Bringing the discussion back on list if you don't mind...
Your smoker sounds very cool! When I get the time, I'd like to build
a big one like that.
Anyway, I've got a used medium green egg that I mostly smoke boston
butts on for bbq.
I'm using a 10 CFM blower w/ adapter plate (in the mail -- not
tested):
http://www.auberins.com/index.php?main_page=product_info&cPath=14&products_id=204
After reading your post, I think I could have gone smaller...
Your setup is very interesting with damper and motor control.
(I'm sure you know most of this, but I'll throw out what I've
researched for anyone else reading this)
Most of the ceramic smoker setups I've researched simply pulse the
motor.
They recommend to really close off the top of the smoker so smoke can
barely draft out.
(then a damper is not needed). Then the centrifugal motors motor
pulse for 0 to whatever seconds and then are off for so many seconds.
This pushes the smoke out the top and gives oxygen to the coals, then
it lets the meat sit in the heat and smoke with very little draft.
This also lets the motor is run at full voltage so the lifetime should
be good.
Your setup sounds pretty slick for metal smoker (I can't imagine how
much food you can get on there...)
I was hoping to have all the parts by the weekend, but I think it
might be next week -- I'll post an update and pics when I get it
going.
Even though we have different output requirements, it might be helpful
for anyone making one like yours if they had your PID Variables as a
starting point. I might use them as a start point (magnified by my
windowsize).
Thanks,
Jeb
On Jun 17, 12:43 am, Murl <
meas...@vtc.net> wrote:
> Hi, Jeb!
>
> Sorry, I tried to strike up a conversation on the Google group before I
> noticed your email.
>
> What kind of smoker are you controlling? How big is your blower? It sounds
> like we're doing similar things with different setups, so it'll be
> interesting to see how yours progresses.
>
> On mine, the only air intake I have is a single 3/4" pipe nipple welded into
> the side of the drum towards the bottom. I have a ball valve threaded onto
> the nipple, and a small blower attached to the valve. I read a blog
> somewhere that someone had used a 5cfm blower for his, so that's what I
> bought. When it came in, though, I thought for sure it was too small. I
> almost ordered a bigger one before even trying the one I bought. It turns
> out that 5cfm was plenty - in fact, I found that a lot of the time I was
> having to throttle back the ball valve in order to keep it from drafting
> through the blower and running too hot. Later, I built a dampner for the
> blower intake that's controlled by a servo connected to my controller. Now,
> I can do a 14+ hr smoke without adding charcoal or worrying too much about
> the temperature. When I first fire it up, it runs mostly off the dampner,
> then over time, the dampner ends up wide-open, and it controls off of the
> blower.
>
> So, the short version is that I'm not using a WindowSize, because I'm using
> analog outputs for both devices. The output range on the PID controller is
> 0-100%, with 0-50% being used for the dampner, and 50-100% being used for
> the fan. I'm still playing with the tuning a little, but that arrangement
> seems to be working pretty well.
>
> The only minimum I have is that I don't run the fan between 0-10% of full
> speed - but that's mainly to save the motor, since it starts sounding weird
> if I try to run it too slow.
>
> Please let me know if there's anything I can do to help you out. I'm also
> interested in hearing more about your smoker.
>
> Thanks!
>
> -Murl