Working on preheater idea

[Bernie/MA]

I'm trying to design a spiral trough for the stack for the sap to trickle down for preheat. Working on tooling for my press.

[TuckerMike]

I thought of doing this myself, but there's no way to control the heat input and I was afraid the sap would end up flashing off before it hit the preheater tank. I ended up going with 3 passes of 1/2" copper (on the outlet of the preheater tank) running through in the flue box. As long as I keep flow through it to the pan it doesn't flash and I get great preheat. I'm still in the R&D phase of this, but so far I like what I've seen.

[Bernie/MA]

I've finished the tooling and made a few sections. I don't have much heat in my shop and my hands are real sensitive to cold but as soon as it warms above freezing I'll make enough to wrap a 2 foot section of 6" stovepipe, about 12 feet of spiral trough. I can then test it with a friend's small rig. Would seem if there is enough flow it couldn't flash off and my prototype will take a cup in 15 seconds, about 15 gallons an hour (if my math is right).