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[paperman]

Modeled a bit after the commercial units I see, a dash of some home builds on this site and then a touch of stuff I am dreaming up as I go after I started my build.  Hope to be on-line next year this time.  This is what I built up tonight.  I have the outer tank welded out with the exception of one side.  It is 5x6x3  1/8".  The fire box is salvaged 1/4" 48" deep 30" wide, seconday is 12x12". 

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[paperman]

OK been welding my tail off.  Fire box is just needing a pass on the inside of the ends, Ill post pics soon as I take them.  I ned a bit of help on the nozzle going into the secondary.  Round, square, how big is too big?  I was thinking 2X6 as a starter? The other thought was a set of  truncated cones about 1.5".   The actaul bottom of the primary is planned to be cast refractory as I have pallets of the stuff.  It will be backed with steel but it will allow me to play with the nozzle a bit if needed.  I if its to big or small I can recast that part and try again. 

Leak checked the water tank and found 2 pinholes.  Leaked a drop every 5-6 second.  8 seams are good only 4 more on the tank.  Thinking on how to pressurize the whole furnace and leak check with soap before its installed in the tank.

[paperman]

Ok not much in the way of photos but here are a few to keep you all tied over for a bit.  Lot of time getting it all planned, cut, and fit so the actual time under the hood has been a bit lacking.  First pic is the backside of the tank welds, I was getting them burned in nice.  2nd is of the outer tank finished, 3rd is the door opening in the firebox end as its being fit.  More to follow.......

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[paperman]

Anybody make a door gasket with hitemp RTV?  I was thinking of using a tube of RTV in the door channel and put a release agent on the opening rim.  Set the door on and let it cure.  That would make a perfect seal if it worked.  I was planning to use some Teflon gasket material we use at the mill but then thought of the RTV.

[Bondo]

Anybody make a door gasket with hitemp RTV?  I was thinking of using a tube of RTV in the door channel and put a release agent on the opening rim.  Set the door on and let it cure.  That would make a perfect seal if it worked.  I was planning to use some Teflon gasket material we use at the mill but then thought of the RTV.

Ayuh,...   I did just that, Sorta,....

I used a rope gasket from Rutland originally, but their cement failed, miserably...

Rather than strippin' all of it out, I just used Hi-temp RTV, 'n reglued the gasket into place...
For a release agent, I just lined the lip with suran-wrap, til the RTV cured...

The plastic wrap disappeared the 1st time it was refired, 'n the rope gasket/ RTV is still goin' strong after 2 seasons...

[paperman]

Just a picture of the plan I drew up adn am working off of.  Keep in mind I am no engineer, but the drawing helps you to see how things really fit.  A pen line on a bar napkin might look great but those lines have a tendancy to "self scale", they always fit just right.  Sadly in real life the steel doesnt move as easy as the pen. 

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[paperman]

Finally back to work on the burner.  First shot is of the back end, first pass.  The flues are 2.5" and there are 10 of them 33" long.  They run up to a shared chamber with the bypass and the intake of the 2nd pass.  This transition area is tapered to give more room for the door on the lower chamber.  All the flue locations are marked from printouts I made from my drawings.  That way they are all in the same location on every sheet.  Laying out with a square is OK but its easy to get out of dimension pretty easy.  Its even easier when its cold and your digits dont work as well as you would like.  With the prints its easy. 

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[paperman]

I was crawling around the inside of the fire box.  Not allot of fun in there.  Welded the inside of all the seams.  Started the layout of the 12 2" tubes headed to the front of the furnace.  This is the 2nd of 3 passes I had planned.  Ill post pics of the circle cutter I made to attach to my torch.  Was planning on using the plasma till I found my circle cutter for that would not go small enough.  I have the passes going slightly up hill.  Dont know if it helps or hurts but thats they way it is now.  First pass tubes are welded out and waiting for me tonight to finish the bypass so I can start getting that transition box done.  Still haven’t figured on how I want to get air into the firebox.  I thinking high entry with the charge pipe running down steeply to the fan plenem box.  Figured the heated air all the nasty stuff wouldn’t want to travel down the pipe to form the build-up?   

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[paperman]

Slope is about 1.5" in 40".  The 6" tube is only there for support and fit, not part of the install.  I could ahve gotten more done but we had to press one more round of apple this year.  Found an orchard that was full of appples.  That in itself is VERY rare this year in MI.  Even better was they were all given to us.  Pressed 110 gallons on this old gal.  Rebuilt it from a rusty pile of part this past summer.  Ill try and get moving on this thing, just paid the gas man to fill the propane tank.  Thats another $1000 Ill never see again.

