Got Her Running better, but...

[treehugger]

So I got the rig running better. I went from max 25 gal/hr to now 32-33 gal/hr. Syrup pan is boiling better and the flue pan too, but the back of the flue pan is not boiling hard like the front half of it. I have the space between floor of arch and base collar reduced to about 3" If I close this space more will it help the back of the flue pan boil harder? Any suggestions?

[nymapleguy607]

When last did you clean the flues? If you haven't done them in a while that can rob performance. Also what was your stack temp? Mine runs around 1200-1400 to get 40+ gph

[treehugger]

I have been cleaning the flues with every boil. I had her cranking today, and the max stack temp was 950to (probe). I made 1 gal light 1 gal med and 2 1/2 gal dark today. Not bad, i guess i keep getting caught up in the numbers. I just imagined less work with a bigger evaporator. I guess i sabotaged that plan when I had quadrupled my number of taps. I have to figure out how to make my syrup pan boil harder.

[nymapleguy607]

Did you say that you had the Grimm wood saver grates? If so you might want to try and swap them out with drilled firebrick. I tried that this year and got my syrup pan boiling better. To me the woodsavers push just as much heat past as they help to generate.

[GratiotCoMiMaple]

I have a 2x6 Grimm with Grimm 4' raised flue sap pan and am getting a stack temp in the 1000-1100 degree mark with the condar stem stack thermometer. I am running the Grimm forced air unit that may have an undersize blower. It seems to run the best with the draft door open on the first notch. I started with a hump in the arch starting 18" behind the front of the flue pan and extending 12" back and have it up to the rails. I was getting from 25 to 30 g/h. I moved the hump back (kep the front wall the same) to within about 10" of the stack collar and it seemed to push the rate up to an average 30-33 g/h and the stack temp stayed the same. I am getting a great eruption boil on the front half of the flue pan but the back half is not performing like the front half (Is that normal). Not having any issues with the boil at the syrup pan. Sometimes I am thinking it is too hot and wants to foam too much and will not go down the defoamer. I did find that the syrup pan boil can be controlled to a degree by running the wood against the door for most heat and back a bit for less heat.

I would like to be able to run a consistent 40 g/h next season if possible. What are you doing to tweak your 2x6 to run at 40 g/h ? When you mention cleaning the flues would that mean inside the pan our outside the pan? Does a pre-heater help all that much? What do you mean by firebrick with holes in it insead of grates? Do you put the bricks on top of the grates? BTW I am running a hanging hood over the unit. If I built an inline pre-heater in the hanging hood would I run the risk of getting the sap hot enough to create steam and vapor lock the sap flow? Is it always better to use a parallel flow unit?

Thanks,
Kurt

[PerryW]

30-33 gph seems pretty good for a 2x6 with only 4" flues. I think most of them are 7" aren't they?

EDIT: I read it wrong. 4 FOOT flue pan...

[mapleack]

I would say that 950 stack temp is too low for max efficiency. How big of wood, how full is the firebox, how often are you firing?

[500592]

I think he means 4 foot flu pan

[PerryW]

I think he means 4 foot flu pan

thanks. must be double vision.

[treehugger]

Wood is about 3-4". Not all the way dry (oak). And some pry pine. I keep it full,right up to the pan. I fire every 7 minutes. Just cant seem to get syrup from the syrup pan.

[mapleack]

Try reducing your wood depth down to half the height of the fire box to allow more combustion space, shortening up the firing interval if necessary. When I was running wood I got the best fire with the box 1/3 to 1/2 full, adding a couple pieces every 5 min or so. That was with AUF.

[treehugger]

Just out of curiosity, if you fill your firebox full will your front pan
slow down?

[Dill]

Yes the hottest point of the fire, is above the flame. If the wood is right up close to the pan, the hottest part of the fire is hitting the flues. I've been fooling with this, during this season and it makes a difference on mine. I also have AUF.

[treehugger]

The same with me, the front half of my flue pan boils real hard but the back half less. If you run your blower with the draft door open dont you get ashes blowing all over. As far as the 40pan gallons evap rate, i have only been able to get that for one hour. Im mostly 30-32. A friend who has a raised flue set up 2x6the oil burner said his flue pan does that same. So having a volcanoe boil throughout the entire pan is probably a pipe dream. I wonder about the brick idea though. I just think that they maynya maple guy warp the grates if they are put on top. Has that happened to you

[nymapleguy607]

This year I changed out the grates to half bricks with 3 - 3/4" holes drilled through them. My old wood saver grates were starting to sag and what I noticed was I seemed to be blowing to much heat out of the arch. I could get the center of the flue pan to boil but not the outer sections. after changing them to the firebrick I get a lot more even boil through the pans. I must say I do have air under and over the fire in my arch. I think you might want to try spliting your wood in half once. They generally recommend wood be split to about 2-3" for a 2x6. That will give you alot more flame then coals. which will help your flue pan boil harder. What temp does your preheater run at? Mine will generally run around 180-200 degrees that will help keep a good boil around the sap inlet

[treehugger]

My pre-heated sap is usually 180. How do you keep the bricks suspended over the ash pan? And did you drill the holes yourself?

