Preheater hood on 2x4

[gmc8757]

Hey Guys, I'm looking to throw together a hood and preheater for my 2x4. It's one flat pan. Does it make sense to make a 2x3 hood and leave 1 foot open in the front where the draw off is? My goal is to preheat.

My other question is about condensation. I get the general idea of building the hood a touch bigger and with gutters to redirect the water. But what about the copper piping inside? How does that not cause condensation to drip back? I've seen people post about condensation trays, but not really sure how that works. Is everything sloped toward one of the gutters?

[Pibster]

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I built a 3' hood for my 4' pan. I wanted to be able to see the "almost" syrup. My preheater is based on the attached picture. Each copper pipe has its own gutter, all of which slope toward a larger gutter at the bottom. The hood is the same width as the pan. There is a gutter around the perimeter and a drain in one corner. Works great at preheating the cold sap and keeping the shack free of steam.

[gmc8757]

That's awesome, Thank you for the reply and pictures.
How hot do you think you are getting the sap?
My pan is one 2x4 pan with no separation. I could be wrong, but does the smoky lake hybrid pan have a divider from the flue section to the syrup section? So your hood sits on that divider in the front I'm guessing. How would I do it without that divider? Do I keep the front of the hood open, or do I use one sheet for the front with a small V on the bottom of it to catch water. Keep one side higher than the other. Like the redline in the picture11626

[Pibster]

My sap is coming out of the preheater around 170 degrees. The Smoky Lake pan does have a divider between the drop flues and front. My steam hood ends about 4" in front of that divider so it's not an airtight fit. I had the hood before the Hybrid pan or I would have made the hood longer to cover the first half of the syrup pan.
The hood will need 4 sides to create enough heat to warm the sap. I would run the copper pipes the long way, better heat transfer. Keep your hood level and make large gutters to catch the water with one hole in the corner for a drain. You can hang the preheater inside the hood with straps. Another option would be to mount the preheater on top of your pan with the hood separate like the attached picture.11629

[gmc8757]

170 is great, I would be very happy with that.
Do you get any water dripping back in at all?
I understand the gutter system for the hood, but I'm struggling with the gutter system for the pipes unfortunately.
It looks like that picture has a pan underneath the pipes. I'm guessing that pan would be sloped long ways to another gutter that goes side to side. Then that gutter is sloped to another side that empty's into the hood gutter?
Thanks again for your reply. I really appreciate it.

[Pibster]

I probably get a few drips here and there. I wish I had made my gutters deeper, mine are only 1/2" deep but 1" would be better. My first preheater had a large pan underneath which worked well but not as good as individual gutters. The gutters were easy to make, I just used aluminium coil stock cut into 4" strips and bent to form a V. Rivets hold everything together.

[Pibster]

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[Pibster]

This is the design I based my preheater on.

[gmc8757]

That's excellent, thank you very much for taking the time to help me understand this. I think I'll be giving it a shot in the next month or so.

[gmc8757]

How crazy would it be to use a high temp plexiglass as a window on the hood? I know the water would build up and you may not be able to see anything, but just thought maybe that would be cool.

[bahboil]

I put together a preheater very similar on my 2x4 and it brings the sap from 36 to 150' s deg. As mentioned earlier I also made 1/2" channels and wish they were 1". I made my v channels out of 1/2" aluminum angles. I figure I gained about 3-4 gallons an hour with good and preheater