New hood and pre heater

[Wanabe1972]

I have a 2x6 drop flue pan set with a 4 foot flue and 2 foot syrup pan. I just traded 1 gallon of syrup and 2 pounds of cream for 3 4x10 sheets of 24 gauge ss and am going to build hoods and steam stacks for my pans. I also have about 80 feet of rigid 3/4 copper and a good supply of elbows and tees. Here's where the questions start. Should the pre heater be continuous flow or several pipes in parallel? How much pipe should be used for a 4 foot pan? What size steam stacks do I need and should I use 1 or 2 or a 2 into one system? My brake will do 52 inches so I would make my flue hood and syrup pan hoods separately. I will have a drip rail on both hoods and a pan under the pre heater.

[MT Pockets Producer]

http://mapletrader.com/community/showthread.php?24977-Steam-hood&highlight=Homemade+hood
The above link is from a previous thread about hoods. Post 10 is a picture of our set up with an explanation of how we set it up. I think a continuous flow system would tend to get air bound so a manifold setup may be better IMO. We don't have a front hood but wish we did. Most guys I have talked to are getting 180-190 degree sap out of the preheater and we are at about 180 with the four pipes. May be able to get a few degrees higher with a couple of more if you can fit them in there some how. We really like the large doors, makes it very nice for cleaning. Don't forget to incorporate a way to drain the preheater. We put a valve on the lower manifold that dumps into the pan during freezing temps.

[VTnewguy]

To get the higher temperatures coming out of the pre heater you might want to consider adding a damper in the steam hood to hold some heat.

[Wanabe1972]

http://mapletrader.com/community/showthread.php?24977-Steam-hood&highlight=Homemade+hood
The above link is from a previous thread about hoods. Post 10 is a picture of our set up with an explanation of how we set it up. I think a continuous flow system would tend to get air bound so a manifold setup may be better IMO. We don't have a front hood but wish we did. Most guys I have talked to are getting 180-190 degree sap out of the preheater and we are at about 180 with the four pipes. May be able to get a few degrees higher with a couple of more if you can fit them in there some how. We really like the large doors, makes it very nice for cleaning. Don't forget to incorporate a way to drain the preheater. We put a valve on the lower manifold that dumps into the pan during freezing temps.

The hood looks great! I do like the full size doors as I clean my pan several times a year and this would give good access. I'm going to put one over the syrup pan to so my design would be a little different so I would have a foot or so between top of syrup pan and bottom of the hood.

[Maplebrook]

Here's a picture of my preheater. 3/4" manifolds with 1/2" copper soldered into holes drilled in the 3/4. This way saved a lot of tees and made it much more compact. Use 1/2" for your heater pipes. 3/4" puts way too much cold sap inside the hood and won't heat it well.

I built mine so I could bypass the preheater and flow sap straight to the float box. When the tank level got low, there wasn't enough head pressure to push the last of the sap uphill through the preheater. Also, when washing tanks, I'd bypass the preheater, plug the flue pan and open the valve in the bottom of the float box to drain.

Vents have been discussed at length in other threads on here. On steam preheaters, a vent from the top manifold to the float box is all that's needed to "purge" the preheater occasionally when in use.

Have fun,



16485

[maple flats]

Vents are optional if designed so that the bottom of the head tank is at least 12" above the highest point on the preheater. I designed my preheater with 4 vents, one at the corners of the high points of both levels. Then when I connected it, everything flowed well without venting. Then I opened each vent one at a time to verify and I only got sap out the vents. In the years since I have never needed to vent it. My head tank is only 12" above the highest point in the 2 tier preheater. Would less work? I don't know, but 12" does work.