3x6 drop/raised flue questions

[marktripp]

This is my second year with a homemade oil tank arch all insulated and a stainless 2x4 flat bottom chambered pan and a pre heat pan. I'm looking to up my production and cut my time boiling. I'm considering a flue pan and for some reason I liked the idea of 3x6. Not being in the arena very long I thought "hey I'll just buy a 3x6 flue pan, build a new arch out of angle iron and plate steel (because I think I can build it cheaper than buying) and I'll just batch boil like I do now and draw off/add as I go. A good friend of mine advised me that's a pretty dumb idea, he's telling me I should be doing a flue pan with a flat pan in front and finish my syrup on the flat pan rather than handling it again. Makes sense and I know that's how the "real" syrup makers do it. I'm just wondering if anyone can point me in the right direction on learning to use such a set up and give any advise/ideas on raised or drop and if building my own arch is best?

(Sorry for the round about version)

[PerryW]

Yes, you need a flat pan as you can not get close to syrup in a flue pan without burning the syrup. A 3x3 flat pan in front of the 3x6 would work good (my 3x10 has a 3x3 flat pan and a 3x7 flue pan)

I prefer raised flues for the following reasons:

1) there is less change of damaging the flues by throwing wood in too far

2) you can run the flue pan nice and shallow for efficiency and run the syrup pan a little deep to prevent burning.

3) With raisd flues setups, having the evaporator perfectly level is less critical as you have a float fir each pan


The only disadvantage to a raised flue I can see if you have to buy two floats.

Personaly, I would design you setup to reverse the flow so that you can alternate which side of the front pan you draw off from. This prevents nitre buildup near the drawoff area and you can make it though the whole season without having to clean the front pan.

[jrmaple]

It also depends on the evaporation rate you are looking to get and how many taps you are doing; for example, I have a 2x8 evaporator and can achieve 45 gph constantly, sometimes more, sometimes less, depending on draft, wood, depth of the pans etc. If you let us know how many taps you are doing and what evaporation rate you are looking to achieve we might be able to save you some time and money. And yes you always need a flat pan connected with a flue pan or you are running a much higher risk of scorching the flues and burning the setup, and you can get much closer to the finished product on a flat pan. And with any flue pan, you will want a float, it will make life a lot easier and stress free once you get a good boil going and need to walk away for a minute it will always maintain a constant level in the pan. Best of luck.

[marktripp]

I would like to achieve 80+ gph evaporation rate. Currently we have 125 taps and possibility to grow to up around 300+. I'm just looking to get more efficient.

[warners point]

You might think of finding a used 2x6, that would handle 300 plus taps pretty easily. I have a home made 2x6 with a drop tube flue pan and with this last run of 850 gallons on 340 taps in 2 days I'm pretty much maxed out. I was going to expand the arch to 2.5x8, but with the cost of new pans and streching the arch thats a lot of money. That being said we are already planning for a 100 gph ro for next year plus were considering 50 taps on 3/16 tubing. It's a never ending "hobby".

[PerryW]

I would like to achieve 80+ gph evaporation rate. Currently we have 125 taps and possibility to grow to up around 300+. I'm just looking to get more efficient.

A 3x6 flue pan and a 3x3 flat pan should be about 80 GPH. My 3x7 flue pan and 3x3 flat pan does 90-100 gph.

[jrmaple]

Plan ahead, what is your max taps for the next three years? with 300 taps, and say a 3x10 which would boil around 90 gph, you would boil probably every three days or so and a 3x10 would give you a lot of room to grow to around 700 taps comfortably.

[marktripp]

If a 3x6 flue pan will handle 700 taps I think it would be fine. I really can't see exceeding that with the exception of buying some sap besides what I collect. I just need to get away from 8-10 hrs to boil off 100gallons.

[jrmaple]

Then I would recommend a 3x10 unit, 3x6 or 3x7 flue pan and a 3x3 or 3x4 flue pan; then in the future you can add forced air or a preheater and other accessories to improve the efficiency and boil speed. But still, always need the front, flat pan, syrup pan; best of luck.

[lpakiz]

I have a 2 X 10 that has 8 feet of drop flue pan, and 2 feet of flat syrup pan. That combination works very well. Remember, most of the evaporation takes place in the flue pan.

[marktripp]

Do these combination of pans have to be anything special or can it simply be any flue pan connected to a flat pan?

[wiam]

Many different reasons for the combinations. I do not think the 8' flue pan with a 2' front pan would work well with concentrate, but would be fine with raw sap. A lot is personal preference. My "flue" pan is 4' and front pan is 2'. Front pan is not reversable. I should empty and clean about every 20 gallons of syrup. With concentrate I do not think there is any need to reverse a 2x2 pan. Niter covers most of it any way. Probably getting kinda off topic as I'm guessing you're boiling raw sap.

[PerryW]

Do these combination of pans have to be anything special or can it simply be any flue pan connected to a flat pan?

If it's a raised flue, I believe you can just connect the flue pan to the flat pan, though a float box and float in each of the pans makes things much easier (and foolproof). FOr the reasons discussed already, if you are trying build a reverse flow evaporator, you will need float boxes on both sides of the flat pan and and a means to direct your raw sap in opposite sides of the flue pan.

[marktripp]

Many different reasons for the combinations. I do not think the 8' flue pan with a 2' front pan would work well with concentrate, but would be fine with raw sap. A lot is personal preference. My "flue" pan is 4' and front pan is 2'. Front pan is not reversable. I should empty and clean about every 20 gallons of syrup. With concentrate I do not think there is any need to reverse a 2x2 pan. Niter covers most of it any way. Probably getting kinda off topic as I'm guessing you're boiling raw sap.

Yes it's all raw sap I'm boiling.

[jrmaple]

Depending on if you go with a raised flue or drop flue pan, you will need a float box for the front pan as well, and if you have reverse flow then most likely you'll need to connectors from the flue pan to the front pan, and with an evaporator of that size, you would like to have at least three separate compartments in the front pan to prevent the whole pan turning to syrup instead of at one draw off point (if the pan doesn't have dividers then your pan will fill with syrup and most likely burn and it is harder to reliably draw off). Best of luck.