Preheater for Smoky Lake 2 x 4 hobby Hybrid

[devils11217]

I am looking to build a preheater for my 2 x 4 smoky lake hobby hybrid. My plan is to run 1/2" copper pipes resting on top of the evaporator in the steam up and down the pan a few times and then into the float box. It will be fed by a 330 gallon tank by gravity. I am hoping having the pipes sititng on top of the pan will give me heat from the boil and steam. Here are my questions

Does this system need to have a vent? will the steam be so hot to cook the sap in the pipe? (i dont think so since there is no direct flame contact or conduction) but i dont know..

How many times should i run this pipe up and down the evap pan? i am think 4 times and then into the float box. ( i am only looking to warm the sap to anything above 100 degrees.. i dont want to mess with have sap cooking in the pipe. anything is better than 32 degree sap.

Is my 1/2" pipe to small? it is only a 2 x 4. I think i should be fine.

[mellondome]

Where are you having the condensation from the pipes go? ( if it drips back into the pan, you will have to evaporate it again .)Will you have a hood over the pan to optimize steam contact with the preheater?

[MISugarDaddy]

When I had a 2' by 4' pan, I built a preheater using 3/4" copper pipes and aluminum angle iron that I soldered together. Condensation from the copper dripped into the aluminum angle and because the back edge was elevated, ran down to the bottom angle piece and then out the open end into a pail. With this unit, I was able to warm sap from 32 degrees to 105 degrees with out any problem. You will want to elevate your tubing to avoid a vapor lock and yes, you will need a vent that reaches higher than the top of your feed tank.
Gary1245112452

[devils11217]

Really like this design. I went with the 1/2" pipe because of cost. I hope i didnt screw myself. I think i will get adeqaute flow. Did you ever have a problem with the flow and this design.. I am assuming that plastic pipe next to the float box is where your vent was?

[MISugarDaddy]

I don't think you will have any problem using 1/2" pipe for your preheater, because that is what Jim at Smoky Lake uses. You are correct, the plastic pipe going up is 1/2" PEX tubing and is the vent. I actually ran the vent tubing back to the feed tank so if and when the sap flowed through it, it just went back into the feed tank.

[Urban Sugarmaker]

Love this design. I might have to add this next year.

[bigschuss]

When I had a 2' by 4' pan, I built a preheater using 3/4" copper pipes and aluminum angle iron that I soldered together. Condensation from the copper dripped into the aluminum angle and because the back edge was elevated, ran down to the bottom angle piece and then out the open end into a pail. With this unit, I was able to warm sap from 32 degrees to 105 degrees with out any problem. You will want to elevate your tubing to avoid a vapor lock and yes, you will need a vent that reaches higher than the top of your feed tank.
Gary1245112452


Gary, can I ask a few follow up questions? I am thinking about doing the same thing as the OP this year. The little pre-heater that came with my Mason 2x4 just isn't adequate.

The angle iron underneath the copper catches and prevents condensation from the copper from reentering the pan. Does the angle iron also not accumulate condensation?

You rig looks fairly permanent one set up for the season. Is there some kind of a quick disconnect at the top of the vertical copper feed pipe?

And lastly, is that valve at the bottom of the vertical feed pipe to drain the system?

Thanks. Think I am try to copy your design.

Blair

[Noah's Ark]

Sorry to redirect this thread but I also have a Mason 2x4 and have been trying to figure out a way to better preheat my sap. I started with the idea of wrapping around the stack but never really liked it much. I really liked this idea and I was thinking of doing 7 tubes with the last feeding the pan to the front of a channel and the last tube not being attached to the bottom manifold. The one thing holding me back is how do you scoop out any foam/scum that builds up. With my evaporator (bigschuss you will understand this I believe) I think I would have to have the front manifold on the divider walls to have a slope or have no slope. Either way condensation would not run off and I wonder if this would counter the effects of the preheater with the condensation dripping back in. How much condensation are you getting in your bucket?

Bigschuss were you planning to attach yours to the existing preheater or another way?

[Urban Sugarmaker]

Smoky Lake sells a stainless steel version of this tray. I think it's $300+ without the copper tubing setup. But, you could do it yourself. Theirs has cutouts in the V channels to allow steam to directly contact the pipes. I think I might buy one for next year. I wanted it for this year but I spent too much on the RO. I think with this tray you could make a less elaborate pipe section and save on some copper. But, it may not preheat as well. They told me without a hood, this would preheat to 190F. If that's true, you would definitely be saving energy and time. 12467

[devils11217]

I just mine today based on Gary's design. Came out Rey nice for some idiot like myself doing it. I used 1/2 pipe since it's cheaper. It cost me 120 for all supplies. 12473.this picture is not the finished verison. I will post that in a few

[MISugarDaddy]

Blair,
I had condensation form on only one piece of the aluminum angle iron, which was the 3/4" bottom piece that the other 1/2" angled pieces drained into. The reason I think this happened was that most of that piece was not over the evaporator pan so it was colder than the others. There was no condensation on the other pieces. Very little condensation formed on it, just an occasional drip on the front of the arch. I think if I had made it an inch shorter, there would have been no problem at all.
The reason for the quick disconnect and union on the preheater was so I could remove it in the spring for cleaning.
You are correct on the reason for the valve on the preheater...so I could drain the preheater when I was done boiling each day. I didn't want sap sitting in it over night.

