Exhaust Fans

[DavyJones]

Hi everyone. I am going to start to build an exhaust hood pretty soon, only a couple short months for me for tap time, and I have been looking arouns but don't really know how I am going to power this thing. I looked on Northern tool for exhaust fans and didn't see anything except big expnsive ones. I was thinking that there would be some type or round 6" inline thing that would connect inside my exhaust duct work. Am I completely stupid on this? Is there some other way to power a hood? If anyone has any links or plans for a hood or pictures I would appreciate it.

P.S. my pan is 2' x 3' that is what I was planning on making for my hood.

thanks
David

[RileySugarbush]

Unless you have unusual circumstances, you probably don't need to power it. The chimney effect of a steam stack on the hood will pull the water vapor out. I have a hood on my 2x3 sap pan with a 7" duct about 6 or 7 feet up to my cupola and it draws perfectly. If the hood doesn't sit right on the pan, you may need a bigger/longer stack to draw better.

The little inline axial fans you may be thinking of can be had at Home Depot, but probably won't survive the temperature and moisture.

[DavyJones]

Sugarbush thanks
Last year I did everything outside so things were simple. How do you move your hood away easily? I was thinking I was going have my hood a foot off my pan so I could monitor everything. I just use a simple digital thermometer to tell when I am done. I was thinking of going out the side of my shack with the stack from my hood that is why I was thinking I was going to have to power this thing. I could go out the roof. Not really sure what I should be doing here but realize without a hood I'm probably going to have a ridiculous amount of steam inside. I could just put a fan in a window and not a hood at all but since I don't have any experience with this I don't want to start to boil and find out that I should have installed the hood you know what I mean?

I know what it was like outside there was allot of steam then again there was always alittle breeze too and I was just under a little canopy to keep the rain and snow off me. It was steaming pretty good.



Unless you have unusual circumstances, you probably don't need to power it. The chimney effect of a steam stack on the hood will pull the water vapor out. I have a hood on my 2x3 sap pan with a 7" duct about 6 or 7 feet up to my cupola and it draws perfectly. If the hood doesn't sit right on the pan, you may need a bigger/longer stack to draw better.

The little inline axial fans you may be thinking of can be had at Home Depot, but probably won't survive the temperature and moisture.

[RileySugarbush]

With one pan like that, you are thinking correctly in having it raised up so you can see what is going on. I wouldn't want to have a flat pan out of sight under a hood.

My hood is on ropes so I can raise it up if needed, but I only do that to clean the pan. There are doors in the sides to get in there when needed.

I've run my 2x6 with the hood off and the cupola open and on a calm day, that works fine. 40 gallons of water per hour going right up through the roof! Trouble is, sometimes it won't work so good, and you will be fogged out.

If you can, run a big stack straight up through the roof and make a hood (wider than your pan) and up high enough that you don't knock your head on it. The higher it is, the wider in needs to be so the steam doesn't miss it. The stack will be pulling room air, so that's why you need a bigger stack, to handle the greater volume.

Chimneys work because they have a long column of air that is warmer than the surrounding air and therefore lighter, so it rises and sets up a nice draft. Longer columns work better than shorter ones. Vertical works and horizontal doesn't.

So if you move the hood up too high, then your stack length is short and it won't draw well. You are back to an open room and a cupola!

I think others here have just used cheap room air fans in ridge vents with some success.

[Gary R]

Davy,

look at my thread. you'll see last year's hood and this year's hood. Lot's of other threads to look at that have all shapes and sizes. Last year's sat on arm's to hold it of the pan. It worked great. no steam in shack at all. I built a new one because of a bigger pan I made. I used aluminum this year to make it lighter. I've seen other's that use gal. sheet metal. That would be cheaper and probably not too heavy. As Riley said, if you go straight up it should draw steam with no power. If you go sideway's you may have constant drip in sugar house. My stack is supported at the roof. I have a pipe coupler called a draw band that connects the pipe. They are easy to remove then your hood will come right off.

[DavyJones]

Thanks, Gary were is your thread?
David


Davy,

look at my thread. you'll see last year's hood and this year's hood. Lot's of other threads to look at that have all shapes and sizes. Last year's sat on arm's to hold it of the pan. It worked great. no steam in shack at all. I built a new one because of a bigger pan I made. I used aluminum this year to make it lighter. I've seen other's that use gal. sheet metal. That would be cheaper and probably not too heavy. As Riley said, if you go straight up it should draw steam with no power. If you go sideway's you may have constant drip in sugar house. My stack is supported at the roof. I have a pipe coupler called a draw band that connects the pipe. They are easy to remove then your hood will come right off.

[Gary R]

New guy's rig, Homemade equipment.

[Haynes Forest Products]

You can get the in line fans at Granger but save your money steam is generated faster than the fan can move it so you end up causing a problem not solving it. Your evaporator with a steam hood is a realy crappy steam engine so with that in mind big long stack and viewing space on the sides and the steam will move out fast. I have a friend that boils on a 3x10 that has a hood that is tight on all sides of the flue pan and it get so dang hot in the shack that you cant stand it. With a open area on the syrup side the heat gets sucked out of the evaporator room.

[peacemaker]

why not go to home depot and buy there cheapeast stainless range hood with exhaust atleast its a sealed motor designed to exhaust stem ...

[RileySugarbush]

I don't think a cheap range hood could keep up. And where would you put it?

[peacemaker]

why couldnt u do the same as pulleys and rope

[RileySugarbush]

I suppose that would work if the fan had enough capacity. You're right, it should hold up fine.