Homemade arch pan design questions.

[Bmeehan19]

Good morning. Im upgrading my barrel arch this year. It is fire bricked with insulation behind it, it has a ramp to force the fire and heat up to the pans and a blower under the ash grate. The ramp sits about 26” back from the firebox door. Last year I had two hotel pans on it and it ripped really well. It also has a 6” by 18” flat just before the exhaust stack to sit a pan on to preheat sap.

So, this year I want to improve efficiency. I am going to extend the arch another 24” so the pan dimensions will be 18”x48” while maintaining the prewarming shelf. My plan for the flue pan will be either 18x24 or 18x30 with 8 1/2” x 3” deep drop flues. And for my front pan I want a flat cross flow pan with 3 sections, again 18”x24 or 18”x 18” that draws off the rear section. How could I figure out the correct ratio of flue pan to syrup pan? Im using 22ga stainless and doing the fabrication myself. Can any of you help me with the design?

I can only do 3” drops as that is how the firebox wall was designed so I’m limited there. The arch will resemble a classic arch with the thin box under the rear pan to channel the hot gasses.

Sorry forgot to mention that each pan I was thinking would have 3 sections each.

I also have an RO if that makes any difference.

[maple flats]

Older pans were often equal length, such as 2' on each for 4' total, but that was before R.O.'s. My arch is 8' long and it originally had a 3x2 syrup pan and a x6 flue pan. I ordered a new set of pans 3x3 syrup and 3x5 flue. Running concentrate in anywhere from 8% to 13% sugar, that seems to do well, the syrup still has enough time to develop a great taste. On the new super R.O.'s getting high concentrations, like 30%+ they run a short flue pan and a long syrup pan to give the syrup time to develop the taste needed.
For you, if not going above 15-20% concentration, a pan set with 35-40% of the total being syrup pan and the rest being flue pan should be good.

[Bmeehan19]

Awesome! Thank you for the reply. I will probably only have 6-8% concentrate. I will figure out the dimensions.

[maple flats]

6-8% will surely shorten your boil time, but it might tend towards darker syrup, if you go to 12+% it tends to get lighter. It all depends on what you want, my sales are about 3/1, dark vs. Amber & Golden combined.

[Sugarmaker]

To my knowledge there is not a exact ratio of rear to front pan. I have seen it all from a 6 foot rear and 2 foot front to a 6 foot rear and a 20 foot front. Your R.O. is now the work horse in your system. it will do the work for your evaporator, saving you time and fuel.
My pans are 5 x 3 flue and 5 x 3 front (old school). Most of the cross flows only have 2 partitions. Just need to plan where your syrup goes into the front pans and where you want to draw off. I prefer the systems that draw off at the back of the front pans where the fire is the hottest. Also are you going to make it so your can draw from both sides?
Sounds like you have a plan.
Keep Boiling!
Regards,
Chris

[Bmeehan19]

I have a “kinda” plan based on a couple years of reading through this site. I am planning on a 18x30 in drop flue pan. With 2 dividers (3 sections) running front to back. Then taking off the right front corner, through a 1” tube to the front right of the syrup pan. The syrup pan will be 18x18 and will have 3 sections running left to right and drawing off the back left corner. I have to have 3 sections otherwise my transfer tube will interfere with the draw off port. Would 2 sections be better in the syrup pan? I cant really concentrate more than what I have as I’m using a ro based off the RO bucket with 4 400 god filters at 180 psi. Unless I run it twice, I’m unsure what I will get but my plan was to run it into a head tank direct from RO

Also didn’t have plans to draw from each side, is there a great enough benefit that I should consider it?

[Sugarmaker]

Bmeehan,
Drawing off on either side can help clean the front pan of niter. But your plan will work fine. Just keep a eye on niter build up near the draw off area. I like your idea of drawing off at the back of the front pan! Should work well. We need pictures too!
Regards,
Chris

[Bmeehan19]

It will take a bit to bend and weld it all but I promise. I will post pics. Thanks for everyone’s input.