Home Made Steam hood & Pre-heater designs

[ibby458]

Once I get my new evaporator home, I want to start building a hood and preheater for the back pan.

Any particular pitfalls to avoid, or features that really MUST be included for it to work well?

20 - 24 gauge stainless is what I had in mind for materials. Is that too heavy? Light?

A friend has a sheet metal shop with plasma cutter, shears, brakes, rolls etc, so working it isn't a problem

[Fred Henderson]

Holy cow that is pretty heavy stuff. 28 or 30 ga is plenty, by the time you get it all bent it will be very stiff.

[Sugarmaker]

ibby458,
Sounds like you have all the tools. Man that would be nice!!!
Consider the weight if you have to remove yourself? These are awkward items.
Add internal drip edge with external drain.
Add damper to the rear hood to control steam if you are going to use/build a preheater.
Allow for doors or sliders in the hood/s to have access.
On the front hood I only made it cover part of the pan so I could see all the channels. ( See pictures on web page)
Support hangers for the front hood if it is suspended.
Room in the rear hood to get a preheater in, and consider how the pipes will feed into and out of the hood from the preheater.
Consider the size pipe for venting the steam. I have 10 inch on the front and rear both and they work well.

Hope this helps!
Chris

[WESTVIRGINIAMAPLER]

Irv,

Might want to check out my pics. Mine is about 30 gauge stainless and the frame is welded aluminum. The drip channel is 1" welded aluminum "U" channel that is square and it works great. My entire hood probably only weighs around 40 lbs for a 2x8. Also, my drip pan is bent down on each end and sits right down into the drip channel and empties into it. It is made out of about 14 gauge stainless so it has plenty of strenght and won't sag over time and adds extra strength to the hood. :D

[ibby458]

Thanks for all the great advice. I've looked at your pics and will borrow ideas freely. I guess 20 ga was too heavy, but I know where I can get some 26 ga. reasonable, too. Thanks!

[ibby458]

The Stainless 26 ga. ia all ordered and on it's way. Digging thru my piles of materials, I found 4 pieces of 3/4" finned tubing, 5' long. Will that be enough, or should I try to pick up some more?

Like everything else made out of metal, plastic or carried on a truck, the price of that stuff has gone out of sight. I'll buy more if I have to, but I'd like to make do if it won't hurt efficiency too much

[WESTVIRGINIAMAPLER]

1 or 2 more would be better! :?

[Fred Henderson]

Ibby, I got to go along with Brandon, in this case more is better. PM me as to what you paid for the SS to your door. That way when I go to buy local I will know how bad I am getting beat up.

[ibby458]

Fred - that 4x10 sheet of bright polished SS 26 ga cost me $144 delivered, and I bought another 4x5 sheet from the same guy for $77. That should be enough for the hood and drip pan.

A buddy of mine has a couple more lengths of the finned tubing for me. THat'll make 6, which should be good. Now I need to find a couple short pieces of 1-1/2 copper for the manifolds. With the prices being paid for scrap, any short pieces laying around have been sent to the scrapyard!

What should I use for the connection between the pre-heater and the float box? It would need to be easily unhooked to raise the hood.

[Fred Henderson]

Ibby, copper tubing is best. Put a union in and make it hand tight. Your hood should have doors in it so that you can get in there easily. To adjust the float and what not. Any that I have ever seen with an internal float have a door right where the float is.

[ibby458]

This one has an external float box. I was thinking a heater hose of some sort, but a brass union would work too.

I was planning a 4' flip up door on each side, with a lexan window (Although I haven't checked to see if lexan will take the heat). I'll mount my halogen lights on the ceiling, aimed in thru the doors when they're open.

I just came across a stack of used 8" SS stove pipe. I can get it free or pretty cheap. Will that be big enough to vent a 2.5 x 5.5 flue pan?

[maple flats]

I just looked at an online catalog for a company called maplebushsupplies from Michigan I think and a steam hood in 30"x 5.5 has an 8" stack collar so this should be good. If you are adding a preheater you also want a damper in it to be able to get it just right for the pre heater to perform best.

[Fred Henderson]

If one 8" is not big enough you can always use two. With a damper you should ckoke it down until you see steam just start to come out around the edges of the hood. This will insure that you are keeping enough steam inside the hood.

[mcmp]

I have used .250" lexan for years in the tops of my hoods. I have halogen spots mounted above shining through the lexan windows. It really lights up the inside nice. Never a problem with warping of the .250" lexan

Paul

[ibby458]

Glad to hear the Lexan will work for windows. I have a couple pieces of 1/4" that I was going to use, but I've also discovered that it's not terribly expensive brand new. Could I eliminate the SS door with lexan window, and go with a solid Lexan door 8x48"? I have a couple 48" SS piano hinges, but I'm not sure if the Lexan can take the stress without cracking.

