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Post by painterd on Feb 25, 2015 17:34:16 GMT -8
After seeing some of the camping/tent stoves on the market, I noticed some have a pellet feed option. After seeing the reviews on how well it works, I decided to see if I could incorporate that idea with my wood furnace in the basement. I have a 4" burn tube and stainless steel burner I am going to use on my shop rocket stove after I pour the riser and burn chamber, so I decided to see how well it would work on my wood furnace. I had to build another door for the furnace to be able to mount my burn tube into (didn't want to cut up the existing door) amd mount a small hopper above it to see just how well it would work. I've always had a fairly good draw of air up my chimney, but would it be enough to keep the pellets burning and make a sufficient amount of heat to make the fan kick in?
So now the moment of truth...I fired up the pellets. he draw is sufficient enough to get them going, and after 10 minutes or so, I started to hear that familiar sound of a rocket stove! Success! The temp started to climb and leveled off at 400 degrees. Perfect. The fan started and is now blowing 95 degree air up to the main level of our home, just right. The stove pipe is running right at 150 degrees and there is absolutely NO smoke coming out of the chimney, just a wisp of heat wave is all I can see. I can't believe how well it works!
My hopper (only made for experimenting) only holds about 1/2 of a 40 lb. bag of pellets and I'll soon see how long that lasts. The secondary air, which is a 1"X3" square tube that introduces air just ahead of the burner to gasify the pellet smoke. It's blasting out a nice blue flame right now. I guess time will tell if burning pellets is the way to go. Anyway, it's an option I can always use if need be.
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Post by ronyon on Feb 25, 2015 22:58:04 GMT -8
Pictures? Pretty please!
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Post by painterd on Feb 26, 2015 6:10:09 GMT -8
I'll be working on the hopper today to make it larger to hold more pellets. Then I'm going to do some experimenting with different burners I've made for my shop stove. I'll try to get some photos up later today if I get the time. My burn tube and pellet feed is simple a 4" square tube, 12" long, with a 3-1/2" tube mounted at a 30 degree angle to feed the pellets into the burner. The burner is just 1/4" stainless steel rods welded 1/4" apart about 5" long with them angled up in the rear for the pellets to slide down. There's a 1/4" gap under the burner so the primary air can travel under it, keeping the pellets burning. The secondary air is just a 1" ramp inside the feed tube, where I welded a plate inside for air to travel down, and burn the gas off the pellets. I made a door on the back of the burn tube to light the pellets, and a 2"X4" opening on the top of the tube (between the door and feed tube, so I can close the door and keep intake air coming in behind the burner. I can run it with the door open, but there's always that chance of a stray pellet coming out of the door opening. I've had it happen in my shop stove and I surely don't want to see it happen in my house!
The secondary air is a blue flame blasting off the pellets before it comes out the tube into the stove. I cracked the door open as it was burning to see it in action, but opening the door slows the draw down and the flame starts to turn yellow. I may have to put a small window in the door to see it while it's running with different burner configurations. I have a large piece of ceramic glass out of an old oven I can cut a piece out of for a small window. Looks like I'll be busy today...again!
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Post by painterd on Mar 3, 2015 2:12:27 GMT -8
Update,
I did some testing with a couple other pellet burnings I made to see what kind of heat I'd get out of them. I also installed a 4" window in the door so I could observe the flame patterns with various burners and air controls. Now I can see what's happening in there. I actually got a hotter flame out of a smaller burner if that makes sense. It seems there is more air passing by the smaller burner and the flame is hotter. Also, I shut off the air feed that passes just ahead of the pellets, because it seems it burns very hot just ahead of the pellets (turns the burn tube red hot!) but the stove doesn't get as hot that way. So I just use the primary air in back of the pellet burner, which gives it about a 1 foot flame and heats up the stove better. Now I'm getting 450 degrees in the stove and the blowing is putting out 100 degree air to the upper rooms of my house. Actually that's a little too hot, but I can cut the primary air down to about 1/4 and it runs perfect. I get 12 hours of heat out of a 40 lb. bag of pellets now. And the ash is so minimal, I'd only have to pull the ash pan out about once a month if that. I'm not sure if I will burn pellets all season, but it's nice knowing that it works very well and always is an option. With pellets at $219 for a 50 bag pallet of pellets, I may just keep one in the wood room just for those long winter nights when it dips down way below zero.
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