Copper tubing pre-heater modification

[Maplesedge]

Want to try copper tubing to pre-heat, but avoid boiling sap in the tubing or scorching the inside when the sap runs out.

Thinking of bending the tubing in a C or horseshoe shape so I can get it around the stack or remove it when I want.

That also allows me to squeeze it tight against the stack when I want more heat, or loosen it an inch or so away so it absorbs less heat when the fire is really hot.

Also, might play with the number of loops in the tubing, say 2 or 3 on each side. The sap flow wont be that fast, so less loops of copper will impart less heat to the sap while it's flowing through.

Want to end up with almost, but not boiling, sap flowing into the pan.

[Maplesedge]

Well, that didn't work! Ended up re-bending the tubing around the stack mid-boil. Just not enough heat getting into the sap. Was still only luke warm going into the pan. Sap is still icy in the bag, so that doesn't help.

Maybe should use 20' of tubing instead of 10'?
Will scorched inside of tubing be problem?

[KenWP]

The sao won't scorch inside the tubeing aslong as its full. When you run out you will burn the inside unless you run water through it to clean it out and let it sit. That or have it so the tube can run someplace else and run water through it. I run water through it after the saps done so that I have hote water for washing up.

[Willy]

This year I went to old wood stove with (2) pan setup. Last years setup, next to it was a 55-gallon barrel with (2) roaster pans. Worked well, but constantly lost boil adding somewhat preheated sap from coffee cans placed over the stovepipe.

This year I decided to use Cu tubing for preheater. I have a 6-gallon bucket setup for gravity feed, with a brass valve for regulating sap. When I got the pans boiling really good, I had a very consistent stream, not drip, into the pan keeping the level in the pan steady. Only problem, which will be fixed this weekend, is when the right pan gets low, have to open valve to refill, causing loss of boil. Will be adding a Y connector to feed both pans. Also with more output I will be making another turn around the pipe. Keeping the coils below the damper keeps all the heat around the coils. HOT coming out... real nice!!!

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[lpakiz]

Willy,
Don't be afraid to cover the coils with a tin sleeve and insulate with building insulation.

[Jerome]

Willy
Bend a copper tube in a u shape to go from one pan to the other fill it with sap when you start to boil then as the pan that does not have the sap running into it gets lower it will siphon hot sap into itself, save a lot of work, almost makes it a finishing pan,

[Maplesedge]

Willy, that's a nice looking rig, hope you get good results.

The pic below is from my first boil, when I re-bent the tubing around the stack mid-boil, so it looks sloppy. But my second boil, I re-wrapped it tighter and it puts out hot sap as long as I can keep the fire roaring. Should probably go to a 20' length tube from this 10 footer, but I'm too cheap to blow another $20 when this season could be pretty much over already anyway.

I just blow it out when I'm out of sap and I can't taste any difference if it's scorching inside or not, so I guess it's not a problem for me.

I do like it better than my old coffee can over the pan pre-heater from last year, kinda looks like a fountain.

[elmcreekmaple]

Willy, that's a nice looking rig, hope you get good results.

The pic below is from my first boil, when I re-bent the tubing around the stack mid-boil, so it looks sloppy. But my second boil, I re-wrapped it tighter and it puts out hot sap as long as I can keep the fire roaring. Should probably go to a 20' length tube from this 10 footer, but I'm too cheap to blow another $20 when this season could be pretty much over already anyway.

I just blow it out when I'm out of sap and I can't taste any difference if it's scorching inside or not, so I guess it's not a problem for me.

I do like it better than my old coffee can over the pan pre-heater from last year, kinda looks like a fountain.


Here is our setup - I hope it will get hot enough. If not - we are planing on wrapping the coils with that thermal blanket that is rolled up in the evaporator in the pic - it is 3M and it didnt budge when we held a cutting torch to it.

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[KenWP]

That tubeing looks like the way mine last year looked. It worked enough to temper the sap at least. This year i wrapped the tubeing around the stack and covered it with sheat metal and it works better. Just finished adding 12 more feet of tubeing to it that I had laying around.

[Maplesedge]

Did my third boil today. Found that as long as I have a strong surging boil in the pan the sap can trickle in just warm and it won't break the boil. I just have to play with the flow rate to try to match what's evaporating out.