Continuous Flow Pan Issue

[jimmyd]

I have a 2' x 6' flat pan that I made a few years back. This year I added some dividers to try and make it a continuous flow pan. My question is, Do the dividers have to be somewhat water tight between them except where it flows from one channel to the other? I'm having a problem getting it to flow properly, seems the temperature is pretty much the same no matter where I check it in the pan.

[johnpma]

Yes the two pans I have had the dividers were welded to the floor of the pan

How are you feeding the sap?

[stoneslabs]

Just a couple of spot welds on the floor of my pan, sugar sand takes care of the rest. Two dividers in a 27 * 30" finishing pan. Works great.

[jimmyd]

I'm drip feeding on one corner and trying to empty on the opposite corner15933

[Bricklayer]

I've got same setup but with a float box. Takes me about 50 gallons of sap before I notice a difference in temp. 100-130 gallons before I'm drawing a little off. Keep laying the sap to it and the gaps will fill with sand and you'll get a gradient.

[jimmyd]

I boiled about 150 gallons last weekend and never saw much of a change in temperature across the pan. Sounds Like I need to close up those gaps a little and try again. I also noticed that my pan doesn't boil at the back under the preheat tank. Could that also be a potential issue?

[Millsy]

How deep are you running the sap? More than likely you just need to keep feeding it more sap.

[jimmyd]

Running about 2 1/2" to 3" deep.

[eustis22]

that seems a little deep to me. I try to max out at 1.5"

[jimmyd]

I'll try lowering the level if I boil this weekend. Supposed to be pretty cold around here.

[SPILEDRIVER]

I run my 2-4 pan at 1 inch its a divided 3 section like yours and feeding the same as you...run it shallower and youll see a huge difference...your evap rate will jump up as well

[jimmyd]

Yea I'm going to try that this weekend.

[wmick]

I'm going to jump in (hijack) for a minute, with my own question about dividers... (as I'm in the middle of a build)

On the professional "store-bought" units, What do the "openings" in the dividers between the sections exactly look like.??
EG. totally open from top to bottom? or a "notch" or "hole" in the bottom corner, etc??? Size of the opening???

I've never laid eyes on one myself, but I'm guessing that it would be an opening at the bottom corner (to promote the denser heavier material to flow through to the next section??)

Thanks

[eustis22]

Mine is a triangular notch on opposite ends.

[wmick]

Mine is a triangular notch on opposite ends.
Thanks - Makes sense... Approximately how big? Width/Height ??

[SPILEDRIVER]

my triangles are 2"..so is the square opening at my draw off box, so I run the sap level half way up the opening

[wmick]

my triangles are 2"..so is the square opening at my draw off box, so I run the sap level half way up the opening

Hmmm - Interesting - I keep trying to overcome my lack of knowledge and experience with some backwoods engineering... I would have thought that keeping the opening very shallow (say - 1/2" - bottom half of the sap) would promote the gradient and denser material to transfer to next section before the thinner stuff on top... But like I said... I'm very green... Learn by doing I guess. :cool:

Thanks for your help...

[stoneslabs]

just my two cents... I run a 27"X7' set up and I have to boil off well over 200 gallons before a gradient is set, 50 or so more before I start my first draw. afterwards, I draw every 45 minutes or so... be patient it will come

[jimmyd]

Yea, patience is not one of my better qualities! I will try and post a drawing of the dividers I made and hopefully I will get some feedback

[eustis22]

sorry for the delay, best guestimate w/o actually measuring is 4" x 4"

[wmick]

Sap Pan divider placement..
Looking for some advice....
Not sure how many dividers to put in my pan...
Had to widen my flues due to some tooling restrictions and it doesn't work out quite right.
See attached... do you think 2 dividers or 4 will work better... Pan is 50" long.

I don't know how it will affect the gradient, etc... but option "A" has about 1740 sq in of surface area on the outside channels and only 975 in the center one...
I'm thinking this might be a concern??

Thanks
16035

[maple flats]

That likely won't hurt it, the movement would simply be a little faster thru the narrower one. On my 3x5 flue pan, there is just one divider and it is open top to bottom at the end about 2" wide. When it gets into my syrup pan, 3x3, I have 4 channels. There are 2 draw offs, one on #1 and one one #4 counting front to back, they flow across the pan. The cut outs at the draw boxes are half circles, 3" wide and 1.5" high. The cut outs at the opposite end of #1 and #4 are 1/4 circles, 2.5" tall and 2.5" wide as is the cut out on the draw off end in the divider between #2 and #3. I reverse flow by closing one 1.5" valve at one end and open a1.5" valve on the other end. Mine has a 1.5" SS tube running from the flue pan, out past the draw boxes, then just out past the draw boxes to the other draw box. Same side draw. I've since seen even better set ups where you can reverse flow but you always draw off from the hottest channel.

