Insulated Vertical Reverse Flow cabinet

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strength_and_pow
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Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Fri Feb 14, 2020 1:54 am

I have this in progress. Tried to design the whole project before starting but didn’t get anywhere with it so I had the body formed and I welded it up so I had something tangible that I could measure.
Body is 11ga CRS with 2” rockwool in the walls. Door are a double pan in a pan construction giving the doors a stair step with 2-1” layers of Rockwool and 7/16” overall thickness of steel. It will be a reverse flow and the smoke will flow up the false walls and down through the cook chamber exiting at the smokestack at the bottom. On my divider plate between the firebox and cook chamber, I have the option to use some of this for the plate and also as a shroud for a water pan. The two chambers will be sealed from each other with the only connection being between the two through the false walls.
I’m thinking the thicker plate will take longer to come to temp ( I will be using gas assist to warm up the cook chamber) but should also balance out any spikes in heat because of its thickness.
What is yalls opinion?

Here is a few pics. The punch list to get this thing smoking is dropping. I plan on a full write up once complete.
Thanks
Scott

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Txdragon
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Re: Insulated Vertical Reverse Flow cabinet

Postby Txdragon » Fri Feb 14, 2020 1:58 am

Beautiful project! I look forward to seeing the writeup!
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Re: Insulated Vertical Reverse Flow cabinet

Postby spacetrucker » Fri Feb 14, 2020 8:00 am

outstanding project!! :cheers:
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PinoyPitmaster
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Re: Insulated Vertical Reverse Flow cabinet

Postby PinoyPitmaster » Sat Feb 15, 2020 12:35 am

Do you think smoke will travel against gravity and flow down and just get trapped up there?


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Re: Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Sat Feb 15, 2020 7:20 am

PinoyPitmaster wrote:Do you think smoke will travel against gravity and flow down and just get trapped up there?


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Not sure I follow you.
Not shown is a horizontal plate that will separate the fire box from the cook chamber. The left, right and back walls with shelf brackets will be an inch away from the actual walls of the unit and stop 4” short of the top. Smoke will rise through this passage then drift down and exit out the smokestack at the bottom. I’ve seen this on several commercial units that have a good name and. The reviews all say it produces good food. I’m sure someone with a degree in thermal dynamics or something could give an explanation how it actually works but that person hasn’t shown up yet. My question is, how thick should the horizontal divider be? Thinner would heat up faster. I thicker piece would heat up slower but would change temps slower based on the mass alone of the plate. This plate will be steel only, no insulation.


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bsooner75
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Re: Insulated Vertical Reverse Flow cabinet

Postby bsooner75 » Sat Feb 15, 2020 9:17 am

Where are you located? I have an insulated reverse flow cabinet I’d be happy to let you check out if you’d like. I didn’t build it so can’t really help you there but If you are in DFW you are more than welcome to look at it.


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Re: Insulated Vertical Reverse Flow cabinet

Postby k.a.m. » Mon Feb 17, 2020 11:15 am

Very nice work Scott. :salut: :salut: :salut:
I would use 1/4" material to separate the two chambers. Pit Maker found out real quick that 1/8" will warp in their vaults and went to 1/4".
For those interested on how the reverse flow cabinets work it is cabinet pressure. The heat smoke enters the cooking chamber and creates pressure due to the gaskets and heavy insulation basically forcing the heat smoke down and out the only way it can. Normal preheat for vaults is with a weed burner and heat up the exhaust to speed up the draw.
I hope this helps. :D
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strength_and_pow
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Re: Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Mon Feb 17, 2020 12:35 pm

k.a.m. wrote:Very nice work Scott. :salut: :salut: :salut:
I would use 1/4" material to separate the two chambers. Pit Maker found out real quick that 1/8" will warp in their vaults and went to 1/4".
For those interested on how the reverse flow cabinets work it is cabinet pressure. The heat smoke enters the cooking chamber and creates pressure due to the gaskets and heavy insulation basically forcing the heat smoke down and out the only way it can. Normal preheat for vaults is with a weed burner and heat up the exhaust to speed up the draw.
I hope this helps. :D


Do you see any reason why 1/2” wouldn’t work? I have a chunk the was free from work. I had originally planned on 3/16” but I’d have to buy it. At this point in the build, buying $20-30 more of material is a drop in the bucket, I could have bought one and been smoking already and be dollars ahead. But I enjoy fabrication so there is that


