joseph
Junior Member
Posts: 66
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Post by joseph on Sept 10, 2014 16:11:15 GMT -8
I am trying to make something that works more or less like a conventional furnace - not something that operates in batch mode, or that requires constant attention. I am interested in the rocket design because of the efficiency.
I am more interested in a 4 inch or 6 inch stove that is constantly running at an even pace, than a larger stove that is fired intermittently.
I think that a rocket stove with an automatic feed would be the ideal stove.
By automatic feed, I am thinking of a design where the feed is mechanically assisted. I am not talking about cramming 8 hours worth of logs in a magazine and hoping they feed themselves without getting jammed. This type of approach will not work with real logs, which are not perfectly round or smooth.
The mechanical feed does not need to be electrically powered, but it does have to actually move the logs into position and load them one at a time into the burner. It would be powered by a wind-up type of mechanism.
Is anyone interested in a rocket stove with an automatic mechanical feed?
- joe
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Post by DCish on Sept 10, 2014 19:54:47 GMT -8
I had a similar idea some time back. I reviewed lots of different styles of stove to see what has been done. The main challenge to this as I see it is maintaining a burn area where airflow can be controlled to create a clean burn while still adding fuel sans human intervention. Solutions I've seen fall into several categories. 1) closed burn area where fuel is supplied on an ongoing basis. This I have only seen accomplished successfully through using fuel that is chopped up and fed through an auger or similar mechanism. Down side? chopping fuel takes energy, and fuel must fall within narrow parameters to avoid clogs (pellet stoves). That said, there are successful examples of self-feeding rocket pellet burners. 2) large batch loading with regulated burn such as an outdoor wood boiler. There are some clean-burning ones these days, but lots of electronics are involved. And 3) masonry or mass heaters. I have been sold on the mass heater design because of its relative simplicity compared to the other designs. It is an exceptionally clean burning device with wide-ranging DIY possibilities. If you have ideas for a mechanized fuel feed, I would love to see some sketches, but my degree of hope for successful implementation is low after getting to know just how many variables must be managed in order to achieve a clean burn.
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
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Post by morticcio on Sept 11, 2014 2:55:19 GMT -8
You're on a hiding to nothing in my opinion. Too complicated and too many points of failure. A design where the feed is mechanically assisted, which moves the logs into position and loads them one at a time into the burner will get jammed too! How does the feed mechanism know when to load a log? What if the fire is low and the next log smothers it? Like you said, logs are not perfectly round or smooth.
I prefer loading logs in my stoves manually for two reasons - it is simple and safe!
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Post by Daryl on Sept 11, 2014 4:41:50 GMT -8
I have seen something similar on youtube but with a different type of stove. I think it was pellets too. Good luck to you in whatever direction you choose. I hope you keep us updated and post your adventures here.
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joseph
Junior Member
Posts: 66
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Post by joseph on Sept 11, 2014 5:36:17 GMT -8
You're on a hiding to nothing in my opinion. Too complicated and too many points of failure. A design where the feed is mechanically assisted, which moves the logs into position and loads them one at a time into the burner will get jammed too! How does the feed mechanism know when to load a log? What if the fire is low and the next log smothers it? Like you said, logs are not perfectly round or smooth. I prefer loading logs in my stoves manually for two reasons - it is simple and safe! My design is supposed to handle those problems. As for being complicated: that's a compromise. It was be as simple as it can be to get the job done, but if it was too simple, it would not work. - joe
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joseph
Junior Member
Posts: 66
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Post by joseph on Sept 11, 2014 5:42:27 GMT -8
I had a similar idea some time back. I reviewed lots of different styles of stove to see what has been done. The main challenge to this as I see it is maintaining a burn area where airflow can be controlled to create a clean burn while still adding fuel sans human intervention. Solutions I've seen fall into several categories. 1) closed burn area where fuel is supplied on an ongoing basis. This I have only seen accomplished successfully through using fuel that is chopped up and fed through an auger or similar mechanism. Down side? chopping fuel takes energy, and fuel must fall within narrow parameters to avoid clogs (pellet stoves). That said, there are successful examples of self-feeding rocket pellet burners. 2) large batch loading with regulated burn such as an outdoor wood boiler. There are some clean-burning ones these days, but lots of electronics are involved. And 3) masonry or mass heaters. I have been sold on the mass heater design because of its relative simplicity compared to the other designs. It is an exceptionally clean burning device with wide-ranging DIY possibilities. If you have ideas for a mechanized fuel feed, I would love to see some sketches, but my degree of hope for successful implementation is low after getting to know just how many variables must be managed in order to achieve a clean burn. The rocket stove itself, which will be the standard "J" design, will not be modified. The feed mechanism will be external to the stove and will feed the logs into the "J" tube in a way similiar to how a person would feed it. - joe
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Post by DCish on Sept 11, 2014 9:40:06 GMT -8
I look forward to seeing your experiments and results, it promises to be an intriguing exploration.
