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smootz BBQ Super Fan
Joined: 12 Nov 2011 Posts: 451 Location: Kitts Hill, Ohio
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Posted: Wed Nov 30 16 9:33 am Post subject: Automatic draft control "flapper" |
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A few years ago I saw a very simple but very effective automatic draft control on a large propane tank based stick burner. Unfortunately it was at a bbq restaurant and I could not see or obtain much information.
The whole setup was homemade. It consisted of some sort of oven thermometer wired to a solenoid actuator. The actuator pulled a wire that opened and closed a "flap" style vent on the fire box.
It was super simple but worked very well. I watched it open and close several times. BTW - the BBQ was great!
It would be easily fabricated if i could find a thermostat that would work within smoker temp ranges to send a signal to the solenoid.
Is there a reason why blowers are typically used instead of automatic dampers? _________________ 150 gallon vertical
propane pig
180 RF |
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biker.chef BBQ Pro

Joined: 28 Jun 2010 Posts: 558 Location: Burnsville Minnesota
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Posted: Wed Nov 30 16 9:47 am Post subject: Re: Automatic draft control "flapper" |
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smootz wrote: |
Is there a reason why blowers are typically used instead of automatic dampers? |
Blowers are simple to use and they are easy to couple to PID controller.
A PID is either fan on or fan off. No fan speed adjustments or
partially opening a damper.
I guess that an advantage of the mechanical system. _________________ -------
Every Day, Thousands Of Innocent Plants Are Killed By Vegetarians.
Help End The Violence.
EAT BACON |
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k.a.m. BBQ Mega Star

Joined: 12 Dec 2007 Posts: 26012 Location: Southeast Texas.
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Posted: Wed Nov 30 16 7:36 pm Post subject: |
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On typical draft controllers blowers are used on the intake to force air into the firebox or stop the flow completely. The flapper you're describing sounds like what J&R Oylers use to control the temps in their rotisseries. _________________ Always remember slow and steady wins the race.
Hybrid Cooker |
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smootz BBQ Super Fan
Joined: 12 Nov 2011 Posts: 451 Location: Kitts Hill, Ohio
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Posted: Thu Dec 01 16 3:39 am Post subject: |
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I briefly looked into this a few years back. The system is super simple and could be easily fabricated if I could find the right kind of thermostat control. It may be as simple as the thermostat from an old kitchen oven. All I need is something that will trip a solenoid actuator. Just "on-off". Trap door is either open or closed, nothing variable or progressive. _________________ 150 gallon vertical
propane pig
180 RF |
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animal BBQ Pro
Joined: 05 Nov 2007 Posts: 935 Location: Wisconsin
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smootz BBQ Super Fan
Joined: 12 Nov 2011 Posts: 451 Location: Kitts Hill, Ohio
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Posted: Thu Dec 01 16 7:20 am Post subject: |
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That is a cute little unit but not exactly what I am looking for. I need something that will react to the temperature in the cooking chamber and give me an electric impulse (preferably 12 volt) that would open or close a simple solenoid actuator. The actuator is connected by a wire or lever to open and close the flapper door on the firebox. _________________ 150 gallon vertical
propane pig
180 RF |
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biker.chef BBQ Pro

Joined: 28 Jun 2010 Posts: 558 Location: Burnsville Minnesota
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Posted: Thu Dec 01 16 7:26 am Post subject: |
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A BBQ Guru or a PID off Ebay would do the job nicely.
More bucks it would give you a set it and forget it controler. _________________ -------
Every Day, Thousands Of Innocent Plants Are Killed By Vegetarians.
Help End The Violence.
EAT BACON |
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smootz BBQ Super Fan
Joined: 12 Nov 2011 Posts: 451 Location: Kitts Hill, Ohio
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Posted: Thu Dec 01 16 8:49 am Post subject: |
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If everyone is using blowers instead of flappers there must be a reason. I need to lurk for a while and get educated on PID. (Not sure what that stands for). _________________ 150 gallon vertical
propane pig
180 RF |
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jess BBQ Super Pro
Joined: 26 Sep 2007 Posts: 1826 Location: Fl.
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Posted: Thu Dec 01 16 6:38 pm Post subject: |
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proportional-integral - derivative controller..
And with that said I bet most people still do not
know what that means...  |
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smootz BBQ Super Fan
Joined: 12 Nov 2011 Posts: 451 Location: Kitts Hill, Ohio
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Posted: Fri Dec 02 16 1:56 am Post subject: |
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jess wrote: | proportional-integral - derivative controller..
And with that said I bet most people still do not
know what that means...  |
It sounds like it is more than "on-off". I am guessing the blowers like Stoker and Guru are variable speed depending on need? Sorry for the total ignorance. No one I know has anything like that for me to see. _________________ 150 gallon vertical
propane pig
180 RF |
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k.a.m. BBQ Mega Star