I did want to mention that the reason I did not make the preheater cover the entire pan was so I could reach in and scoop out foam as it formed in the flue pan. However, I finally started using defoamer, and I no longer had to scoop out foam and had far better boil. I only would add two to three drops of defoamer everytime I added wood to the fire which was about every 12 minutes and there was almost no foam in the pan.

Also, Noah's Ark asked how much condensate was collected from the preheater and I would estimate that from 4 hours of running, we would get between 2 and 3 gallons.
Gary

[devils11217]

Finished it today. I think I might do a 45 vs a 90 on the fresh sap inlet but other than that I like it. Thanks gary12487

[bigschuss]

Blair,
I had condensation form on only one piece of the aluminum angle iron, which was the 3/4" bottom piece that the other 1/2" angled pieces drained into. The reason I think this happened was that most of that piece was not over the evaporator pan so it was colder than the others. There was no condensation on the other pieces. Very little condensation formed on it, just an occasional drip on the front of the arch. I think if I had made it an inch shorter, there would have been no problem at all.
The reason for the quick disconnect and union on the preheater was so I could remove it in the spring for cleaning.
You are correct on the reason for the valve on the preheater...so I could drain the preheater when I was done boiling each day. I didn't want sap sitting in it over night.

I did want to mention that the reason I did not make the preheater cover the entire pan was so I could reach in and scoop out foam as it formed in the flue pan. However, I finally started using defoamer, and I no longer had to scoop out foam and had far better boil. I only would add two to three drops of defoamer everytime I added wood to the fire which was about every 12 minutes and there was almost no foam in the pan.

Also, Noah's Ark asked how much condensate was collected from the preheater and I would estimate that from 4 hours of running, we would get between 2 and 3 gallons.
Gary

Thanks Gary. That's helpful. Appreciate you taking the time to respond.

Blair

[bigschuss]

Finished it today. I think I might do a 45 vs a 90 on the fresh sap inlet but other than that I like it. Thanks gary12487

That looks great. Did you use aluminum angle iron below the copper? I don't see a vertical vent on your unit?

[devils11217]

Yes. I used 1/2 inch angle under the pipes. Same as Gary. I haven't attached the vent pipe yet. I installed the tee for it near the float box but will attach pipe when it's in final position

[bigschuss]

Yes. I used 1/2 inch angle under the pipes. Same as Gary. I haven't attached the vent pipe yet. I installed the tee for it near the float box but will attach pipe when it's in final position

Thanks. Think I'll start building mine. Great thread!

[SDdave]

Maybe a stupid question here but, why use mostly T fittings vs using all 90 degree fittings? Maybe its Monday and my brain is still on weekend time.

SDdave

[psparr]

Maybe a stupid question here but, why use mostly T fittings vs using all 90 degree fittings? Maybe its Monday and my brain is still on weekend time.

SDdave

If you use 90s and make the sap flow through the whole pipe, you run the risk of a vapor lock. Allowing the sap to find its own route greatly eliminates that. Also the sap feed needs to be lower than the outlet for the same reason.

[TrentonMaple]

These preheaters and the pics are outstanding! You guys have inspired me and I think I know what this weekend's project is going to be.

I just upgraded to a Smoky Lake 2x4 on top of a Mason 2x4 arch. I had Jim modify the rear of the pans so the flues would clear the back due to the Mason's design. Like many of you, I did the coil wraps on the stack, but that never really worked out - it either ran to fast through the coil (cold sap) or too slowly (burnt sap).

[Urban Sugarmaker]

These preheaters and the pics are outstanding! You guys have inspired me and I think I know what this weekend's project is going to be.

I just upgraded to a Smoky Lake 2x4 on top of a Mason 2x4 arch. I had Jim modify the rear of the pans so the flues would clear the back due to the Mason's design. Like many of you, I did the coil wraps on the stack, but that never really worked out - it either ran to fast through the coil (cold sap) or too slowly (burnt sap).

Have you boiled with your new pan this year yet? I am considering upgrading to that pan next year and want some feedback please. Thanks.

[MunsterMapler]

Very nice work! I am looking into whipping one together for my 2x4 hybrid also. My dilema is that the bottom of my head tank is only about 8 inches higher than the top of my pan. Would that be enough head pressure to push that sap uphill that 4 inches or so over the 4 foot length of the pan?

