Boiling Rate

[jmp]

Ok gentleman, I put together my first 55-gallon drum evaporator and followed advice and posts from others on this great site. I know that many of the answers are in previous posts but seeing that I am pressed for time (self employed) thought it might be easier to get answers again.

The barrel is lined with full firebrick (few unlined areas near stack), airtight Vogelzang door kit, 8' stack. Using very dry firewood, mix of pine and hardwood. 20 gauge SS pan with dividers is 459 square inches. I made the big mistake of not putting the stack on the back of the barrel and making the pan bigger. Anyway, If I did my math correctly I am getting a boiling rate of 3 gallons per hour (no laughing guys) with just water. Ran the rig Sunday to get a feel for it etc. The following are some issues/questions I have. Any and all input would be very much appreciated.

1. Have to keep the door open approximately 1' to get a decent fire going. I was thinking of adding a blower. If I do add a blower, where should it be mounted? Is the stack too tall?
2. Door is not lined. Any suggestions for lining? Is it worth it?
3. Having a hard time getting a good rolling boil closest to draw off. Seems to be a function of not getting the fire going close to the door.
4. Getting flames up into the stack about a foot or so. Too much draft?
5. Feeding the fire about every 5 minutes with two to three 1" diameter pieces. Is this about right for this size/type evaporator?
6. I have heard of others wrapping copper pie around stack as preheater. Any good guidance on how to do this?

Thanks for the input guys I really appreciate it. Already know that I will be building a much bigger rig this summer but want to make the most of what I have this season. :)

John

[SSFLLC]

I believe that i read on here that you need a fire brick wall about 18 inches in and two inches down to get the fire and heat up to the bottom of your pan.

[jmayerl]

did you have to leave the door open in addition to the ash door? I think the grates are the proper distance below the pans but I would stack a wall of fire brick behind the grates too within 2 inchs of the pan, that will force the flame up rather than straight out the stack.

[jmp]

Thanks Keith. I think I have bricked enough. Maybe? Maybe not?

[jmp]

Hi Jmayerl. Yes, I had to leave the door open about an inch. Great suggestion on making a wall of bricks. Will do that later today. Thanks!

[delta757and767pilot]

Are you keeping the wood to the top? almost touching the pan? you should do that.

[Dennis H.]

I found that with that door kit the draft door on the bottom just doesn't give you enough draft to get a good fire going.
I tried to leave the ash door open all the time it just wasn't enough that is when I switched to froced draft. I mounted my blower to come in from the back under the grates. This helped keep the heat to the front of the pan, but it caused me to loose some eye brows and hair!!:D I had to learn to get LOW when feeding the fire. I know it would have been easier on me if I just turned the blower off.

You will want the firebrick to come with in about 1 1/2" under the pan. This will cause the fire and heat up to the pan. You want to make the fire have to go up over the fire brick wall then back to the flue. I never had a problem getting the front of the pan to boil but the back corners because of the flue only being in the center.

A preheater will help but wrapping a piece of pipe around the stack is a touchy thing. 1st it can vapor lock because the sap will boil then turn to steam and not allow sap to flow. 2nd once all the sap is gone the residue sap left in the pipe will scrotch then burn which may give the next batch of syrup a burnt flavor.
I made a preheater for my barrel evap and did not have much luck with it, it raised the temp maybe 15-20 degrees. Now my preheater was just a set of parrallel pipes right in front of the stack that I could swing out of the way once I was done feeding sap.

[jmp]

Thanks for the input delta757and767pilot and Dennis H. I can definitely make sure the fire is larger and I have already added more bricks to force the fire up. Dennis H., do you have any more info on the blower that you are using? I am bald so I stand less to lose in the hair department :)

Preheater on stack issues make perfect sense as well. Sounds like the preheater you came up with was not worth it or is it? The parallel pipes.

I think I have already outgrown the 55 gallon drum but need to make it work until next season.

[jfroe939]

I, too, have a barrel arch that's like yours except it used 2 barrels. I had the same problem with a fire that wouldn't heat well. I didn't have a great draft built into the door to start with so I pretty much 100% of the time have the door cracked. Even that didn't fix the underperforming amount of heat. What DID have some positve effect was I added another 5-foot section of smokestack in addition to the existing 5-footer. That helped it to suck more air. The other big problem that killed the good flame was that after the ashes start to build up under the grate there was essentially no air flow from the bottom-side so all draft was coming over the top of the wood/flame. That makes an excellent grill for bratwurst, but not-so roaring of a flame for this purpose. I have no advice for adding a fan as I don't have any experience with that. If you can find something to stick under your grate and get the grate a little higher up that will help to get the flame closer to the pan and will allow for more air flow under the grate even if ashes accumulate. If you do that, please post your results as I'm looking to make the same fixes as you are. I know more stack helps though.