Drop flu Question???

[partsrus1974]

Hello to all!!I have a vermont evaparator 30"x8',I'm trying to make it as effenict as possible.I installed arch board through the whole arch,including the doors and re bricked.My question is,have any of u ever seen any baffles in the arch,on a drop flu??i'm thinking of putting one in to force more heat though the flu's.Does this sound like a good idea?

[maplecrest]

are you burning oil or wood. i have baffles in my oil fired. took the length of the pan divided by three and squeezed the heat in three steps. the final step tight to the bottom of the flues.

[partsrus1974]

I burn wood,Can't afford oil LOL

[maplecrest]

with my wood fired rig i bricked right up to the bottom of the front of the drop flue pan so all the heat went the length of the flues

[Fred Henderson]

My drop flue was new last year and made in Canada. The flue drain is a solid channel near the stack which act also as a baffle. I bricked up to with in 2" of the flues. This thing is a beast for makeing syrup and using very little wood.I build a hood and preheater and although I did not use a water meter I would have to say that I am evaporating about 90 gals an hour.

[Brent]

I've been thinking about this too. Modern wood stoves for use in your living room are trending away from catalytic converters. What they are doing is injecting combustion air from the top near the front glass and setting up a sort of rolling air flow. They have fancy words for this, but it is essentially re-exposing firebox gasses to fresh oxygen. Burns hotter and more complete.

So I've been think of two mods.

Step 1 The simple one would be to stand some firebricks, maybe a whole ones, maybe a split ones, in a few places under the flue pan to generate some turbulence and aid more complete combustion.
Maybe at 90 degrees to the air flow, maybe at an angle like they put on the leading edge of some aircraft wings.

Step 2 is possibly to inject a bit of fresh air at a point maybe 1/3 of the way back from the firebox. Maybe a pipe with a few holes drilled in it. Might not even need a blower if the pipe to the right angle to create some suction.

I guess some smoke stack thermometers would be needed to measure the results.

[partsrus1974]

I do plan on adding a blower to,i was thinking of adding air on top and bottom of the fire with some kinda damper to control witch end gets more air.anyone think thats over kill?I need to get more GPH on this,I was only getting around 40gph last year,but my wood was not the best last season.I have made some changes to my rig like,A hood for my preheater witch is 18x30 copper,Insultated the arch with board,Blanket to fill in the gaps,And nice dry wood for the season!!All ideas are welcome.Thanks for the replies so far

[Brent]

you don't have your equipment listed in your profile. What do you have.

Do you have a preheater on it ?? Hot sap going in is, I think, the single biggest improvement you can do.

[RileySugarbush]

I think about the best improvement you can get with a preheater is 20%, and that is when comparing near boiling sap to near freezing sap going in. Its a good idea and definitely worthwhile, if only for the hot distilled water you get as condensate. A blower and good flow shape that forces the gasses past the most area in the flues is the best first step, IMHO.

[Uncle Tucker]

My arch is new this year so I haven’t made syrup on it yet. I did a test boil and great results. The thing sounds tike a freight train even before I hit the blower. I don’t understand where you would put a baffle on a drop flue. The bricks are no more than a ¼ of an inch to the flues. I think if I added a baffle it would block the flow to the stack. You can see in my pix how close my bricks are to the flues.

[partsrus1974]

I do have a pre heater but last season it had no hood,so it was only getting the sap up to around 80 or so.This year i have a hood so i can't wait to see how hot it comes out now.

[maple flats]

Make sure with your pre heater that you have a condensate tray to channel condensation out and don't let it get into the evap again, other wise you need to evaporate it again.

[partsrus1974]

Yes it has a 1.5" channel all the way around the inside.I have it tappered to one corner,then I soldered in a 3/8" brass fitting to run the condensation into a pail for hot water

[brookledge]

partsrus
You should have virtually no space between your arch and the bottom of the flues. With a drop flue you do not need baffles like raise flues require. Remember that the heat and gasses should be forced through the flues for maximum efficiency. Just put sand or synthetic fabric down until it is about up to the flues.
Keith

[partsrus1974]

I filled the arch with sand and fire brick,its within 2" of the flu's..I also insulated the whole arch.She's ready to BOIL can't wait

[WESTVIRGINIAMAPLER]

Not to tell you what to do, but you really need the stuff within one inch of the flues and 1/2" if possible. Will make a big difference as you will be sucking too much heat under the flues instead of thru them.

[maplwrks]

Like Brandon Said......

[mapleack]

I'd shoot for sand within a half an inch, preferably a quarter of an inch. A slick way to set the sand depth is to measure how far down the flues extend. Next cut a 2x4 about 2ft wider than the arch. Then cut a piece of plywood or sheeting just wide enough to fit down in the arch. Attach it to the 2x4 so it sticks below the 2x4 a quarter to a half farther than the depth of the flues. You can then pull this jig the length of the sanded area in the arch to quickly and accurately set the sand just below where the flues will end up. Hope this helps.
-Andy

[Sugarmaker]

Parts,
You should get about 200 deg F on the sap coming from the preheater. Are you getting near this? Every little bit helps and with 700 taps you want to run as hard as you can or have a lot of time to boil. (I only have 400 taps and that tests me and the old 3 x 10)
Good luck and lets us know hoe the GPH looks after you get it tuned up! Sounds like you have a hood for the preheater that's key. You might need a damper in the stack to control the amount of steam in the hood. But I did not catch where you said you had a drip tray for the preheater? As someone mentioned this keeps the drops of condensate out of the sap. The condensate tray or channels needs to exit out side the pan also. You should get 5-6 gallons of clean condensate water per hour from this rig just dripping off those condensate tubes.

Chris

[partsrus1974]

Thanks guys for all the Info, I will bring it up to 1/2" below the flu's..And Yes sugarmaker I do have the drip tray for my pre heater.700 taps is going to be diffacult with no RO,I had around 400 taps last season and had alot of 12-13 hour nights boiling.Looking foward to all my upgrades this year.This is only my second season on my own I worked for a local Farmer for a few seasons and I was hooked,I had to get into it.I made 85 Gallons last year trying for 150 this year

[WESTVIRGINIAMAPLER]

700 will definitely be easier with the spacing at 1/2" vs 2". Good luck, the tanks will be running over soon!

[partsrus1974]

just imagine last season it was wide open inside,it must have had 14" to the bottom of the flu's..wonder how I boiled as much as I did!!

[WESTVIRGINIAMAPLER]

You will think it is a new evaporator if you push it right up almost against the flues this year.