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k.a.m.
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Re: Insulated Vertical Reverse Flow cabinet

Postby k.a.m. » Mon Feb 17, 2020 4:06 pm

strength_and_pow wrote:
k.a.m. wrote:Very nice work Scott. :salut: :salut: :salut:
I would use 1/4" material to separate the two chambers. Pit Maker found out real quick that 1/8" will warp in their vaults and went to 1/4".
For those interested on how the reverse flow cabinets work it is cabinet pressure. The heat smoke enters the cooking chamber and creates pressure due to the gaskets and heavy insulation basically forcing the heat smoke down and out the only way it can. Normal preheat for vaults is with a weed burner and heat up the exhaust to speed up the draw.
I hope this helps. :D


Do you see any reason why 1/2” wouldn’t work? I have a chunk the was free from work. I had originally planned on 3/16” but I’d have to buy it. At this point in the build, buying $20-30 more of material is a drop in the bucket, I could have bought one and been smoking already and be dollars ahead. But I enjoy fabrication so there is that
While it is overkill it will work with no problems that I see.


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Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Tue Feb 18, 2020 10:13 pm

k.a.m. wrote:
strength_and_pow wrote:
k.a.m. wrote:Very nice work Scott. :salut: :salut: :salut:
I would use 1/4" material to separate the two chambers. Pit Maker found out real quick that 1/8" will warp in their vaults and went to 1/4".
For those interested on how the reverse flow cabinets work it is cabinet pressure. The heat smoke enters the cooking chamber and creates pressure due to the gaskets and heavy insulation basically forcing the heat smoke down and out the only way it can. Normal preheat for vaults is with a weed burner and heat up the exhaust to speed up the draw.
I hope this helps. :D


Do you see any reason why 1/2” wouldn’t work? I have a chunk the was free from work. I had originally planned on 3/16” but I’d have to buy it. At this point in the build, buying $20-30 more of material is a drop in the bucket, I could have bought one and been smoking already and be dollars ahead. But I enjoy fabrication so there is that
While it is overkill it will work with no problems that I see.


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Half inch it was. Broke out the 350p for the task.
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Re: Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Sat Mar 07, 2020 1:28 pm

So I forced myself not to post the build write up until the unit was actually complete. My work schedule can get hectic and projects can drag on for far too long. Happy to say this was not the case. I officially started the build on Christmas Day 2019 as I was off work and my family had already celebrated Christmas 2 weeks prior as that’s what worked with everyone’s schedule. 73 days later, I have coals in the firebox and am doing a burnout prior to seasoning.
My local fan shop, Western Sheet Metal formed the inner and outer bodies from 11ga CRS in November 2018. Things sat for a good bit, work and life dictated this delay.i used 2” Rockwool insulation on the body although the back only has 1” due to a measurement mistake. Chimney was built into the back wall. There isn’t a ton of information on this type of smoker. I used the Feldon’s calculator for a reverse flow as a base and looking at various manufacturers of similar offerings, I came up with my dimensions on firebox and cook chamber size. ImageImageImageImageImageImageImageImageImage


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Re: Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Sat Mar 07, 2020 1:32 pm

While I was working on this, I fired up the pellet pooper I keep at work and did up a small prime rib roast. The pellet pooper was bought on a whim, seemed like a decent piece but only got 3 cooks out of it before it shat the bed and I’ve had to get warranty parts.ImageImageImage


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Re: Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Sat Mar 07, 2020 2:00 pm

Using the aforementioned calculations I then installed the front divider which gave me the information I needed to determine my door dimensions. I was also able to install the back false wall which is one of the three sides where the smoke will pass through
ImageImageImageImage


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Re: Insulated Vertical Reverse Flow cabinet

Postby strength_and_pow » Sat Mar 07, 2020 2:14 pm

I built the charcoal bin from expanded metal, flat bar and angle iron. A friend offered up use of his CNC plasma table so we cut the center divider with cut outs for a water pan and a drain from 1/2” plate. We also cut a bottom for the charcoal bin. 1/2” plate, shouldn’t be burning through it anytime soon.
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Re: Insulated Vertical Reverse Flow cabinet

Postby OldUsedParts » Sat Mar 07, 2020 2:49 pm

WOW ABOVE AND BEYOND :wav: :tup: :salut:

Beautiful Work, S&P :D
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