A damper sounds like a must. I can build one out of some of the sheet metal scraps and a rod, with a wing nut to hold position.

When FK sent me pictures of this evaporator in action, a couple showed columns of boiling sap jumping 12" into the air. I wonder if these geysers will hit the hood, run into the condensate channel and be wasted? I had planned on the hood being 12" high in the center with sloping sides. Should I build it higher to avoid this?

[Fred Henderson]

I would say yes make the hood higher. Beleive me if that is lexan that you have and not plex-i-glass it will not crack. Lexan is some pretty tough stuff It can be drilled, bent like sheet metal and small pieces can be wrapped into a tight circle. That is Lexan that I made the windsheild out of for my RTV.

[mcmp]

Here is my concept on building hoods. I have built the same type hood on my last two evaps and will do the same later this summer for my new evap on order. In my opinion, hoods are a 'MESS' to remove for cleaning and maintenance, or Flue pan removal. They are ackward and heavy for one person. With this in mind, I build my hoods out of aluminum and then hang them from the rafters. Once in place they dont ever get removed. I fabricate removable skirts (sides) that seal between the hood and the Flue Pan. The skirts have a formed U Channel on the bottom edge that sits on the Flue Pan. I Brake the top edge 90 degrees to sit on the 90 degree broken edge of the hood. Three holes are drilled thru these two the top edges of the skirt and the edge of the hood. Then .250" almuinum pins drop in to secure the skirts. Four skirts totally enclose the flue pan. I have .250" lexan panels in the top of the hoods and 1 lexan panel on the long skirts each side of the flue pan. You can see in the picture the halogen spots shineing thru the lexan panels. Note how bright it is in the Syrup pan, the same is true in the flue pan. The Lexan panels just sit in a frame in top of the hoods, simply lift them out to clean. The Lexan panels in the skirt sides are pop rivited in place as they sit verticle.

The Pre heater is mounted in the hood. To remove the Flue Pan, or simply to clean the flue pan, just pull the (3) .250" pins on the top of each of the 4 skirts and your wide open as seen in the picture. You have enough room to stick your head in ( not when boiling ha ha). You get just a tad of steam from each of the skirt verticle joints where they touch each other. Not even enough steam loss to think about. My preheater out is 200 degrees, of course controlled by a damper in the flue pan hood steam stack. Condensate channels are fab'ed into the hood and a condensate pan under the pre heater.

I monitor my entire evap with Type K Thermocouples, steam hood temp at the pre heater level, actual sap pre heater output temp, smoke stack temp and more. I use Marcland draw off, backed up with a Omega CN1000-TC Programmable Digital Thermocouple with output. Both are running when boiling, in the event of a failure, simply unplug the drawoff valve from one controller and plug it in the other one. There are no Analog Thermometers on my Evap, just digital. The skirts were off when I took the picture. I have sold my evap and my sugar house is presently wall to wall empty. Later this summer I will post pictures of the new hoods with skirts once I get them fab'ed.

Paul

[/img]http://photos.imageevent.com/moosecreekmaple/sugarhouse/websize/9.JPG

[mcmp]

Well posting pictures failed LOL. How do I post a picture from my Image Event Site ? I clicked the img button and then inserted the address ???

Paul ( golly I hate computers LOL

[Banjo]

Since I wanted to look at the picture, here it is:
http://photos.imageevent.com/moosecreekmaple/sugarhouse/websize/9.JPG
Looks neat!

I'll put how to post in next posting.

cheers, Andrew

[Banjo]

It "should" be as simple as putting the following into your post:

http://photos.imageevent.com/moosecreekmaple/sugarhouse/websize/9.JPG

Where the url in the middle is the direct link to the picture you want.

If you want to get fancier, you can do a clickable thumbnail if your image hosting site generates thumbnails (or you do it automatically). Smaller pictures are a real bonus for the likes of us on dial-up. I like to keep things under 50kbytes regardless.

link to photo (http://link_to_thumbnail.jpg)

I was going to put in a real example, but it's so long it'll screw up the line length for the rest of this topic, so I deleted it! PM me if you want it.

(NOTE, I have clicked the "Disable BBCode in this post" box so that you can see the links. With this unchecked, which is the default, you would see the picture).

