that many of the cool labor-saving components of commercial operations also make a ton of sense for the hobby folks as well, or more so. Comm ops want the tubing and the ROs and the drop flues to be more efficient since time = money: I want them so I can enjoy boiling with the limited free time I have! I'm hoping I can increase my barrel arch considerably by getting a real 20x30 pan with baffles and then put 33 .75"x6" drop tubes in it, that would nearly double the surface area (4.17sq ft + 3.44sq ft) and get me close to 8 gph without breaking the bank too much. But its all theory at this point... LOL.

[STP92x]

My friend and I built our first barrel evaporator this year and are getting around 3-4gph. We have a fire brick and roxul lined barrel with 2 full size seam pans and run a hair dryer into a pipe under the fire. We think we might be able to get 1-2gph more if it were better insulated and we use some more fire bricks to direct the flames a bit more.