Preheater hood advise

[The Sappy Steamer]

I want to build a preheater hood for my 2x6 raised flue. Does anyone have any helpful hints they could pass along?I downloaded the pictures wv mapler had, but I'm not real clear on the water channel and all that. I could not really make that part out well from the pictures I saw. I've never seen one up close, and don't know anyone that has one. I keep thinking that I must be overlooking some intricate design particulars when the price quotes I am getting are all around th th th three thousand dollars. That's not gonna happen until I've spent more than that trying to avoid paying that.(Huh?) I also would like to know if two steam stacks are worth the addition trouble going the the roof of the shack. Doesn't appear so to me, but I imagine it would get the steam out quicker. I would appreciate ANY input from anyone.

[WESTVIRGINIAMAPLER]

Sappy,

Shoot me a PM or give me a call and I will try to answer whatever questions you have and help you. My hood was built by an Amish in PA for $ 440. If you don't mind driving a little, he does great work. He built a really nice hood for Larry Harris who is a trader member last fall also and it was about the same price! :D

Cell 304-575-7266

[Sugarmaker]

Steamer,
Lots of hood designs and options for materials, and prices.
I gleaned stainless off of Dari-Kool bulk tanks ($100 to $250 for the tanks) and then fab-ed the hoods myself on the work bench in the garage.
Total cost of the hoods and stacks about $300 (without my labor).

Hoods are nice to remove the steam bath effect of open pans. But surely not a requirement to make quality syrup.

Seems you should be able to get them made for $500-$600?????
How much are they from Leader Catalog??

Drip edge is typically a upturned channel on the inside bottom edge of the hood with a external drain, to let the condensate run off.

I chose to go with two stem pipes as the back hood has a damper to control steam flow for the preheater.

Some pictures on our web site might help?
(when you go to the picture page click on each of the photos to bring up the pictures, and then to the right and left of the thumb nail photos at the top you can click to see more pictures in that series.)

Regards,
Chris

[The Sappy Steamer]

Hi Chris,
It's sounds like we think alike. The hood I made for my other evaporator was made from similar material,but it wasn't a preheater hood. I had built a small preheat pan to piggyback on my flue pan. It's better than nothing, but not real high tech.The only trouble with it is when I really get crankin, the sap has to be fed too fast to get really hot. I came across another bulk tank this summer and made a good buck on the copper inside, what with copper prices being so high. I made decent money to take it off the peoples hands. I wish I could find more of those deals!
Some questions I have are if the channel on the outside perimeter of the hood and the condensate pan have separate plumbing to get the water out and do you valve it ,or just let it trickel out all the time? Also, how do you regulate the preheater properly using the damper? What are you using to monitor the temp?
Well anyways, thanks alot for the post. I did check out your website, and was very impressed. It looks like you have a really top of the line operation there. Have a great day. Dan

[Sugarmaker]

Dan,
The condensate channel is on the inside of the hood on the perimeter, it has a fitting welded on the outside of the hood and a line runs to the drain. I really don't get much from this. The condensate system under my preheater is not a tray it is 1 x 1 aluminum angles that slope to the back and then feed into a cross tube which exits thru the side of my pan and runs to the drain. From this I get about 6-7 gallons of 200 degree hot water per hour.

I regulate the amount of steam under the hood which in turns controls the temp of the sap coming from the preheater. The damper is in the steam pipe. This is a must with a preheater, Unless your steam pipe would be sized perfectly to act as a damper.
When I have the damper closed to much the steam starts building up in the hood and is forced out every crack and crevice. When the damper is wide open all the steam escapes and the sap doesn't get hot in the preheater. I installed a thermometer in the preheater tube just as it drops in to the float box and when everything is running smooth the sap will be about 190 to 200 deg F coming out of the preheater. Which is about all you can expect.
Thanks for the comment on our sugar house. We got high marks from the 60+ sugar makers that came thru on the state tour.