HTH, Andrew

Here's a reply I sent to someone the other week about pictures using PhotoBucket:

first you need to have your image uploaded to a site that you can link to. I use PhotoBucket.com which is free and has some other good features too.

Then you need to put in the "image" BBCode. There are buttons above the message editing window that help a bit, the Img one is second from the right.

The code will look something like:
http://image_url where you edit the image_url to be the link to your picture. Easiest way is to have it up in another browser window and cut and paste it.

With PhotoBucket it's even "easier", in that it will automatically generate the code you need. Once you have your picture uploaded into PB, you can select it and click on "Generate" and it'll create a bunch of them that you can pick from and then just cut and paste it into the message. I use the clickable thumbnail ones which are easier on dial-up users as they don't have to wait for a big picture to download.

I can find an example of this, and get the exact buttons if it's still too murky!

[mcmp]

Banjo;
Thanks. I see my problem, I did not close the url with the "img'
I like the simple way and small pictures, I too am on a s l o w dial up.

Paul

[Banjo]

Paul, "all part of the service" as they say. You're an expert now! Thanks for sharing the pics.

cheers, Andrew

[ibby458]

Great ideas, and great pictures! I was planning on putting an attachment point on each corner, with 1/8" cable hooked to it. Each cable would go thru a pulley overhead, and end up in a winch on the wall for raising and lowering.

I was hoping to get the whole flue pan hood out of one sheet of 4x10 SS, with the 4x5 sheet for drip edges, drip pans, etc. I Haven't quite got that figured out yet, but I'm still working on it.

I've heard that you get a lot less scum and foaming with a steam hood. Is that true? It would be a handy plus!

I like to keep track of things too, and plan to stick thermometers everywhere. Since I already have a box full of dial ones, that's what I'll use. Stack temperature, incoming sap (to preheater) and outgoing sap, and inside hood temperature for sure.

[WESTVIRGINIAMAPLER]

Ibby,

I never skim my syrup or flue pan. Definitely still need defoamer in the flue pan. :)

[brookledge]

I agree with Brandon, never need to skim but certainly need defoamer
Keith

[ibby458]

Off to home Depot today for some 2" copper pipe, fittings, etc. Better bring the heart pills!

[WESTVIRGINIAMAPLER]

2"??? 8O Guess you had better take some pills. 8O My preheater is 3/4" and the manifolds are the same. Just 3/4" "T"'s as close as possible. 3/4" would be plenty for that size evaporator. :?

[ibby458]

I think 3/4 is gonna hafta do it. My idea was to create a larger capacity on each end, but at $40 for 10' of 1-1/2" (when I only need 3') I think a redesign is in order. I think I can get a couple short pieces of larger stuff elsewhere (I have a buddy that works in a scrap yard), but even then the fitting cost is outrageous!

[MASSEY JACK]

Scrap yards are great..........but....how do you know what that pipe was used for?? I have seen 2 inch copper gray water drains in houses!!! I am going to build one for my 2.5 x 8 and am going to use 1" on the ends and 3/4" runs.

[maplehound]

Another good Question nOw is. Why has Canada outlowed the use of copper preheaters? I just ordered a new hood for my 3x8 ( 3x5 flue) And they are putting in a used preheater for me. Total cost is $1300. The hood by itself was $1100. They are selling the preheater cheap since there are so many on the market with the new change. I just don't understand why they have outlawed the copper? Unless it is to get rid of the solder!!
Ron

[brookledge]

ibby458
If you still want to use a large dia. on the ends go to a plumber and ask if they have any short pieces might get it for next to nothing or barter with alittle syrup
Keith

[Fred Henderson]

The headers don't have to be any larger than the float intake pipe. If ya got 1" going in then have 1" coming out to the float.

[WESTVIRGINIAMAPLER]

Don't know why they would have outlawed copper as I soldered mine, but made sure it was lead free. According to some on here, you have to remember that those people north of the border are a ton smarter than us when it comes to maple. 8O The problem with stainless it that it won't heat with steam nearly as well as copper and I used the thin wall copper pipe so it would heat even better. :?

[ibby458]

It's starting to look like 3/4 is the way to go. I have a coil of 3/4 soft copper laying around, and that's what I'll use for the pipe from tank to preheater, and preheater to float box.

My son is a plumber, and cutoffs get scarfed up by the homeowner or apprentices before they hit the ground, for the same reason that I don't still have that pile of 2". Scrap copper price is too high for anything to be left hanging around. (Wish I would have saved SOME of it, but I had had it for years and never used any) I had 2-150 gallon copper tanks, too. Once I went over 200 taps, they wouldn't hold enough so I scrapped them, too. Got almost $500 for the two tanks and pile of 2" pipe. Wish I had held it all. Price is double what it was when I sold it.

