Vent hood ideas

[catfisher]

Third year at this and we're moving our homemade evaporator we built last year inside an old 16' x 24' garage that has no windows for cross ventilation. The evaporator's a fuel oil tank cut down, insulated on the bottom with sand and lined with fire bricks. we're cooking with a 2'x4'x8" pan and adding a 26"x12"x6" warming pan that sits on top of the main pan

Looking for ideas for an inexpensive vent hood that we can use for at least this year if not longer. Priced a fabricated SS vent hood and its a little more than I want to spend this year. Thought about cutting a food grade 55 gal drum in half lengthwise and piping it in the center up and out.

Not looking for something tight fitting unless it makes sense, just want to be able to lower it over the pan fairly close and draw the majority of the steam out of the building... FYI, not adverse to putting some holes / vents in the walls if that's a good way to go.

[jmayerl]

Cheapest would probably be a plastic vynal with pvc frame, next cheapest would be to fab up a aluminum one and pop rivet it together. A 4x8 sheet can be bought for about $40. Vent it straight up through the roof since that is the natural way steam wants to move, do fight it.

[tcross]

a plastic hood will work for a year or two. I currently use one. framed it out of strapping and wrapped it in plastic. I have to vent mine out the side wall right now (will be through the roof in a few years). I have a hole in the wall that fits a 20" box fan nicely... that is what shoots the steam out of my shack. works good!

[BreezyHill]

Not looking for something tight fitting unless it makes sense, just want to be able to lower it over the pan fairly close and draw the majority of the steam out of the building... FYI, not adverse to putting some holes / vents in the walls if that's a good way to go.

For the flue pan our current hood is made of SS flashing that came in 24" rolls. In the hood dad made a removable cover to see the boiling sap. it vents out the back of the hood on the long side and directly over the float box. The head tank was plumbed thru a 2" copper tube with a pvc transition to turn and attaché to the head tank. Two seasons ago I got the preheater to hot and warped the pvc. Now it is SS milk line to the head tank valve.
10578 The front hood was a ply wood box to catch the steam and run it out a 8" pipe. The room was pressurized by a 36' farm fan. This forced the air out thru the steam vents.

Last season we remodeled an added a metal ceiling and enclosed lights and added the SS to the preheater. Now the steam is sucked out of the hoods by way of a Chicago fan. The idea was that pressurizing the room was reducing the boiling rate. I think it made a small difference but not as much as I was hoping for. 1057910580
The dark wood was before the remodel and the white is new wood and painted.
Sap in the tank is usually in the low 30's and is around 185-190 coming out of the preheater.

Remember watched pot never boils...cover the flue pan tight and you will get a better boil rate by keeping the heat in.

Good Luck!

Ben

[maple flats]

My first 3 hoods (3 different evaporators) were all made out of sheet aluminum and were pop riveted. I shaped them on an aluminum trim brake but you could also do it using 2x4's and clamps. My current one is SS and factory made, but it was a very slightly damaged one at the factory, and they hit me less than half price of what they had quoted me for a new one a few weeks earlier.
If at all possible, vent thru the roof, if not, go out as high as you can in the wall.
I went on a maple tour years ago, and at one sugarhouse (who's syrup placed 1st at the NYS Fair) used poly sheeting, attached to a frame of firing strip lumber.

[catfisher]

Thanks for the ideas.

I have a couple of weeks to get this done, will let you know how it turns out.