Errin OH
02-22-2014, 10:33 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
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