PDA

View Full Version : Finally some Sap



Errin OH
02-22-2014, 11:33 PM
We fired up the new evaporator today. We had test boiled and figure around 12gal hour once up to speed. Numbers pretty much matched. We ran 85+ gallons in 8 hours from match light to fire out. Had 30-40 minutes of getting it up to speed and 45 minutes to shut down. Pulled off a gallon of syrup and left the rest in the pan. I am pretty happy with the results. When I built it I was hoping for 10+ on natural draft. Think I might tinker with the arch and see it I can get an extra gallon or two out of it. Right now it is a flat angel from the fire box to the back of the pan, I am considering a hump to push the fire up a tad higher / tighter to the pan. Front of the pan comes to a boil quicker than the back, and it seems a lot of heat is heading up the stack.

I had the pan custom made. It is a 24x42 with 6 dividers running side to side forming 7 - 6” channels. We do not have a pre heater at this time. Something I need to look into. We started with 2” in the pan and adjusted the flow to match the evaporation rate. Any less and it will not draw off. . About two thirds of the way through I switched to flooding (add 6-7 gallons at a time). Boil down to an under an inch and open the valve to add little more than an inch. This of course stopped the boiling at the back of the pan but within 7-8 minutes it was back.

This brings up a question. The reason to switch to flooding - We use a 15 gallon nurse tank. We pump up to it from the bulk tank. With gravity down to the evaporator the flow changes as the level drops, requiring constant tinkering to match the evaporation rate. It also appeared the sap was mixing and the gradient was spread out more than I expected (front three channels were the same temp). And I do not want to be making syrup in the middle of the pan. When I flooded it, the channels had different temps indicating the difference in gradient.

Maybe it was just me, but does it really make a difference? It didn’t affect the boil rate, every half hour I was putting in 6+ gallons. It actually helped with the draw off, as it seemed to push the syrup out before it mixed with the incoming from the previous channel dropping the temp back down.

Couple comments on the build. I had some 1/8” plate and used it for the fire box because I didn’t plan on insulating it beyond a full brick (2.5”). That worked out well; however, I used 16ga on the ash box with no insulation. That didn’t work out so well. I have a bubble on the three sides (not the ash door) up toward the top. But the grate held up well, 3/16 angle with the point down. Entire bottom of fire box is grate.

884088418842

optionguru
02-23-2014, 07:57 AM
Looks great. I like the skids, I could have used those yesterday after my backhoe broke and we had to move the evaporator 75 feet across gravel. Have a great season.

Maplesapper
02-23-2014, 08:15 AM
How did you adhere the firebricks to the sides of you evaporator?

I can see that mortar is used between the bricks.
What prevents the bricks from pulling away from the vertical sides once the metal gets hot or they accidentally get bumped during loading between firings?

hodorskib
02-23-2014, 04:16 PM
Nice job looks good. I would definitely consider putting a hump in the back (the first year I built mine I used left over firebricks and stacked them up - it will make a difference in the back of the pan). If you ever add a preheater I think you will be able to adjust your flow easier and find that happy medium for adding and pushing the sugar to the front. Good luck and enjoy your hard work.

Errin OH
02-23-2014, 04:37 PM
How did you adhere the firebricks to the sides of you evaporator?

I can see that mortar is used between the bricks.
What prevents the bricks from pulling away from the vertical sides once the metal gets hot or they accidentally get bumped during loading between firings?

Maplesapper

Refactory cement sticks to clean metal as good as it does the brick. Not to be confused with mortar, Mortar is more a filler to fill gaps and used on brick to brick applications. When installing the brick dip it in a bucket of water to wet the brick, shake off the excess, and apply a thin layer of cement. It will stick right to the metal. Applied to a dry brick it will peel off and not stick to the brick. I used it for the joints as well. Cement should not be more than 1/8" thick when applied.

That said, I do not know how it will take to expansion and contraction of the metal. I would assume it wouldl break the bond, however with all the brick and cement in place it should not fall out unless you knock things around or hammerit when adding wood.

Maplesapper
02-23-2014, 08:28 PM
Thank you kindly Errin