Pondering forced draft

[abbott]

This will be my third year making syrup on a 2 1/2 x 8. I'll be maxed out this year with about 500 taps on vacuum. For next year i've been tossing around the idea of learning to weld and building an arch with forced draft. I've read through old posts on the subject and here's what i'm thinking.

Follow 802maple's suggestions as far as using a high pressure blower, 1/2" nozzles, and about 75% of the air above the fire. But here's where i want to try something a little different. Put half of the nozzles on each side of the evaporator (none front and back) On one side the nozzles go just below the pan and point straight across the arch. On the other side they are a couple inches lower and point slightly down toward the fire. Fire grates would be made out of fire brick with holes drilled in them.

Rather than simply creating turbulence i would hope to create a swirling effect in the firebox. The gasses would swirl until they were nearly all burned. By damping the stack and/or the under-fire air I would control how quickly the swirling gasses left the firebox.

Any thoughts/suggestions? Hopefully I'll have a killer design come summer.

[802maple]

My opinion is that you would still need the front air, this is where some of the guys with the new Force 5 could chime in, as what you are describing is basically that. I would go with the smaller 3/8 ths pipe though for nozzles. and I would keep just as many nozzle if not more to accomplish the higher amount of air to the top of the fire. It is being found that the smaller nozzles create better turbulence.

[abbott]

So the Force 5 has air from the front and sides. Does it have air blowing down from the back of the firebox as well?

[802maple]

I believe so But I will leave that to the new owners of the force 5

[Gary R]

I looked at Dave Y's force 5. It has air coming from the sides, front, back and below. I wish I had taken pictures inside the entire fire box. Dave, it's not too late! No ashes yet. There is also a large "V" on the ramp going to the flue area. This helps distribute the heat to the outside of the pans. Final exit of flue heat is forced up to the pan. I think accurate damper controls to all area's are key to proper burn.

It's an awesome looking machine.