Hello all,
I thought I would share my recent build of a servo controlled damper based off of the Auber Instruments Blower assembly. The Auber blower assembly has a free floating damper that opens and closes with airflow. This system works fine with the Auber controllers because they pulse the fan full on and off with an adjustable duty cycle measured in seconds. When I used this blower with the HeaterMeter, I encountered occasional thermal runaway due to the flapper hanging partially open, despite the fan cycling off. I reasoned the gentle action of the lower fan RPM allowed the flapper to somehow wedge in place and then failed to close as the fan gradually reduced it's RPM.
As a solution, I thought I would try to manually control the opening and closing of the flapper valve using the servo control provided by the HeaterMeter. I just finished the assembly tonight, so I haven't had time to do a long cook yet, but I couldn't wait to share the results. Including the servo, I have less than $20 in parts and it took just a few hours to build. I used a simple RJ45 splitter epoxied to the top plate so I could have separate cables for the servo and the fan in case I need to replace one or the other in the future. The actuator arms that came with the servos were not long enough for my geometry, so I fabbed a small arm from stainless and glued and screwed it to one of the arms that came with the servo. If I were to do this again, I would use an even longer arm to improve the geometry and lessen the servo rotation accordingly.
Mike
I thought I would share my recent build of a servo controlled damper based off of the Auber Instruments Blower assembly. The Auber blower assembly has a free floating damper that opens and closes with airflow. This system works fine with the Auber controllers because they pulse the fan full on and off with an adjustable duty cycle measured in seconds. When I used this blower with the HeaterMeter, I encountered occasional thermal runaway due to the flapper hanging partially open, despite the fan cycling off. I reasoned the gentle action of the lower fan RPM allowed the flapper to somehow wedge in place and then failed to close as the fan gradually reduced it's RPM.
As a solution, I thought I would try to manually control the opening and closing of the flapper valve using the servo control provided by the HeaterMeter. I just finished the assembly tonight, so I haven't had time to do a long cook yet, but I couldn't wait to share the results. Including the servo, I have less than $20 in parts and it took just a few hours to build. I used a simple RJ45 splitter epoxied to the top plate so I could have separate cables for the servo and the fan in case I need to replace one or the other in the future. The actuator arms that came with the servos were not long enough for my geometry, so I fabbed a small arm from stainless and glued and screwed it to one of the arms that came with the servo. If I were to do this again, I would use an even longer arm to improve the geometry and lessen the servo rotation accordingly.
Mike
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