Would it work ?

[getting started]

Looking for a cheap way to preheat my sap , was going to wrap 40 ft of 1/2 inch copper tubing around my smoke stack,hooked up to a small circulator pump , i have a 160 gal stainless tank feeding my rig ,was going to pump it back into it. Would this work ?

[cpmaple]

It would work but, if you dont boil all of it off that day your taking a big chance that it will spoil.why not just do the copper and value it on the bottom end so you can control the flow going into your pan just be careful you dont burn it inside the copper piping. cpmaple

[S Culver]

Yes. This is a common way results are mixed , outside/inside, wraped with an insulator. Try two valves one at the flue pan so you can hold the sap n the coil for longer and one just outside the tank so you can open the bottom and control the sap from the tank and not boil the sap in the heater if you are doing things. ( start up shut down, etc.)

Good luck

[Maplebrook]

I made a preheater like this for my old homemade evaporator. I wrapped 2 - 25' lengths of 3/8" copper tubing around the stack.
Things I learned:
1) as the tubing is in direct contact with the pipe, which is in direct contact with fire, sap will boil inside it if sap does not constantly flow.
2) don't vent it or when it does boil it spews out the vent.
3) wrapping copper tubing tight around 8" pipe requires more hands than my two, my wifes 2, and my sons 2. (solution - wrap it around 7", then spring it to fit the 8")
4)it is an economical way to preheat sap!
Ifn' I was you, I wouldn't bother to circulate warm sap back into the feed tank. As cp has said, valve it at the bottom and let it flow into the pan.
I've attached a picture of my old one.
Darren

[peacemaker]

what we did was started low and wrapped up and back into the tank just put a smaller head tank so u know u will use it all one night
and let it circulate

[lpakiz]

I recommend (if you need more heat) that after you wrap the tubing around the pipe that you insulate it also ...

[vtjeeper]

I used 3/8 copper last year the same way, wrapped around my 8 inch stack on the outside with fiberglass insulation over it and an extra piece of flue pipe around that. I started out with around 25 feet of it and it didn't warm it up all that much, I added another 25 feet or so and then it still wasn't warm but then my flow coming out couldn't keep up with my boil rate. 2x6 flat pan on cement blocks. this year I am going back to the original 25 feet or so and putting it inside the stack. I have a valve at the feed tank and one on the end of the pipe just before it dumps into the pan. good luck

[maple flats]

Johnny Cuervo made a fantastic preheater with the ability to regulate the temperature. Check out this link: http://flickr.com/photos/57535094@N0...7601539320490/ Oops, read on and follow link at post #11, sorry, error.

[WESTVIRGINIAMAPLER]

Dave,

Looks like link you posted is not any good??

[sticbow]

Try to slip the coil over the stack section it is going to be placed on. Just open the coil up enough to make it fit and slip it down. It will slip on hard and you need to be patient, but it will go!! The nice tight fit makes the copper look like it grew there.
Insulating the copper is the key to getting high temperatures. I wrap the copper with roof flashing and finish it off with some pan gasket. Now your talking about some seriously preheated sap. Put a valve on the end and let her trickle in.
The problem is getting the trickle right so you dont have vapor lock situations. I will be adding a vent to mine this year.

[buck3m]

Johnny Cuervo made a fantastic preheater with the ability to regulate the temperature. Check out this link: http://flickr.com/photos/57535094@N0...7601539320490/

http://www.flickr.com/photos/57535094@N00/1168552077/in/set-72157601539320490/

[WESTVIRGINIAMAPLER]

Years ago on the last flat pan I had it was a 3x7 stainless pan and I ran a piece of 1/2 copper tubing from the feed tank just behind the pan thru the entire arch/firebox and brought it out right next to the front on the left side of the pan. I had a quick connect on the tubing where it came out of the feed tank and the sap would jump into the pan. I brought the tubing up the side of the pan and over the lip and bent it downwards towards the sap. Never scorched any syrup at all and was batch boiling it and one time I boiled sap in it 3 or 4 days before taking any of it off to finish and it was about the lightest syrup I have ever seen. Needless to say, the sap was evaporating in the copper line as steam came out of the pipe and the sap was boiling. Never scorched anything inside the line and it was a cheap and extremely effective preheater. At the end of the night, I would unhook it at the quick connect and pour a quart of water thru the pipe. Yes, I had to evaporate off an extra quart of water which was about an extra 30 seconds of boiling and this flushed all the sap out of the line so nothing scorched inside it. It was very safe and would have been impossible for someone to have gotten burned.