[MISugarDaddy]

You shouldn't have any problem as long as the bottom of your head tank is above the highest point of the preheater. If you do experience a flow reduction it will only be when the head tank is almost empty, but you will still get flow. At that point, you would probably be letting the fire die down so it shouldn't be a problem. Even though my head tank is 8' in the air, when it got down low the flow slowed down because of the lack of pressure from the low level of sap.
Gary

[devils11217]

Second what Sugar daddy wrote.... I lost sleep over building this after my head tank level was built. I wasnt planning on building a Preheater on top of the pan and didnt account for the height increase as well as running sap up a small incline. I finally got to test this with water in the head tank the other night. My highest point on the preheater is the inlet. My head tank outlet is about 1 foot higher. There was very good flow throughout the system and i was able to sleep again..

[DoubleBrookMaple]

I just mine today based on Gary's design. Came out Rey nice for some idiot like myself doing it. I used 1/2 pipe since it's cheaper.
I eventually will make my own, and did some numbers crunching to see what the cost difference would be based on square inches of exposed copper per foot. It comes out to a wash on 1/2" vs. 3/4" pipe. It would require less 3/4" pipe and fittings, and angle material for 3/4". I think 3/4" is the way to go.
"M" (thin walled, cheaper) with better heat transfer is the way to go.
O.D. of 1/2" is .625" and 3/4" is .875"
1/2 in pipe is 23.5 sq in per ft
3/4 in pipe is 33.9 sq in per ft
HD has "M" 1/2" x 10' for $9.24 and 3/4" x 10' for $15.56

[TrentonMaple]

Have you boiled with your new pan this year yet? I am considering upgrading to that pan next year and want some feedback please. Thanks.

Not yet. The last warm spell we had I tapped my tubing mainly to flush out the lines. So I have yet to boil anything in 2016.

If you are planning on replacing your Mason pan with a Smoky Lake, it is important to let them know you have a Mason arch. The Mason has a flange all the way around the perimeter, and a Smoky Lake pan has flues that extend all the way to the rear. If there isn't a modification to the arch (extend it and remove the flange) or the new pan (step in the flues) it won't fit on. I had Jim modify my pan with a step in, but in retrospect I should have just lopped off the end of the arch, lengthened it a foot, and got a 2x5.

Here's a pic of the preheater I built from 3/4" thin walled copper pipe. I'm waiting on my float box to arrive to finish the hookup.

12952

[devils11217]

I went with 1/2" Maybe i am totally wrong on this... my thought process was yes 3/4 inch pipe as more copper surface area but also has more water in it... water sucks the life out of your heat transfer. i went with 1/2 inch copper in hopes less water equals quicker / more heat transfer



I eventually will make my own, and did some numbers crunching to see what the cost difference would be based on square inches of exposed copper per foot. It comes out to a wash on 1/2" vs. 3/4" pipe. It would require less 3/4" pipe and fittings, and angle material for 3/4". I think 3/4" is the way to go.
"M" (thin walled, cheaper) with better heat transfer is the way to go.
O.D. of 1/2" is .625" and 3/4" is .875"
1/2 in pipe is 23.5 sq in per ft
3/4 in pipe is 33.9 sq in per ft
HD has "M" 1/2" x 10' for $9.24 and 3/4" x 10' for $15.56

[GramaCindy]

Very interesting TrentonMaple. I have a Mason 2x4 and would like to upgrade to one of Jim's pans. Did you have him build you a raised flue or drop flue? Or just flat continuous flow pan?

[GramaCindy]

Oooh, I like the idea of going with a 2x5. Thanks for the info.

[KReinisch]

How farm did you guys hang the drip channels from the tubing?

[TrentonMaple]

I just used a hose clamp to bind it to the tubing where the Tee fitting slipped over the pipe. There is enough of a step-off to make a gap between the pipe and the channel for condensate to run.

Just as an FYI to anyone else making a similar preheater, I got mine all hooked up last night and ran the first bit of sap through it....EVERY soldered joint leaked. Swamped my sugarhouse and made a huge mess which then froze on the floor. See my other thread about it.

[KReinisch]

Do you have any close up pics of that?

[tendermason]

If you drain preheater so it does not freeze how are you cooling down the pan with no sap coming in to it to maintain proper level ?

[MISugarDaddy]

It takes some experimenting, but figure how much sap you need in your feed tank to allow your pan to cool down, and when you reach that level, stop firing your evaporator. I based it on how much sap I evaporated off per hour, and then used 75% of that amount. For example, my unit evaporated between 22 and 23 gallons per hour; I put a mark on my feed tank at 15 gallons; when I reached that point, I stopped firing. I would then let it start cooling down from that point. I always kept 5 gallons of cold sap in a pail to use to flood the pan after the fire went out to keep the sap level from dropping too low. At that point I would drain the preheater and pour that sap into the pan as well. I never once burned my pans using this method and you will be surprised at how much of that 5 gallons will evaporate off as your unit continues to cool.
Gary

[billyinvt]

Glen Goodrich says "don't flood the pan during shutdown." If you do, it'll be much harder to get your gradient started again when you fire up again. Let it cool down and draw off a pail of "nearup" to reintroduce to the syrup pan at the beginning of your next boil.