[wmick]

Just throwing this back up... Not that I don't trust "maple flats".... but I would, at least, like a second opinion, just to form a consensus, before I weld them in... A or B ?
Thanks



Sap Pan divider placement..
Looking for some advice....
Not sure how many dividers to put in my pan...
Had to widen my flues due to some tooling restrictions and it doesn't work out quite right.
See attached... do you think 2 dividers or 4 will work better... Pan is 50" long.

I don't know how it will affect the gradient, etc... but option "A" has about 1740 sq in of surface area on the outside channels and only 975 in the center one...
I'm thinking this might be a concern??

Thanks
16035

[mellondome]

Is this your only pan or do you have a syrup pan to attach to the flue pan?

[Sugarmaker]

Sap Pan divider placement..
Looking for some advice....
Not sure how many dividers to put in my pan...
Had to widen my flues due to some tooling restrictions and it doesn't work out quite right.
See attached... do you think 2 dividers or 4 will work better... Pan is 50" long.

I don't know how it will affect the gradient, etc... but option "A" has about 1740 sq in of surface area on the outside channels and only 975 in the center one...
I'm thinking this might be a concern??

Thanks
Click image for larger version Name: pan dividers.JPG Views: 31 Size: 40.0 KB ID: 16035

Yes sorry coming in late and not reading the whole post. But you asked. I looked at your A and B proposals. Well this looks a lot like a drop flue pan construction. If this is a flue pan they typically only have a single partition running down the middle. Well thats not going to work well for you (if this is built already?) because you don't have a center top of flue to place a partition. (If not built I would drop one flue center the remaining and add a center partition). The typical partition in a flue pan has a opening only at the rear of the partition. Sap is directed to the front of the rear pan with tubes, one on each side of the central partition. Typically the sap can be turned on or shut off on each tube to allow the sap to flow farther during the boiling process.
So I would not recommend either one. Guess I would need more info as mentioned on your other pan and whether you are switching sides for draw off??
I know this was not the answer you wanted.

BTW it looks like you have the same surface area in both A and B? What am I missing?
Regards,
Chris

[wmick]

Is this your only pan or do you have a syrup pan to attach to the flue pan?


this is a 24" x 50" sap pan, and then there's a 24"x24" syrup pan as well

[Paperman]

Hmmm - Interesting - I keep trying to overcome my lack of knowledge and experience with some backwoods engineering... I would have thought that keeping the opening very shallow (say - 1/2" - bottom half of the sap) would promote the gradient and denser material to transfer to next section before the thinner stuff on top... But like I said... I'm very green... Learn by doing I guess. :cool:

Thanks for your help...

There is so much vertical agitation that there isn't really a vertical gradient. The only reason you get a good gradient in the pan is by the fact you force it to flow by only adding to one end of a long evaporative flow path. Its good to think, just not to deep.

PS I have one divider in my home built flue pan. They answered allot of your questions in the build thread.

http://mapletrader.com/community/showthread.php?10535-Starting-a-flue-pan-build.

[Big_Eddy]

Sap Pan divider placement..
Looking for some advice....
Not sure how many dividers to put in my pan...
Had to widen my flues due to some tooling restrictions and it doesn't work out quite right.
See attached... do you think 2 dividers or 4 will work better... Pan is 50" long.

I don't know how it will affect the gradient, etc... but option "A" has about 1740 sq in of surface area on the outside channels and only 975 in the center one...
I'm thinking this might be a concern??

Thanks
16035


Think of a divided pan as a long straight path, not multiple parallel paths. It doesn't matter at all what the area of each channel is. What matters is the length (gradient) and width (flow rate) of the channel.

On a 24" wide pan, 2 dividers are plenty. With an 8" wide channel, you can get a skimmer down in between as needed to skim scum. Any narrower and you are going to find that once you get it boiling hard, there are issues getting sap to flow fast enough from inlet to outlet. When your syrup pan level starts to drop (from good evaporation or drawing off) the lag for the float pan to catch up and replace that sap will be too long and you will end up with burnt pans. 2 will do.

[Big_Eddy]

There is so much vertical agitation that there isn't really a vertical gradient. The only reason you get a good gradient in the pan is by the fact you force it to flow by only adding to one end of a long evaporative flow path. Its good to think, just not to deep.

PS I have one divider in my home built flue pan. They answered allot of your questions in the build thread.

http://mapletrader.com/community/showthread.php?10535-Starting-a-flue-pan-build.

Man - a blast from the past. I remember your build. Still impresses me. Your float box and mine could be twins!

[Paperman]

Man - a blast from the past. I remember your build. Still impresses me. Your float box and mine could be twins!

Well you were the daddy of the idea. Lets just hope that where the DNA sharing stops!!!! Thanks for the compliments, its all about built not bought here if I can swing it. Too much **** fun making stuff to just whip out my wallet. Been 5-6 years of making liquid gold, CHEERS!!!!