4x12 Airtight door and pre heated AOF mods.

[madmapler]

Here are some pics of my airtight door and AOF with preheater. This is an old grimm oil fired arch I picked up over the summer. It needs some cosmetic work but all in all its in pretty good shape. I welcome any comments on the design especially the AOF preheater. I'll be editing and adding to this post because I can't post too much without losing my work for some reason. Here are the door pics.12023 12024 12025 12027 Some of the welds are messy due to some flux core wire I used and lack of experience. Apparently I can't add more than 5 pics to a post so I'll post a second time with the AOF pics.

[madmapler]

Here are my AOF pics.12029 12030 1203112032 12033 The air comes in the back of the evaporator where the oil blower is pictured. I have a Dayton High pressure blower I'll be mounting in the next room and piping to that inlet instead of that blower. From there it goes into a manifold I made out of 4x4 square tubing with the six outlets that are pictured. It then runs under the flue pan through 6- 2" pipes that turn downward at the other end and go into an airtight sheetmetal plenum behind the ramp. That in turn feeds the 1/2 tubes in the ramp as well as the 2x4"rectangular tubing that runs down either side of the firebox. I read on Proctors AOF guidelines that preheating the over fire air can improve the efficiency by up to 15% I believe. I think this will work good because I started the blower after welding on the rear manifold and was surprised at how warm the air was that came out and for how long it lasted. I'm kinda sticking my neck out with this design so If anybody sees any potential failures feel free to comment. I'd rather deal with issues now than during the season.

[maple flats]

The only issue I see might be that you will need a faster filter and a faster way to move fully loaded barrels.
Looks like a great job, love your design.
A high pressure blower is loud, you may want to place it in a vented, soundproof cover outside.
Mine sets outside, on a shelf under my head tank and is connected by 4" PVC pipe, has a fernco connector between the blower and the pvc, plus it has foam insulation surrounding the PVC where it penetrates the sugarhouse, it is still quite loud.

[n8hutch]

Nice work, this gives me some ideas for preheating my air over fire, I am converting my arch this winter, my New Air Tight front came in yesterday. But I will have a lot of Iron pipe plumbing to do as you have. Thanks for posting.

[Flat Lander Sugaring]

just want to make sure you dont choke down the stack area with preheater tubes, you definitely want to leave the same amount of cubic inches going through the area from the arch to the stack after your tubes are in. or maybe i am over engineering it, thats what I did with mine when I built it.

[madmapler]

just want to make sure you dont choke down the stack area with preheater tubes, you definitely want to leave the same amount of cubic inches going through the area from the arch to the stack after your tubes are in. or maybe i am over engineering it, thats what I did with mine when I built it.
I see what you're saying and I thought about that too. There is a little space over the manifold and I plan to stack some old firebrick and blanket to within about 6" of the front of the manifold then leave space for the flame to go underneath it. I hope that will work but I welcome comments. Is this similar to what you did? Yours is the only other preheater I'm aware of.
Dave, The sugarhouse is attached to my garage. I'm going to put the blower there and pipe it in. Thanks.

[Robert K]

A well built motor is good, a well built motor with a blower ---- insert evil laughter here!!!!
Nice job, I gotta get working on my preheater now that I have seen this.
Thanks
Robert. :evil:

[madmapler]

Just updating this thread with the results of the preheated AOF mods.(pics below) We did a test boil today not having any idea how things were going to turn out and surprisingly, it went real well. We started a small fire and worked our way up. We then tried the auf which is a 5" blower off a jennair exhaust fan. With the hood off and no preheater, we had a violent boil in the front of the flue pan, considerably tapering off to a mild boil in the rear. Once the whole thing got up to temp, we flipped the switch to the 3hp. Dayton high pressure blower and it was like hitting the nitrous button. We had a strong boil everywhere we could see and the steam over came the cupola so we had to open the doors. We were able to cut back on the auf about 50% without changing the boil rate much if at all. The wood lasted quite a bit longer than without the aof but we didn't have enough water to really get the full experience. I can say at this point though that it seems to be working really well and so far I'm glad I took the chance. I'll post again once I've been boiling awhile.

[n8hutch]

Sounds like your on the right track. I didn't get to redoing my arch this year. Just not enough time. Going to track your success and hopefully get to mine next season. Feels kinda stupid having A brand new air tight front leaning against the wall.

[Waynehere]

Hey Sean, how did the mods work for you then? Hope you had a good season... :)