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Post by dancyn on Sept 14, 2014 7:29:58 GMT -8
Hi joseph, I too have been considering the issue of continual feed-tube loading, and the only way via gravity feed with out possible hanging-up would be to have a slightly angled feed tube, so that the wood does not bind or ride over each other. the ends would have to be squared off to prevent them from over-riding each other as they slowly slide down the feed tube. Round feed tube would have less chance of friction/binding and may be a 10 to 15 degree slope off of vertical.
Just a thought & plan ..... Cheers, Dan.
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joseph
Junior Member
Posts: 66
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Post by joseph on Sept 14, 2014 9:16:57 GMT -8
Hi joseph, I too have been considering the issue of continual feed-tube loading, and the only way via gravity feed with out possible hanging-up would be to have a slightly angled feed tube, so that the wood does not bind or ride over each other. the ends would have to be squared off to prevent them from over-riding each other as they slowly slide down the feed tube. Round feed tube would have less chance of friction/binding and may be a 10 to 15 degree slope off of vertical. Just a thought & plan ..... Cheers, Dan. I do not believe that a simple gravity feed will work successfully with tree wood. It will only work with pellets, or some other form of processed wood of uniform size. I do not believe continuous loading will work either, because of "flame creep" - the fire will try to go up the feed tube. This is why the system I am proposing has an actual feed mechanism, a mechanical device that places the logs in the feed chamber, and only at the appropriate time. It is separate from the feed tube, so that the rocket stove itself is not altered, nor are there problems with "flame creep" and such. - joe
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Sept 15, 2014 10:57:30 GMT -8
How will the mechanical device know when it is appropriate to place the logs in the feed chamber?
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joseph
Junior Member
Posts: 66
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Post by joseph on Sept 15, 2014 12:11:19 GMT -8
How will the mechanical device know when it is appropriate to place the logs in the feed chamber? The logs stand vertically in the J-tube. They burn first at the bottom, and then become shorter as they burn. The loading device will have an "arm" that "feels" if the top of the log is still above a certain height; if not, it will insert another log. Note that the "log" could actually be a bundle of sticks, or a bundle of two smaller logs. Each "log" is held separately in the magazine, so that they do not jam. - joe
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Post by ericvw on Sept 15, 2014 14:28:32 GMT -8
Hey Joe, Nice idea, if not a little lofty, in my opinion. Still, if you can come up with a working model I would love to see it! New ideas are often met with skepticism, I'm one of those, too- BUT, you could turn the whole thing on its head. Keep after it Joe and here's to more feasibility questions! Eric VW
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joseph
Junior Member
Posts: 66
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Post by joseph on Sept 16, 2014 16:31:30 GMT -8
Hey Joe, Nice idea, if not a little lofty, in my opinion. Still, if you can come up with a working model I would love to see it! New ideas are often met with skepticism, I'm one of those, too- BUT, you could turn the whole thing on its head. Keep after it Joe and here's to more feasibility questions! Eric VW Thanks for your interest and encouragement. If I made it, would you actually use it? - joe
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Post by ericvw on Sept 16, 2014 17:35:08 GMT -8
Hi Joe, Would I use it? Since I'm embarking on a batch box journey for our heater I would say right off- no. But nonetheless no one should or will stop you verbally here... To see such an innovation could be an exciting thing! So you want to use a magazine(or multiple ones?)- what sort of other mechanized action were you thinking? Please provide some kind of sketch or rendering of this proposal for the folks to be able to chime in more. Altho, if you're a mad scientist type, you may end up just posting a picture or vid at the tail end of completion! Either way, if there's anyway I can lend a mental hand- just holler. Eric VW
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joseph
Junior Member
Posts: 66
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Post by joseph on Sept 17, 2014 9:09:57 GMT -8
Hi Joe, Would I use it? Since I'm embarking on a batch box journey for our heater I would say right off- no. But nonetheless no one should or will stop you verbally here... To see such an innovation could be an exciting thing! So you want to use a magazine(or multiple ones?)- what sort of other mechanized action were you thinking? Please provide some kind of sketch or rendering of this proposal for the folks to be able to chime in more. Altho, if you're a mad scientist type, you may end up just posting a picture or vid at the tail end of completion! Either way, if there's anyway I can lend a mental hand- just holler. Eric VW The magazine would hold 12 logs, each up to 4 inches (10 cm) in diameter, in separate compartments. I could make it hold more, or bigger, but then the whole unit would be larger, and take up more room. The principle of operation would work on a larger model. Each "log" could actually be a bundle of sticks, or two smaller logs. What I need right now is not help in mechanical engineering but for people to answer two basic questions: 1) Would you find such a device useful? 2) In your experience with a "J" tube, assuming that there are already coals and the system is up to temperature, how does it perform for burning logs? Or does it only work well for burning sticks?
- joe
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