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Post by satamax on Jan 13, 2016 13:23:47 GMT -8
Hi everybody. I have that flap gate from a chimney, at the end of the bell of my latest build. I would like to find a way to automaticaly close it at the end of a burn. It is actioned by a push pull lever. Pushing would close it. Does anybody have an idea on how i could do the automated closing. Thanks a lot. Max.
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Post by josephcrawley on Jan 13, 2016 13:51:45 GMT -8
How about a temperature based relay that is on the chimney?
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Post by matthewwalker on Jan 13, 2016 16:58:24 GMT -8
Max, check out automatic linear actuators for ventilating greenhouses. They are meant to open a vent via pushing motion when temps rise above a certain point. It would probably be just about right to close when things cooled to that temp, but I'm not sure how strong the pull is compared to the push. I believe they are hydraulic cylinders filled with wax or something with an appropriate freeze point, so they should be equally strong in both directions, maybe? I have no experience with them.
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Post by satamax on Jan 14, 2016 0:35:22 GMT -8
Well well well. Josephcrawley, I don't see the point of the relay with a temp sensor in the chimney. May be a CO/CO2 sensor, yep. Matt, I will check thoses. Seems hard to implement. May be the simpler solution, a webcam facing the door. When there's no embers anymore, I trigger an electromagnet, via my smartphone Or else, a photoresistor, with a circuit, which would power the actuator when there's no light left. Or a thermostat.
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kpl
New Member
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Post by kpl on Jan 14, 2016 4:36:31 GMT -8
For thermostat you'd need the sensor to be located under the firebox floor, so it could detect when burning is really ended. It would need some delay too, but firebox floor would provide some delay by itself because of heat mass. It should be easy to build for anybody who is familiar with electronics, nothing really difficult. Would need to place a K-type thermocouple in the stove though, and get the wiring out.
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Post by Vortex on Jan 14, 2016 5:24:59 GMT -8
Many years ago I saw a huge wood fired central heating boiler in the basement of an old building. The firebox was 3 feet wide and 6 feet deep. It had primary and secondary air vents controlled by bi-metal coil springs with chains attached to the air flaps. The springs were made of two different metals bonded together, so one side expands at a different rate to the other, which causes the spring to unwind or wind up depending on the temperature, and so pull the chain and open the flap or release it and close the flap. No idea if you can still get them.
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kpl
New Member
Posts: 47
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Post by kpl on Jan 14, 2016 5:31:14 GMT -8
You can, but in this case you need to read a temperature quite far away from the flap you need to close. I'm not sure chimney temperature would be good parameter to use. Bimetal spring would be easy then.
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Post by independentenergy on Jan 14, 2016 9:57:04 GMT -8
I use a bypass to control a linear actuator controlled by Arduino with a thermocouple K connected to the chimney, when T set is exceeded automatically closes the bypass. for what you need to do, as you have already said, you should use an IR sensor on the door to detect a flame, in order to close the valve only when the fire is really off video
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