Joined: 12 Dec 2007 Posts: 26012 Location: Southeast Texas.
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Posted: Fri Dec 02 16 3:52 am Post subject: |
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This one has been getting some good reviews on the competition trail. I watched this business grow from a go fund me account.
http://theperfectdraft.com/ _________________ Always remember slow and steady wins the race.
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biker.chef BBQ Pro

Joined: 28 Jun 2010 Posts: 558 Location: Burnsville Minnesota
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Posted: Fri Dec 02 16 4:03 am Post subject: |
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I've not used a guru but I don't think it is variable speed.
My controller will pulse the fan. Short bursts of on/off.
I did a posting a few years ago about a DYI PID. I can try to
find it. But if your not familiar with wiring your best sticking
with with a commercial solution.
The advantage of an electronic controller is that that homes in on the
desired temperature. As the smoker gets to set temperature the controller
will start pulsing the fan so it doesn't over shoot the temp.
As it senses the smoker is cooling off it will start the fan again.
It "learns" over time and keeps the smoker at constant temperature.
A mechanical thermostat will keep the air flow open until the
smoker is at temperature. The fire is still hot so the temp will rise well
past the desired temperature. It will close down until the smoker has
cooled past the turn on temperature.
So the problem is you will get spikes and dips in temperatures _________________ -------
Every Day, Thousands Of Innocent Plants Are Killed By Vegetarians.
Help End The Violence.
EAT BACON |
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PaleAle BBQ Fan

Joined: 17 Apr 2011 Posts: 210 Location: Colonial Heights, VA
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Posted: Fri Dec 02 16 6:45 am Post subject: |
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Depends on your DIY skills you can look into heater meter. I love mine!!!! |
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RodinBangkok BBQ Super Fan

Joined: 30 Dec 2006 Posts: 491 Location: Bangkok Thailand
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Posted: Fri Dec 02 16 7:29 pm Post subject: |
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Take a look at using an Arduino controller with a servo to control a butterfly valve on your exhaust, it can also easily control the intake fan via PID software. Probably won't cost you more than $50 bucks if you have some tinkering skills. _________________ Rod |
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mbellot BBQ Super Fan
Joined: 16 Aug 2010 Posts: 425 Location: Illinois
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Posted: Fri Dec 02 16 11:07 pm Post subject: |
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I've used one from Auber with good success on a couple different smokers/grills. I even played with it and some homebrew electronics (SSR) to make a crockpot sous vide setup.
The one thing I found with the Auber (maybe all PID controllers, not sure) is that you are better off getting close to your target temperature (50F or so) before engaging the control, otherwise the blower will tend to ramp the fire up too high and you end up with an overshoot that risks snuffing your fire when it's trying to bring the temperature back down. |
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biker.chef BBQ Pro

Joined: 28 Jun 2010 Posts: 558 Location: Burnsville Minnesota
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Posted: Fri Dec 02 16 11:35 pm Post subject: |
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mbellot wrote: |
The one thing I found with the Auber (maybe all PID controllers, not sure) is that you are better off getting close to your target temperature (50F or so) before engaging the control, otherwise the blower will tend to ramp the fire up too high and you end up with an overshoot that risks snuffing your fire when it's trying to bring the temperature back down. |
I don't have that problem. I think it maybe it's a function of the smoker.
Mine is a small vertical smoker so the fire is small too. _________________ -------
Every Day, Thousands Of Innocent Plants Are Killed By Vegetarians.
Help End The Violence.
EAT BACON |
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smootz BBQ Super Fan
Joined: 12 Nov 2011 Posts: 451 Location: Kitts Hill, Ohio
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Posted: Sat Dec 03 16 11:31 pm Post subject: |
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biker.chef wrote: |
A mechanical thermostat will keep the air flow open until the
smoker is at temperature. The fire is still hot so the temp will rise well
past the desired temperature. It will close down until the smoker has
cooled past the turn on temperature.
So the problem is you will get spikes and dips in temperatures |
Best explaination I have heard. Thanks. This is a winter project so I will start researching DIY blower setups. The one KAM mentioned looks pretty good too. _________________ 150 gallon vertical
propane pig
180 RF |
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