Whats your average evaporation rate?

[Dave Lister]

OK, I am not trying to start a peeing contest or anything like that but I was curious what people get for an evaporation rate?
Basically what do you have for an evaporator, what heats it, do you use a pre-heater and whats the average evaporation rate you get on it? And I guess just for fun, whats the fastest you've ever had it going?

I have a 2x4 wood fired evaporator on a brick arch with a 2x2 raised flu pan in the back and a 2x2 finishing pan in the front. I have a stainless 5 gallon box over the back dripping into the flu pan, but the saps still ice cold.
On average I get about 15-18 gph, but managed to get it up to about 25 gph this last season when I got into some really dry pine.

I guess I just want to know what I can look forward to if I go for a larger evaporator in a few years and realistically how much space will be needed once I get myself into vaccum.

[Dill]

I got my old 2x4 up to 20ish with a blower and good wood.

[mapleack]

3x10 raised flue small brothers with a 7 ft flue pan. When woodfired, under perfect condtions 95 to 100 gph. It's set up for natural gas now, and I guess I'll find out the gph in about a month!

[maple flats]

I have a 3x8 raised flue with a 3x6 flue pan, I like to run at 55-60 gph, can go to about 75 but I need to make a deflector similar to what Leader has on their 2x6WSE to keep the geysers contained in the front of the flue pan. Until then I'll stay at 55-60.

[Grade "A"]

I have a 2x6 Phaneuf raised flue on a home made oil burning arch. I have a home made steam hood and pre-heater. I boil about 45-50gph.

[325abn]

I would say I average low to mid 20s. I have had it really low and really cooking to 28 - 30 but at this level I really gota be on my toes! ):

I am thinking of selling it, anybody interested?

[Fred Henderson]

90 GPH, no blower

[smitty76]

35 an hour forced draft, preheater 2x6 raised flue small bros.

[DrTimPerkins]

OK, I am not trying to start a peeing contest or anything like that but I was curious what people get for an evaporation rate?

First thing ...are you talking evaporation rate INCLUDING or EXCLUDING the syrup production rate? If you're drawing off 2 gal of syrup per hour, you'd need to factor that into your calculations by subtracting it from your total sap processing rate. Evaporation rate typically EXCLUDES syrup production rate. When people mention evaportion rate they usually mean total system processing rate (how much sap you go through per hour). Using evaporation rate also removes the influence of whether you are boiling with sap or concentrate (and the level of concentrate). An evaporator boiling concentrate is going to produce sap at least 4x as fast as the same exact evaporator boiling sap, so the total system processing rate will be somewhat faster, but the evaporation rate is exactly the same.

Given that, the numbers below are from an experiment we did this summer boiling with water...therefore they are evaporation rates EXCLUDING syrup production rates (if you up the number by about 10% you'd be close to total system processing rate). All were done on the same arch, oil-fired. All were a 3' x 10' Leader Revolution evaporator.

Standard Evaporator
Front pan + back pan (no hoods) = 83.3 gal/hr
FP + BP + Steamaway (with hood) = 142.3 gal/hr
FP + BP + SAW + Hood + Plate Heat Exchanger = 152.5 gal/hr

Max Backpan with Enhanced SAW Evaporator+larger oil nozzles
FP + Max Back Pan (no hoods) = 102.2 gal/hr
FP + MBP + Enhanced SAW (with hood) = 175 gal.0/hr
FP + MBP + ESAW + PHE = 189.0 gal/hr

Therefore:

Regular SAW alone increased evaporation rate by 70.8%
Enhanced SAW alone increased evaporation rate by 71.2%
Max BP alone increased evaporation rate by 22.7%
Enhanced SAW alone increased evaporation rate by 23.0%
PHE increased evaporation rate by an avg of 7.5%

Bottom line is that a SAW or or other preheater (steam pan) can greatly increase your evaporation rate and increase your fuel efficiency to a very large degree. A PHE can also help.

The last thing is what we were really focusing on. A PHE uses the condensate from the SAW to preheat the incoming sap. It basically uses what is waste heat to do this. They are fairly efficient, simple and relatively inexpensive. We will be doing considerably more testing of PHEs in maple evaporators this coming season. Will know a lot more in May 2010.

By making all these changes we almost doubled our system evaporation rate, and therefore also greatly increased our total system processing rate (evaporation rate + syrup production rate). The problem....we needed to then get a larger RO in order to keep up with the new evaporator. Adding another 900 taps to our total this year means we really needed it.

[howden86]

515-550 gph

5 x 14 thunderbolt plus piggyback.