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frankH · 02-22-2013, 04:07 PM

There are some expensive commercial smokers out there that can control fire temp separately from smoker temp, and that sounds like a great idea. I think lots of off flavors and the dreaded white smoke come from fires temps that are too low.

I have no idea how those smokers control temps, but here’s my plan for my gravity feed smoker. I’ve been planning this on and off for a year, and would appreciate any holes you can poke into my idea.

I’ll use my Stoker to operate a fan based on a high temp probe in the fire box to maintain my fire temp. A second probe will be in the smoking chamber which will maintain 225 degrees by opening or closing a bypass damper off the firebox.

Fire probe is low: Fan kicks on
Fire probe is high: Fan shuts off
Smoker probe is low: controller energizes actuator which closes bypass, directing heat/smoke to cook chamber
Smoker probe is high: controller de-energizes actuator, which allows a spring to open the damper on the bypass, directing the heat away from the cook chamber

I’ll have to find an actuator, and build a damper for the bypass.
I’ll need to buy a non-stoker probe that is rated for fire temps.
Unless they will sell me one separately, I’ll need to sacrifice a stoker fan, to connect the actuator to the Stoker with the appropriate connector/wire.
And I’ll need to tune the size of the fire box and by bypass in order to ensure the fan is on as much as possible.
Controller interaction may be an issue since two separate PID controllers will be interacting.

02-22-2013, 04:07 PM	#1
frankH On the road to being a farker Join Date: 02-25-12 Location: Overland Park, KS	My Updated Gravity Feed design There are some expensive commercial smokers out there that can control fire temp separately from smoker temp, and that sounds like a great idea. I think lots of off flavors and the dreaded white smoke come from fires temps that are too low. I have no idea how those smokers control temps, but here’s my plan for my gravity feed smoker. I’ve been planning this on and off for a year, and would appreciate any holes you can poke into my idea. I’ll use my Stoker to operate a fan based on a high temp probe in the fire box to maintain my fire temp. A second probe will be in the smoking chamber which will maintain 225 degrees by opening or closing a bypass damper off the firebox. Fire probe is low: Fan kicks on Fire probe is high: Fan shuts off Smoker probe is low: controller energizes actuator which closes bypass, directing heat/smoke to cook chamber Smoker probe is high: controller de-energizes actuator, which allows a spring to open the damper on the bypass, directing the heat away from the cook chamber I’ll have to find an actuator, and build a damper for the bypass. I’ll need to buy a non-stoker probe that is rated for fire temps. Unless they will sell me one separately, I’ll need to sacrifice a stoker fan, to connect the actuator to the Stoker with the appropriate connector/wire. And I’ll need to tune the size of the fire box and by bypass in order to ensure the fan is on as much as possible. Controller interaction may be an issue since two separate PID controllers will be interacting.