Conversion of a hand feed to a stoker.

PostBy: LsFarm On: Fri Feb 02, 2007 10:53 pm

I have noticed some unburnt coal in the ash from the stoker unit. Maybe 10-20%. I decided to add a steel ring around the outside of the firepot to increase the area that the coal can burn on before it drops into the ash pan. There is a ring of combustion air vents around the outside of the firepot, I positioned the ring just below this row of vents.

I'm really surprised by how much larger the fire area is without any increase in the feed rate or quantity. I am guessing because it is hard to measure the diameter of the red-hot fire, but It appears to have increased from about 9-10" diameter before the ring was added to about 12-14" diameter now. The outside diameter of the ring is 18", the outside of the firepot 13".

Since the area of the burning coal determines the heat output of the firebed, I should be getting a significant increase in heat without feeding more coal to the fire.

I'll soon know if the stoker can keep up with the subzero weather this weekend.

Greg L
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firepot.jpg
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The steel ring rides just below the row of air vents you can see on the outside of the firepot. The outside diameter of the pot is 13", the ring's width is 2.5" wide, 18" outer diameter
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Here is the firepot with the outer ring installed, the flash washes out a lot of the red from the burning anthracite coal, but the larger diameter of the whole surface is clear.
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This is the same shot without the flash. the larger diameter of the burning coal is clear. The rice anthracite coal burns to a soft almost powdery ash now.
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Last edited by LsFarm on Mon Feb 12, 2007 12:52 am, edited 4 times in total.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: tewplanman On: Fri Feb 02, 2007 10:59 pm

Have you tried starting anthracite using matchlight or plain soft coal like charcole??

Tom
tewplanman
 

PostBy: LsFarm On: Fri Feb 02, 2007 11:44 pm

Hi Tom, I haven't tried either, I always use a wood fire in a hand load, a piece of a road flare for my Iron Fireman stoker or an oxy-acetylene torch for the LeisureLine Stoker stoves in the shop.

For your furnace I'd recommend a big hot wood fire, since the firebed is so large. Then slowly load on several thin layers of coal and add each new layer as the previous one gets burning.

Greg L.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Visit Lehigh Anthracite

PostBy: Yanche On: Sat Feb 03, 2007 12:20 am

Are the fire photos with the ring using anthracite or bituminous?

Yanche
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Stoker with ring

PostBy: BigBarney On: Sat Feb 03, 2007 12:31 am

When you burned with the additional ring around the retort what type of coal did you use,and size? What feed rate?

Have you tried it with the bituminous coal ?

When the coal formed a high mound in the pot did you have sized coal
either buckwheat or pea?

Looks like a really strong fire this time should be able to get a good test
this weekend when we have cold temperatures.


Ted BigBarney
BigBarney
 

PostBy: LsFarm On: Sat Feb 03, 2007 4:43 am

I have completely given up on burning bituminous in the stoker. So all three photos are with Rice Anthracite. The Rice anthracite makes a soft pillow of burning coal. The fire in the center is the youngest and around the edge of the added ring is the most mature fire.

The feed rate I've been using is the middle one, ~20# per hour, but the timer I have installed between the aquastat and the stoker motor is set to run 15 minutes on, 15 minutes off. So any time the aquastat is calling for heat, the maximum feed would be 10# per hour. When the timer is in the off mode, the added electric combustion fan is still running, so the coal in the burn pot is still getting alot of air, the flames off the pot are still 8-10" high during the off mode.

When the weather warms up again I'll set the feed rate to 10# per hour, and set the timer to something like 10 min. on/20 min. off. I have a lot of experimenting to do.

I only have Rice anthracite in any quantity. I'd like to try buckwheat size, but can't find it anywhere. I do have about 40# of Pea anthracite. but I don't think the Pea size will be in the pot long enough to burn completely. I may try adding a handfull to the center of the fire, and watch it to see if it will burn completely.

I added a double handfull of Bitum coal [rice/pea size] to the center of the fire yesterday, it fused into a lump and this lump slowly migrated to the edge of the burning anthracite coal, sort of like a boat floating on water. The lump was still in one piece when it fell off the edge of the pot into the ashpan.

Right now it is about 0335 on Saturday morning, the outside air temp is -2*, the aquastat is not calling for heat [I have a light in the circuit I can see from the house] and the house is still nice and warm. The aquastat seems to call for heat only about 15-30 minutes an hour. But this is not something I have tracked closely. I can't see the boiler building from any windows of the house except the kitchen and dining room. So I have not sat or stood at the window to watch the light cycle on/off.