[ibby458]

THe 26 ga. stainless came yesterday. I am SOOOO glad I was warned not to get the 20 ga. I had originally considered! The 26 ga. is PLENTY heavy to pick up the rolled sheet. Wish I had gone 30 now.

It's not the mirror polish I expected (and was advertised to be) but it'll still work. I briefly considered asking my wife to get after it with polishing compound, but decided my life was worth more than a shine on the steam hood.

[ibby458]

My buddy's wife threw out the finned tubing he was going to give me. In exchange, he offered me a new 30x30 heating coil. It's small diameter tubing in a aluminum finned grid. If I put that in my hood so the steam has to go thru it slowly, it'll heat like crazy. My only concern is the inability to clean it, other than just flushing it good. Will that be good enough?

[Fred Henderson]

That is the way that any other preheater is cleaned.

[maplehound]

Ibby
How small is the tubing running through it? Does it have enough of a flow rate to flood the pan in an emergancy?
Ron

[ibby458]

Excellent point. I hadn't thought of that!

There's a 1 inch inlet and outlet manifold, with about 24- 1/4" tubes connecting them. I think it might flow fast if I opened the valve wide open, but maybe I should put in a bypass to dump directly into the pan.

I'll have to set up a test. I can put a tank up on the platform about the right height, and see how much flow I get thru it.

[maplehound]

Ibby,
Sounds like a good idea to test it. You might also look into getting a used preheater out of Canada. I just ordered one and the dealer told me that Canada now has alot of good used ones available real cheap. I got one fitted into my new hood for only $300 for my 3X8. I didn't think I could build one for that.
Ron

[Fred Henderson]

Is the tubing in that used preheater solder? If yes with what type of solder.

[ibby458]

Actually, this heating coil I have is soldered, and it could very well be lead solder. Still - it has little exposed solder, and my evaporator has a whole lot of exposed lead solder, so I doubt the preheater would hurt much.

I do have to do some repairs (that's why they were throwing it out), and resoldering the whole thing with lead free solder isn't impossible.

If this won't flow enough, I might look into the canadien ones. Where should I start looking?

[maplehound]

I am sure that they are soldered. I am also relativly certain that it is lead free solder, although I haven't been told so.
I am buying mine through a Dellair dealer but I am sure that all the canadian companies have the same problem. I would start looking, by calling your dealers and asking them.
Ron

[ibby458]

Started drawing up plans for the hood, to fit the 24x24 coil as a preheater. The parts fit on the sheets of 26 gauge much better, but it'll sure look strange. Kinda like a pyramid from the sides. Still - It'll funnel all the steam thru the coil fins, and that's what'll make it efficient.

My drip channel along the sides are 1" wide by 2" tall. Does that seem right? It seems tall on the inside, but any less than that might hook onto the flue pan rim when it's sitting on the pan.

The drip pan under the coil will be 1" bigger on each side, and 1" away from the sides of the hood (96 square inches of steam space) After if passes thru the coil, it gets necked down to a 8" round pipe (50 square inches)

Will 3/4" copper be big enough to drain the pan into the drip channell? I'd planned to flare the end of the pipe (soft copper) and solder it to the bottom of the drip pan, drilling a 3/4" hole after it's soldered on.

[Hal]

A couple of things you might want to think about.

If you are going to use the hot water from the hood, and I am sure you will, you might be happier to separate the runoff from the drip pan from that of the channels on the sides. The side channels will pick up a certain amount of foam and spatter from the boiling sap, unless you have a really deep pan and are very faithful about using defoamer. The drip pan, being higher up and more shielded will be much cleaner.

The other thing is that you should use a threaded fitting designed to be soldered to a pan for your drain, something like they use to attach the drawoff valve to a front pan on a soldered pan. It will give a flat surface to solder to, and much more area for the solder to stick to. Another advantage is being able to remove the pipe, and not have it hanging out in the way if you have to move the hood/preheater assembly for any reason.

[ibby458]

This is a fairly deep pan, but I see your point and think it would be easy and worthwhile to implement your suggestion. How much water should I expect out of a 2.5x5.5 flue pan? I had planned to keep a bucket under the drain, and let the overflow wash the floor.

I have a catalog that lists the fittings you're talking about. If I need to order anything out of it, I will order one, but if I don't,, I think I'll stick with the flared copper idea. Making the down pipe removable makes sense and wouldn't be hard to do. Will be a lot less bother to take it apart for cleaning, adjustments, etc.