Hope this helps,
Glad to try to answer any questions. But I do not by any means have all the answers! i enjoy the hobby, and maple folks, that's what it is all about!

Regards,
Chris

[The Sappy Steamer]

Chris,
Thanks for enlightening me on the preheater operation. This may sound like an ignorant question, but if you need to damper your steam pipe down too much to get your sap preheated enough, will it effect your evaporation rate? Or is it not worth the consideration?
I couldn't agree more as far as the hobby,and maple folks are concerned. I tell my bewildered friends and relatives" It's not about the syrup as much as it's about the lifestyle" They don't get it.
Thanks again,
Dan :)

[HanginAround]

I heard recently that current theory is not to dampen your steam from escaping... that the loss of effiency in your preheater is made up for by increased boiling rate due to lower pressure in your hood. Not sure how you could measure it, but it makes some sense. For the same reason that things boil easier on a low pressure day, a slight increase in pressure in your hood slows boiling. On the street, people are still damping it though.

I wonder if a person put the steam stack inlet below the level of your tubes you would keep them covered with steam without damping the flow... just thinking, never saw or heard of it done.

[Russell Lampron]

I close the damper on my hood when I first sart boiling to get he pan up to a boil faster. It is much like covering a pot when you boil water. As soon as I have a good boil in the flue pan I open the damper all of the way and leave it that way. The preheated sap is going into the flue pan at about 185 degrees when everything is stabilized.

Russ

[brookledge]

I don't think that slightly pressurizing the hood by dampening will slow your evaporation rate. By adding pressure it increases the temp of the steam. At 1psi steam is 215 F and at 5 psi it is 227 F. When you add pressure by dampening the steam still is coming out of the hood.
I look at it like the pressure cooker that some use for boiling food on the stove. The weight on top adds pressure so the the steam will be much hotter than 212. If you leave it the water will still boil out.

Maybe we can get some input from someone with a physics background to input.
With my hood and pre heater the first year I used it, I didn't have a damper my pipe is 10" and I couldn't find one locally The temp coming out was about 180-185. The next year I bought one on e-bay and now my sap is at 200-205 If I dampen it too much it will boil inside the preheater.
I saw an increase in evaporation rate.
Remember that 1 BTU is needed to raise 1 pound of water 1 degree so you also save on fuel by increasing the temp coming out of the preheater.
Keith

[The Sappy Steamer]

I think I'll opt for keeping things simple and experiment with dampening to find the best balance between preheater sap temp and evaporation rate on my particular setup. Which, I believe is what Chris has already done. I'm afraid that I may still need to experience the physics to learn them, rather than learn the theories. Much in the same way I learned the toaster was really hot when I was four years old. FOR WHAT EVER REASON! We all have differant ways of learning. Mine usually leave a mark. :)

[HanginAround]

Of course, and sorry for getting a little deep into that... I started a new thread to get that topic out of yours.

The basics are to bathe your preheater tubes in steam to re-capture that heat before it goes up the stack... in the process you will have condensed steam dripping off the tubes, running back down the stack, and off the hood itself that you do no want to fall back into your boiling sap... you already boiled it out of there once. A drip tray under the tubes catches it and has a drain to the outside, and a drip channel all around your hood and plumbed to the outside catches all that runs down the hood before is can fall back into your sap. The channel is basically the bottom edge of your hood bent inward and upward to form a squared "U" on the inside. Put a drum or other container under your drains, and you will have all the hot water for cleaning you can use. This is distilled and pure too, so is great for coffee, instant soup, or tea, hold your cup under your drain.

I saw some great ideas here for lexan windows and removable sides too, but have forgotten whose ideas these were.

[WESTVIRGINIAMAPLER]

I had lexan windows/doors, don't try those. :?

[HanginAround]

What happened to your lexan?? Is there another good substitute?

[WESTVIRGINIAMAPLER]

Too much steam warped it. Might would have been fine if it had been about 5 or 6 gauge thick. :?