High Efficiency arches

[theguywiththename]

Somebody mind explaining these arches to me. I understand the idea more or less with the block and fire tubes but lack why not just leave it a block so the gases have to go up? Also where do the fans normally sit on these? I haven't much Experience in person with these arches. I might be building a 2x8 here this off season and am considering many things.

[Flat Lander Sugaring]

sorry its early but "block and fire tubes"?

high pressure fan goes outside or another room so you dont have to listen to it, then gets piped into arch. split tube from fan and one tubes goes to fire under fire one goes to fire above along the rails at front of flue pan and some have it in the door.

[maple flats]

Actually, mine splits, but in the original published plans it only goes over the fire. Use this link http://www.uvm.edu/~pmrc/Combustion.pdf It gives all of the information. I did split my high pressure (HP) air into an air under fire (AUF) and an air over fire (AOF) by using a Y fitting in the 4" PVC pipe coming in under the arch into 2 PVC 3" pipes, each with a ball valve to balance the flows. You can read back thru my project if you want. If I were to do it again, I think the only thing I might change, is to place my HP blower farther from the sugarhouse. I have mine just 3' from the sugarhouse wall, under my head tank and now I need to listen to it all thru each boil. They are loud, in fact mine might be extra loud because it it belt drive using one of those adjustable length belts (that is the only way to get a belt on mine, unless the entire motor mount is dis-assembled) and the driven pulley is removed and slid back on with the belt on it. They are a loud type of blower, but for a blower, they push more pressure. A HP blower is high pressure, not high CFM (cubic feet per minute). Mine made the fire burn hotter, the boil faster all while using about 35% less wood, just by putting HP air in over the fire to get far better burn of the wood gases that would have run out of oxygen and gone unburned until the "smoke" exits the stack. My stack temperature is actually lower while boiling harder, just by using the heat sooner under the pans.