evaporation rate on a flat pan?

[seandicare]

since i've started this crazy hobby a few years ago i've heard all kinds of theories on what evaporation rates should be........i've always been using steam table pans filled deep, and am thinking of investing in a 3x5 flat divided pan for next season. this would be set on my homemade arch (oil tank laid on it's side) over wood fire with AUF possible

i've heard some say a basic rule of thumb was 2gal per hour/sq foot of pan. then i've also heard 1gal would be about right. even heard someone say 3gal/hr (but think they were talking flu pan) is there any kind of rule of thumb for this?

wanting to get an idea if the divided pan would actually up my production enough to warrant the investment....i would probably be using this setup for a couple years until i can afford a real evaporator.

on a side note, does anyone have a general idea what one of these runs commercially? from a metal shop i was looking at i was able to guesstimate around $8-900, but wasn't able to get exact quote yet. not a clue what it would be from a maple supply shop (rather keep the $ local if possible) i am sure it is going to be up a bit more.

thanks for any replies you can give.

[red dorakeen]

I've always read it's 1 GPH per square foot of flat pan.

What sort of rate did you get from the 5 pans.

I got around 5.5 GPH from 3 steam table pans.

If your arch kept all your pans at a good boil I guess you would max out the potential of a 3x5.

I'm new to this so there's probably better info to come from others, though this forum isn't as active as it was during the season.

[MISugarDaddy]

With our prior 2'x4' evaporator we routinely got 15 gallons per hour evaporation rate, using a preheater. We always kept the sap level at 1.5" so we had a good boil. It will depend a lot on how well your arch is insulated and how hot a fire you are able to have in it. The boil rate will drop considerably if you are outside and a cold wind is blowing. You might want to check out Smoky Lake for a pan. He has several listed on eBay for under $600 and you won't find better craftmanship.
Gary

[Big_Eddy]

There are lots of variables that will affect the evaporation rate.
My rules of thumb, assuming a reasonable firing rate with decent wood and under 2" depth and a rectangular pan.

1 GPH flat pan, no blower.
2 GPH flat pan with blower.

Preheaters add 10-25%

Flue pans rates are much more variable, as the number and depth of flues, length to width, and syrup to flue pan ratios make a big difference.