I'm pretty happy with the results so far. I'm hoping to see a more completely burnt ash in the ash pan later this morning when I go out to take a look and empty the ashpan for the day.

Does anyone have experience burning buckwheat size instead of Rice size coal in their stoker [any flavor stoker] ?

Greg L

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Last edited by LsFarm on Mon Feb 12, 2007 12:49 am, edited 2 times in total.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: europachris On: Sat Feb 03, 2007 9:00 am

That's really sweet, Greg. It appears you've got your setup NAILED! It would appear that you are DONE with hand feeding.

Chris
europachris
 
Stove/Furnace Make: EFM 350/Iron Fireman
Stove/Furnace Model: Custom bituminous burner

PostBy: LsFarm On: Sat Feb 03, 2007 9:17 am

Almost done Chris. I have about 5-700# of Stove/Nut mix anthracite and about 1000# of Bituminous in the coal bin. I have to make room for rice coal so I'll probably convert back to hand feed in the next week and burn up the remaining Anthracite, and clean out that half of the coal bin.

I want to run the stoker through at least part of this cold spell to see how it does keeping up with high demand and watch the coal comsumption. So far it appears that I still burn about the same quantity of coal per day as with the hand feed operation.

Greg L
Last edited by LsFarm on Mon Feb 12, 2007 12:54 am, edited 1 time in total.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: europachris On: Sat Feb 03, 2007 9:43 am

Nice! I'm going to see if I can get enough interest here between now and next fall to bring in a semi-dump of rice at our local dealer. He has bagged coal for a 'reasonable' price for bagged, but expressed interest in going bulk next year if the demand is there.

He said there were people coming out from the Chicago 'burbs, up in Wisconsin, etc. to buy anthracite, and a lot of it was nut size. Evidently there are more people than I thought looking for a supply of anthracite around here. Who knows, maybe Rockford will become the 'anthracite capital of the Midwest'? I definitely think if he brought in a truck of nut and a truck of rice that he would be able to move it easily.

He had several pellet stoves, a corn stove, and the DVC-500 running in the showroom. The DVC-500 was kicking all the other stove's butts for heat output. He uses it to keep the shop warm over Sundays when they are closed. All the other stoves would run out of fuel trying to heat the place that long. The coal stove could handle it easily.

Chris
europachris
 
Stove/Furnace Make: EFM 350/Iron Fireman
Stove/Furnace Model: Custom bituminous burner

PostBy: Yanche On: Sat Feb 03, 2007 11:51 am

Greg,

Just buy a load of bagged anthracite yourself direct from the processor.

Check: http://www.penncoal.com/wst_page10.html

You could likely pre-sell what you don't need and just have people drive to your farm to pick it up.

Yanche
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

PostBy: LsFarm On: Sun Feb 04, 2007 12:49 pm

Cold weather update: The stoker is doing very well. With the added area around the firepot rim, I'm getting a much more complete burn of the coal. The added area of burning coal extending out on the perimeter ring is increasing the heat output because the coal can burn much longer before falling off into the ashpan.

The boiler maintained 150* water temp all night, appeared to have burn about 80# of coal, the ash pan about 2/3 full, not bad for 12 hours of burning in -10* weather with a wind. I don't believe my hand fed fire would have maintained the water temps after 10 hours. Gotta love a stoker.

I have noticed one slight issue that I will take care of soon. The steel ring I added is about 1" below the top lip of the firepot. This is so that the ring is below the row of air vents feeding the fire on the ring. The bed of burning coal is very fragile, it doesn't take much to disrupt the air flow through the loose pieces of rice coal. What is happening is the burning bed of coal fractures when it goes over the lip of the pot and drops onto the steel ring. Once the ash builds up on the ring then the burning coal bed stays more intact and expands in area instead of fracturing.

After looking at the EFM style burnpot, I've decided that I need to bring the steel ring up level with the top lip of the pot, so the coal bed will stay intact as it is pushed out onto a level lip like the EFM firepot. The trick is going to be to channel the air from the outer ring of combustion air vents up to a steel plate 1" above the vents. I have a plan and materials. I'll post a photo when done, rather than trying to describe it here.

So I'm going to pull the stoker out, and fire up a hand feed fire, to burn up the remaining nut/stove coal mix. this will also make room in the coal bin for a load of rice and or buckwheat coal.