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[Roger2561]

That cider press brings back memories from when us kids used to help our dad press apples for cider.  There is nothing in the world that tastes better than freshly pressed cider.  Thanks for taking me down memory lane.  Roger

[paperman]

Layed in a few of the 3rd pass flues.  Seem I will end up with about 6" of water over them in the end.  My angle ate up about 3" of what I had planned.  Anybody think that will be an issue?  The top pass is the coolest of the bunch.  Also after some input I think I need to rethink my nozzle dimensions a bit.  Seems I am thinking way to big.  Same with the area of the flues.  Never thought about condensing the moisture out in the gas path but after thinking about it I would think that could be an issue if you pull to much heat out.  I may need to plug a few flues if it becomes an issue. 

[dwneast77]

This looks fantastic!!!  You're doing a great job IMO.  Heat exchangers set up much like Portage and Main.  You're secondary combustion chamber looks a lot like my Wood Doctor.  That uses all 8" square tubes, for the combustion chamber and for heat exchange to the water..   If this helps,  my WD's nozzle is set up completely with refractory brick.  They've lined it up crossways over the combustion chamber with 4 slots open to the combustion chamber of approximately 1" wide and 6" accross.  Personally, I think the nozzle openings might be a little on the big side as I get a rather large amount of coals falling down through.  Also the fire is not as intense as it could be (not the same torch effect that I get from my central Boiler) and I get a lot of ash to clean out every few days.  Also the nozzle openings are favoring the front end of the firebox putting the hottest fire at the front causing the wood the burn more quickly at the front so I end up raking coals to the front at the end of the burn cycle.

For air supply, the Wood Doctor uses an easy option.  First off it's a negative draft, a fan installed in the chimney sucking the air/fire through.  I know that some of the bigger models on the market actually use both positive and negative draft together.   Anyway, the Wood Doctor design just sucks the air in through a tube mounted so that the air is introduced at the wood fill door.  That tube has a high heat flap with a motor attached to open/close.  I'll get a picture tomorrow.  Maybe it interests you.  The only point I'd like to stress is this,  Keep your primary air supply simple and/or removable for cleaning!!!  I've had major issues with my Central Boiler primary air channel and finally had a welder come in and we put together my own design.  Works better than ever, and I can clean it if necessary, which has not actually even been necessary.  I'll post that pic now.  Even Central Boiler has re-designed to allow removal for cleaning.


Keep up the good work.  I look forward to seeing your progress.  I wish I had a shop and knew how to weld.


Jeff

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[paperman]

Thank you a bunch for the information.  Id love to see more pics of how the real machines are built.  I was planning on putting the outlet nozzle on the door end of the firebox.  My thought was if we are truley burning the wood gas any pyrolizing the wood them placement should not matter much.  With the outlet on the door end it makes the secondary a one way street.  I guess we will see how it works next year.  If its a bust then I can bust out the floor and move it.  Thanks again and Id love to see more photos.

[dwneast77]

Here are a couple of shots I took of my Wood Doctor to give a little idea of the layout of the air inlet.  The 4" pipe attaches at the right side of the feed door and 90 degrees down to about 1' from the floor.  That's where the motorized flap is located to stop air flow (currently open in the picture).  There is a vent in the upper left corner to allow for the draft.  This preheats the air as it is coming in at the top and drafting down past the stove doors to the floor area.  Those inner doors are not insulated so it does get quite hot in there.  The outer shell door of course is insulated.  I will be shutting this boiler down tomorrow and firing up my CB.  So I will be able to get a pic or two of the inside of the firebox to show how the bricks are layed out.  The nozzle slots between the bricks are crossways and do favor the front of the firebox which does cause the wood to burn faster in the front and then the logs fall forward.  I wish it was centered better myself.   

The nozzle in my CB is half-moon shaped running front to back with the arch on the right and the flame goes down and to the right into the secondary burn chamber.  This nozzle is centered in the firebox and usually the wood burns much more evenly. 

If you check out P&M's web site you'll see that they just have a straight slot running front to back.

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[paperman]

Holy bunch of doors Batman!  Can you give me a run down of what each one opens into?  Is this the front or back of the burner?  Seems like it feeds lots of air into the primary and just a touch to the secondary.  Or is this not a true gasser, maybe feeding a little bit of air under the grates and then a bunch over the fire to help burn clean.