soft copper tubing preheater

[berkshires]

but the end of the night was a hassle having to fill my preheater feed tank with water and letting it run into a separate bucket.

Attachment 14778

I'm also curious about this part. What would happen if you just ran a little water through, closed the valve at the end (so the pipe is full of water), and walk away while the fire in your evaporator burns out? Would the water in the pipe boil off and leave you with a burnt pipe? So do you need to babysit it and keep the water running through it until the stove (and stovepipe) cools down?

GO

[RigaudBeach]

I just made one today for my homemade evaporator. Water comes out a little warmer, but what make it efficient for me is the fact that it never stops boiling and I can control the flow rate.20170326_134127[1].jpg

[Sinzibuckwud]

I run my 3/8 line into my flat pan. Two trips around the pan and I cannot touch the sap coming out. By heating with the boiling liquid I never have to worry about scorching.

[bowhunter]

That's really and excellent idea.

[Trapper2]

I run my 3/8 line into my flat pan. Two trips around the pan and I cannot touch the sap coming out. By heating with the boiling liquid I never have to worry about scorching.

Picture please?

[RileySugarbush]

I run my 3/8 line into my flat pan. Two trips around the pan and I cannot touch the sap coming out. By heating with the boiling liquid I never have to worry about scorching.

If I am understanding this correctly, you are running the tubing down through your boiling sap and back out, you are not really helping yourself much. The gain from a preheater is that the incoming sap is heated with waste heat, best from condensing water vapor over the sap pan in a hood and collecting the condensate so it doesn't drip back into the sap. Alternatively, from the waste heat in the stack, though that is touchy since the temperature can go very high and burn your sap in the tube of boil it and squirt hot sap all over someone.

If you are preheating using the boiling sap, you pay as much as you gain since the heat going into your feed sap comes from the existing sap.

[lyford]

I was thinking the same as RileySugarBush

[Sinzibuckwud]

If I am understanding this correctly, you are running the tubing down through your boiling sap and back out, you are not really helping yourself much. The gain from a preheater is that the incoming sap is heated with waste heat, best from condensing water vapor over the sap pan in a hood and collecting the condensate so it doesn't drip back into the sap. Alternatively, from the waste heat in the stack, though that is touchy since the temperature can go very high and burn your sap in the tube of boil it and squirt hot sap all over someone.

If you are preheating using the boiling sap, you pay as much as you gain since the heat going into your feed sap comes from the existing sap.

I see what your saying, and agree. Guess I never thought about it that way.
Better than dumping in cold sap, which was my alternative, this system runs itself once boiling and does save time adding cold sap slowly or losing the boil adding lots of cold sap at once. If the boil dies so does the pre heater, boil comes up sap comes out....after some fine tuning of course. Spent all my money on a woodlot so the other end is still pretty primitive, we'll get there....eventually.
I have a new stove this year and will have a stock pot over the existing top vent with direct heat more along the lines of those half pint setups, just made out of stuff around here.
Eta: Found a video on the boys phone sort of showing the setup.https://youtu.be/zaE0feIDCKU

[Johnny Yooper]

Anyone ever tried using soft copper pipe wrapped around the flue pipe as a pre-heater? I'd have some kind of little pot or tank soldered in at the top end, then the sap would flow through the copper tubing, with a number of wraps around the flue pipe, and a valve at the bottom end. Seems like all that copper in close proximity to the hot flue pipe would heat the sap really fast.

GO

I made a copper tubing preheater several years ago, wrapped tight around my chimney pipe, I pump 40f sap from an outdoor tank to the top of the tubing, spirals down and exits through a gate valve into one of my pans, checked the sap coming out of the tubing with an accurate hand held multimeter with thermocouple attachment, it read 160F; I have a gate valve on the output to adjust the delivery rate of hot sap into the pan. Prior to shutting down, I switch to water as it's a nice way to get hot water in the shack for cleaning up. I like to try something new each season simply to learn and try to make things more efficient, I might add a second copper coil to the stack this year so see if I can increase the temperature of the sap going into the pan.