I'm not real excited about making another hand fed fire but I do need to use up the remaining coal. I'm really enjoying the stoker doing so much work for me. :) :lol:

Greg L

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lowerring.jpg
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Here you can see the rice coal in the pot, and the 1"+ drop to the single lower ring, I placed this ring here to expose the air vents to the coal, but the hot coal went out once it fractured and fell onto the ring.
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topring.jpg
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Here is the top ring I'm adding. It is pretty much level with the top of the burn pot. The burning 'pancake' of coal should not fracture when it moves onto this level ring.
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Here are the upper and lower rings, the chamber between will be pressurized by the air vents. I'll wrap the perimeter with a strip of steel to enclose the air chamber.
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Last edited by LsFarm on Mon Feb 12, 2007 12:59 am, edited 2 times in total.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: LsFarm On: Tue Feb 06, 2007 11:36 pm

I enclosed the open perimeter of the two rings with a piece of 14 gauge steel, This traps the combustion air from the ring of vents on the outside of the burn pot.

Please don't be critical of my welding, I just had cataract surgery last week and my close vision is really bad. Even with various powers of reading glasses I can't see well enough up close to do decent looking welds. The appearance of the welds is embarassing, but they hold the strip of steel on, and will be covered in ashes, so they will do. If I find the slight raised lip to be a problem I'll grind it off and fix the welds.

Next I drilled two rings of 1/8" diameter holes to let the combustion air up through the bottom of the hot bed or rice coal.

The unmodified firepot gives me a 9" diameter bed of red, burning coal. so the burning area is 4.5" squared is 20.25 x 3.14=63.5 square inches of burning coal

If I get a 14" diameter burning bed of coal out onto the ring. the ring outer diameter is 18", I will then have:

7"squared is 49 x 3.14=153.9 square inches of burning coal, more than double the burning area and heat. If I only get a 13" diameter burning bed it will still be double the area of the unmodified burn pot.

I'll not be putting the stoker back in the boiler untill I have burnt up my remaining supply of stove/nut anthracite, I have to empty that side of the coal bin to make room for several tons of rice or buckwheat coal.

Hope you found this intersting

greg L
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boxedring.jpg
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here you can see the boxed in double rings with the lousy welds. You can see that the coal bed will be able to move out onto the ring without much interferance.
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Here is the inside of the boxed in rings showing the two rings of combustion air holes.
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Last edited by LsFarm on Sun Feb 11, 2007 9:09 pm, edited 2 times in total.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: europachris On: Tue Feb 06, 2007 11:49 pm

Looks real nice, Greg. Can't wait to read the results of the new mods!

Burn, baybee, burn!

Chris
europachris
 
Stove/Furnace Make: EFM 350/Iron Fireman
Stove/Furnace Model: Custom bituminous burner

PostBy: LsFarm On: Sun Feb 11, 2007 9:52 pm

I finished burning my stove/nut anthracite this morning, and have converted to using my Iron Fireman underfeed stoker.

The last time I used the stoker, I had added an outer ring to the original firepot to increase area of the burning coal. Without the ring, there was a lot of unburnt coal and burning coals falling off the pot into the ashpan. With the added ring, I was able to get a larger diameter fire, but it had problems. The drop from the top of the firepot onto the ring was about 1.25", when the burning coal bed dropped off the edge, the bed fractured, and the fire went out in the coal on the ring..

With the new ring with an air chamber to catch the air from the outer air vents, I have a level surface for the burning 'pancake' of coal to expand onto without fracturing. I have a much larger diameter 'pancake' of burning coal today.

The photos below show the fire this afternoon. The coal bed is much thicker than before, nearly 3" deep. The burning area of coal is not symetrical, the shape is the same a with the unmodified burn pot, I believe it is becaus of the way the auger pushes the coal up from the bottom, it is not even, but greater on one side of the retort.

I've cut back the auger feed rate to the lowest setting, 10-12# per hour, and yet I still have a much larger bed of burning coal. On average the bed of burning coal is about 14" in diameter.

Once I get a full 24 hours experience with the latest modified burnpot I'll report with more infomation.

Greg L..

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Here the larger coalbed is obvious, compare to some of the earlier posted photos.
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The flash washes out most of the flames, but this shows the asymetrical shape of the firebed. I don't think there is anything to be done about the uneven shape of the fire.
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LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: Charlie Z On: Mon Feb 12, 2007 8:51 am

Wow, that worked great!

Next, I'll bet you're thinking of an ash auger or something like that. I guess you've pulled your grate out to dump directly into the pan?

Did you get a price from Willburt on their residential stoker? It would be good to know what it might take to convert a hand-fired as a future project. :D

- Charlie
Charlie Z
 
Stove/Furnace Make: Coalbrookdale
Stove/Furnace Model: Darby

Visit Lehigh Anthracite