What is your setup and boil rate?

[maple75]

I was hoping to compile a list of different small scale, homemade evaporator set ups and boil rate, wood usage etc.
I am getting about 5-6 us gallon/hour using four steam pans but using about two face cords of dry spruce/hemlock for a full day boil.
Looking to upgrade again this year and would like to compare some actual numbers to decide what direction I am going.

[Jolly Acres Farm]

I have a W. F. Mason 2x4 XL with blower. I am using about 95% popular and 5% spruce/pine.
Without out the blower I get about 8 GPH. With the blower at 50-60% I get 10-11 GPH. With the blower at 80%+ using wood split no larger then 3x3 and mostly 2x2 size and firing every 8 minutes by timer I got 16.25 GPH, this was not efficient thought and burned at least twice the amount of wood as normal. It is good if you find your drowning in sap and need to process it fast but is no fun and labor intensive. These GPH include start up and shut down. I cut my wood at 14-15 inches long. This setup is fired bricked by the instructions from Bill Mason. I attempted my own fire bricking patterns and got great efficiency but could not get over 8 GPH with the blower running 80%+. The plus size is I ran for 8+ hours on 2 arm loads of wood.
We boiled 839 gallons of sap and made 18 gallons, 12 ounces of syrup with 5 1/2 face cords of firewood.

[Big_Eddy]

For 20+ years, I used a 2x3 flat pan on an outdoor concrete block arch and averaged about 5gph. I tended to run pretty deep (2-3") and would stoke it full so I could do other things while boiling. Firing every 15-20 minutes, I went through CORDS of wood each week boiling sap from 100 trees and had many sleepless nights.

I now run a 20"x 64" home made rig with 40" flue pan (6@5" flues). I regularly hit 20gph early in the season, and slow down to about 16gph by end of season (primarily due to soot between the flues). Firing every 7-8 minutes at 1" dep, I easily keep up with 150+ trees and I burn approximately 1 full cord per 50l syrup.

If speed and efficiency are your goal - flues and and a long narrow arch are the solution - or an RO :)

[ScottyWelden]

I got about 7 gph with 3 pans. My arch is a scrap metal box surrounded by high-temp insulation surrounded by cinder block. I was crazy hot! I used a heavy gauge file cabinet for the box this year, and at the end of the season about 20% of it was gone! I burned dry pine--didn't take a whole lot. Next year I'll upgrade to fire brick for the box--and maybe look into a 2x3 flat pan.

[1220']

barrel stove arch, no fire brick. AUF using 80% hard wood 20% soft wood.
2x2 20 gauge 3 divider pan with a 2x8" pre heater.
3/8" copper tube wrapped around stack before entering pre heater
5-7 GPH

[Tater]

We are using a 2x4 continuous flow flat pan. The first year we hastily propped it up on blocks. This year my cousin made a steel "arch" to put inside the block (his idea - he doesn't spend time on MapleTrader). We put regular Johns Manville R-19 batts of insulation around it and blocked three sides. It warped badly and some of the insulation melted where the steel would glow red, but we made 13 gallons of syrup.

We funneled two high CFM computer fans in under the door for forced draft (not really AUF or AOF), and it helped immensely (esp. since most of our last pickup load of pine slab wood was so green it was wet to the touch and the sap would get all over our hands). Our first boil we got over 12 gph, but we ran the pan so low the bottom would sometimes show in places (our homemade pan isn't perfectly flat), and we had dry wood and little wind. Subsequent boils generally averaged about 10 gph, but we typically ran much deeper so we could be doing other things and not watching so closely.

Our arch was horribly inefficient. We had a half inch gap all the way around the pan that hot air could come out (and scorch the sap splashing up on the sides of the pan). We had no ramp in the rear of the arch, just a 2x4 firebox. The door warped and let hot air out and cold in (with forced draft it could have been sealed). Also, our insulation wasn't the best (blocks were almost too hot to touch after a long boil). We also were limited by the green wood we were burning. We boiled in a lean to that was open on one side and end, and the wind whipped in and stole some of our gph. Our pan was made of scrap stainless, and is probably 12 or 14 ga (poor heat transfer and the pan weighs about 100 lbs).

The forced draft helped to overcome poor arch design, but a "real" arch would have probably further improved boil rates and decreased wood consumption. As it was, we burned two full size pickup loads of wood making 13 gallons of syrup and a lot of memories (like when my other cousin said he would finish the last of the season's sap and left the evaporator for a "bit" and came back to find flames coming out of the pan!)