[nymapleguy607]

Yeah I drilled the bricks myself I just got 2 masonary bits, I think 1/4' for a pilot hole and then 3/4". My bricks span the gap over my ash pan, but if they didn't you would make a brick rest out of a piece of angle iron. Do a search on here for Drilling Fire Brick and it will tell you about how to do it. It seemed to help there is definitly a lot less air coming through than with my old grates.

[RollinsOrchards]

If you split your wood into smaller pieces it will burn faster. While that isn't desirable for your house wood stove, the goal of an evaporator is to turn a pile of wood into a jug of syrup in the least amount of time possible. Smaller pieces of wood fed in more often will make a hotter fire.

I find with any fire that criss-crossing the sticks will result in more of an "inferno" type flame, as it lets the air and fire through all the cracks and gaps. This also allows the fire to continue up through the newest layer. Trying to pack them in like your wood pile without any room between can "smother" the fire until the new sticks catch on. Ideally you should be continuing the maximum boil as soon as you close the door after adding wood.

[GratiotCoMiMaple]

The same with me, the front half of my flue pan boils real hard but the back half less. If you run your blower with the draft door open dont you get ashes blowing all over. As far as the 40pan gallons evap rate, i have only been able to get that for one hour. Im mostly 30-32. A friend who has a raised flue set up 2x6the oil burner said his flue pan does that same. So having a volcanoe boil throughout the entire pan is probably a pipe dream. I wonder about the brick idea though. I just think that they maynya maple guy warp the grates if they are put on top. Has that happened to you

I don't have ashes fly out when I have the draft door open at the first setting and when I fire. There are some ashes that fall out but not much. That is why I am thinking that the squirrel cage fan is undersize. If I pick up a larger one I will probably need to put a rheostat on it. I am also not using wood that has been split and dried for 2 years. Using mostly standing dead Ash and Oak with a little Maple mixed in. Sure seems like the hood and pre-heater would help you out more. I was thinking about building a hood and pre-heater or just adding a pre-heater under the hanging hood but if it isn't going to make any difference in boil rate then I will be wasting my time and money.

I would like to see a picture of how NYMaple is using the fire bricks for the bottom of his firebox. Is this just an attempt to reduce the amount of air coming up into the fire. Wouldn't it be the same as slowing down the blower fan?

BTW..........that copper unit is really nice. Would you post up some pictures of it or e-mail me some at shootnfowl@yahoo.com. Are those pans factory Grimm pans? They sure look just like my pans, from what I can see in your avatar.

Thanks and I hope you aren't peeved about me hi-jacking your thread.

Kurt

[nymapleguy607]

I would like to see a picture of how NYMaple is using the fire bricks for the bottom of his firebox. Is this just an attempt to reduce the amount of air coming up into the fire. Wouldn't it be the same as slowing down the blower fan?

I don't have any pictures right now, in a nut shell the fire brick grates reduce the amount of air that comes through the bottom of the fire, but what I like is they don't become plugged with ash like the woodsaver grates. If you slow down the blower I think you would see a drop in your evaporation and alot more smoke out the stack.

[nymapleguy607]

Kurt

A tight fitting steam hood and preheater will generally improve effciency about 10-15%. The best part is hot distilled water for cleaning filters and what not. You can build a copper preheater fairly cheap.

[RUSTYBUCKET]

Kurt -

In this thread, you'll find some pictures of Treehugger's rig.

http://mapletrader.com/community/showthread.php?15198-Copper-evaporator-set-up-almost-done!

[treehugger]

So on the last run i was getting a solid 32-33 gal per hour. Over the past weekend i spoke with a few very knowledgeable old timers about wood fired rigs. They had recommended using ash or maple. I was using oak still had a sizzle. Also they said only load front half of firebox and only half way. I was loading right to the pan. Hopefully with dry /better wood and better technique i should be able to hit 35+ consistently. I am also thinking of putting a damper in as well. I wish i was able to test with sap this year. Guess i'll have to make a "dry" run with water some point.

[treehugger]

Those pans are indeed GH Grimm made. You can see more pics in the gallery on the main page. Thanks for the compliment.

[GratiotCoMiMaple]

Oh Boy. They are beautiful and exactly like my stainless soldered pans that were made in the 1980's .......one my pans is stamped 85 on the brass plate. Not sure if that was the year of mfg, model # or serial number. Very nice. Glad to hear that you got the boil rate up over 30g/h. I have been running dead standing Ash and maple and got a boil rate avg in the high 20's. Tried several years dried blue spruce and could only pull 20 g/h. With dead standing oak I was able to do the best with a little over 30 g/h. All is split into about 4-5" or less. Didn't ever get the stack temp above 1200 degrees and stayed between 900-1000 most of the time.


Those pans are indeed GH Grimm made. You can see more pics in the gallery on the main page. Thanks for the compliment.

[treehugger]

A big producer in my area had two large evaporators. Each the same except one was stainless and one tin. He told me that the tin rig always had a lower stack temp. More heat transfer i guess. The highest stack temp i ever got was 1000. But usually 800-900. Again, that is with semi-seasoned oak and wet pine.

[treehugger]

Do you have pics of your rig? The tin smith that made my steamhood said that my pans were probably from the 1980's, but i could never find any info on them and grimm is no longer in business.