Anyone with a half-pint

[Jim Schumacher]

Could someone please let me know what the exact dimensions are for the factory preheater pan on a half-pint? Also, a breif description of how the stainless sheet is contoured on the top(turned in, turned out, hemmed, ect) Thanks a ton!

Jim

[WESTVIRGINIAMAPLER]

Here's a good picture of it. I think preheater pan is 8 x 24 as the main pan is 33 x 24.

http://www.leaderevaporator.com/pdf_files/half-pint-evaporator.pdf

[Brent]

I'm guessing you're thinking of making your own preheater. If that's the case, try to work up a design that will extend slightly over each side with a slope down and outward ... sort of like a 28" wide shallow "w"

The preheater that Leader offers does very little to warm sap and it does a great job of dribbling 1/4 of the steam back into the pan when it condenses. It should really have more surface exposed to the steam to be effective and then
have a way to get rid of the condensation. I was patently unimpressed with it when we had a Half Pint

[Jim Schumacher]

To be honest I don't believe in a preheater pan at all. I never used one so correct me if I am wrong. It seems to me that the steam will simply condensate when it contacts the pan full of cold incoming sap and drip back into the boiling pan, warranting the need to be re-evaporated. The only reason I asked is because it was requested of me to build a pan exactly like that of the half-pint preheater. I offer my point of view to all of my customers, but it is only my point of view.

[Flat Lander Sugaring]

Quoted from UVM proctor Maple Research


Condensate is yet another factor
that affects efficient operations of the
preheater. For every 980 BTU's of energy
transfer from steam to sap, a pound of
condensate collects on the tube bundle.
If the condensate is permitted to drip
back into the pans, direct heat from the
oil burner must re-evaporate this water.
If this occurs, the preheater's
efficiency is significantly reduced. The
condensate must be collected in a drip
pan as shown in Fig. 2 and taken out of
the hood by a tube. This condensate can
be used as hot water for cleaning or
other purposes.


here is the link

www.uvm.edu/~uvmaple/sappreheaters.pdf

I have heard some people say it could also give an off flavor to the syrup by letting the condensate drip back in

[WESTVIRGINIAMAPLER]

It's more of a feed pan than a preheater. I thought the same thing that it wasn't helping hardly any but it might give you a slight gain. Be nice to see someone do a test on 2 of them sitting side by side in a controlled enviroment.

[BoarsNest]

I'm building a preheater pan that is going to fit on a raised stack box. It's going to be shaped around my stack and not hang over my pan at all. I hope to have it done this week and try it next weekend. I'll let you know if that works any better than a preheater that sits over the sap pan.

[Farmboy]

Last year I had a half point pan on a barrel. The pan did warm the sap to 100-125 degrees. Thad an improvement over 40 degrees. I think it would work better if it is closer to the stack and not over the pan. I think it was the stack not the steam that heated the sap. I had single wall pipe and ran it wide open so it was pretty hot behind the evaporator.

[WESTVIRGINIAMAPLER]

Could you push it up against the stack?

[Brent]

If you push it to the stack, as the level goes down the scum line gets backed on nearest the stack.

[BoarsNest]

With the way my stack box is designed, I burnt the back of my pan at the top of the sap level. I am going to put insulation between the stack box and the pan this year. With the new preheater I am going to insulate between the stack and the preheat pan as well. Last year the stack box was glowing red so I am hoping that with the preheater sitting on top of the stack box it will transfer enough heat to get my temp up a lot.