Flexible copper tube pre-heater

[OneLegJohn]

Any one try to wrap felexible copper tube around the stack before bringing the sap to the float valve? There has to be a quick simple way to exchange heat from the stack to the incoming sap... I have a 3/4" line coming from my storage tank - flexible copper around the stack is all I can think of.

[Jay]

OLJ,I think if you do a search you will find some info on it, I think a few guys said that it was hard to control the temp in the stack and the sap was getting to done? Look at Johnny Cuervo's pictures I think he has a set up like that, good luck. Jay

[Jim Brown]

We tried it last year with soft copper and found that you can't bend it tight enough to get it close to the stack for the heat tranfer. I built a small box out of tin and enclosed the tubing the problem was that the sap would boil in the tubing before it got to the float valve. Now we had a vapor lock problem. we took it off. hope you have better luck!
Jim

[royalmaple]

Onelegjohn-

Go down a couple of questions to the homemade evap question, and click the link to westvirginiamaple, brandon has a nice copper tubing preheater design, I think from the looks it is 3/4 tubing as well, so you can tie right into your existing feed, then out to float box.

I am working on a similar one currently.

[OneLegJohn]

How about boiling water and running the line through heated water - or super heated water? I guess the water would heat the pipe - but not to a boil.


If we had free gas - I would put one of those inline tank-less heaters in. C'mon gas company - drill that well!

[royalmaple]

OLJ-

If you do brandons design and put over your first pan or any pan, the steam is heating the pipe for free, nothing else to boil or frig with.

Even if you didn't have a hood, it would still be better than cold sap coming in. Steam is 500+ degrees.

[maple flats]

How do you get the 500+ degrees. My understanding is that unpressurized steam is barely over 212, correct me if I am wrong. Now, under pressure it sure is possible but I am not sure what sort of pressure it would take.

[royalmaple]

Maple flats, you are correct. Good catch. I was thinking of a different steam application which did involve pressure. Normal steam under 0 PSI is 212 degrees, I am pretty sure it would be about 250 - 275 PSI to get up to about 500 degrees. I could still be off a bit.

I don't think the typical evaporator hood is designed to increase/create pressure to those levels, if so you better make sure you are using more than pop rivets to hold it on.
:lol:
:!:
I guess that is enough physics for sunday night....

[saphappy]

I have a 2x6 wood fired normal draft with 3' flue pan and 3' syrup pan. I had a 1/2" felx copper with 5' loop under sap pan. That preheated a little but not enough. I then went with a 5/8" diameter flex copper with about 12' looped under the sap pan (I run it in and out of the arch under the stack , drilled holes). That works great, only a couple of times running it does it vaporize inside the tubing, and it produces sap right near boiling temp to keep that sap pan a rolling boil. I rigged it so the valve to start the sap into the sap pan is at the lowest point (under tanks and flex copper line) and has a drain in it. This rig enables me to drain after the arch has cooled so if the sap freezes the tubing would not rupture . the flex coil has a consistant rise from the valve to the sap pan so any vaporization inside tubing will force sap into pan, not back into tank.

This works pretty good, but highly sensitive to diameter of flex tubing and length under the sap pan. If I were to do it again for another arch I would start with a little under sap pan and increase the length under the pan by coiling until I got hot, but not boiling sap.

Not bas for $50 in supplies

[saphappy]

I have a 2x6 wood fired normal draft with 3' flue pan and 3' syrup pan. I had a 1/2" felx copper with 5' loop under sap pan. That preheated a little but not enough. I then went with a 5/8" diameter flex copper with about 12' looped under the sap pan (I run it in and out of the arch under the stack , drilled holes). That works great, only a couple of times running it does it vaporize inside the tubing, and it produces sap right near boiling temp to keep that sap pan a rolling boil. I rigged it so the valve to start the sap into the sap pan is at the lowest point (under tanks and flex copper line) and has a drain in it. This rig enables me to drain after the arch has cooled so if the sap freezes the tubing would not rupture . the flex coil has a consistant rise from the valve to the sap pan so any vaporization inside tubing will force sap into pan, not back into tank.

This works pretty good, but highly sensitive to diameter of flex tubing and length under the sap pan. If I were to do it again for another arch I would start with a little under sap pan and increase the length under the pan by coiling until I got hot, but not boiling sap.

Not bad for $50 in supplies

[Maple Hill Sugarhouse]

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[brookledge]

Its no different than a pressure cooker for your stove, the weight on top can add different amounts of pressure to raise the steam temp.
Keith

[Maple Hill Sugarhouse]

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