What does a stoker mechanism look like?

LsFarm · By: **LsFarm** On: Wed Jan 31, 2007 9:29 pm

Since there is interest I'll post photos of what I can to illustrate some stoker mechanisms I've been playing with.

Please understand I am NOT in any way an expert, but I am a 'sponge' for knowledge, when I set out to learn about something I really go after it. I'm jsut sharing what I have learned. I hope other forum members will chime in with their own photos and help fill in the gaps.

I'll try to give a brief summary of the most common stoker types. There are some specialized stoker units that are in use in only one type of application, such as the AHS 130 and AAnderson type. I've not had a chance to put hands on one of these units. so I'll leave it to the forum members to post photos of their specific stoker designs.

The most common type of stoker in use is the bed or carpet type. These are in use with various variations and patented features in LeisureLine, Keystoker, Alaska, Harmon, Reading, Losch, and I'm sure many others I'm not familiar with. The bed or carpet bed is often or usually called the grate. I'm not sure where or from whom I heard the term carpet or bed.

The next type is a burner pot or under feed stoker. These are in use in EFM boilers, and were in VanWert boilers, EFM Furnaces, and again probably several other makes I'm not familiar with.

Then there is the add-on or conversion stoker, like the 'antique' Iron Fireman, Combustioneer. and still currently manufactured by Will-Burt Corporation.

Below is a photo of the stoker in a LeisureLine Pioneer model, 2004 vintage. You can clearly see the holes in the bed where the combustion air comes up through and feeds the layer of coal on the bed.

The next photo id of the pusher bar from under the hopper. I'm holding the adjusting mechanism. There is an arm on a slow turning gearbox that pushes the bar or shovel about every minute, this is adjustable on this stove with a reostat. There is a combustion blower that keeps air under the bed flowing up through the coal.

The third photo is of a LeisureLine Hyfire ! with both burners really cookin'. The large 90K btu burner on the right is the same as the previous photos, the small burner is a 40K unit. You can see the coal burning over most of the carpet bed and the flames rising above.

Greg

LsFarm · By: **LsFarm** On: Wed Jan 31, 2007 9:41 pm

Here is the Iron Fireman conversion stoker that I have in use in my boiler. I don't know if this particular design was ever in it's own boiler or furnace, In the late 40's and the 50's Iron Fireman marketed their own line of coal and oil boilers and furnaces.

The hopper holds several hundred pounds of coal, the auger in the bottom of the hopper pushes the coal to the bottom of the firepot or retort.

The combustion blower feeds air in a pipe parallel to the auger pipe, feeding air around the burn pot. There are rows of holes in the inside of the burnpot feeding air to the funnel of burning coal. The auger also has an air pipe feeding air right at the base of the pot where the auger pushes the coal up into the 'funnel' or retort.

The first photo is of the hopper and auger. The second is the retort with one of the 1/4 sections removed, showing the mouse nest in the air chamber. The third shows the motor, fan and gearbox with the three-speed belt drive.

Greg L

LsFarm · By: **LsFarm** On: Wed Jan 31, 2007 9:47 pm

More Iron Fireman photos

LsFarm · By: **LsFarm** On: Wed Jan 31, 2007 9:55 pm

Here is the 'Cadilac' of under feed stokers. This is an EFM unit. It is desigined for anthracite. There are more air holes to feed the fire and the mechanism is adjustable to feed coal at ten different rates from 2.5 to 25# of coal per hour.

These units are still in production in EFM boilers.

LsFarm · By: **LsFarm** On: Wed Jan 31, 2007 10:01 pm

More EFM stoker photos

LsFarm · By: **LsFarm** On: Wed Jan 31, 2007 10:04 pm

We have a forum member 'Motor Stoker' who has a unique stoker unit, I hope he will read this and post some photos of the unit here.

There are at least three AHS 130 owners, maybe one can scan and post the line drawing and or schematic with a photo or two of the interesting AHS reverse flow system.

We have a member with a Combustioneer unit who will have some photos soon as well.

Yanche · By: **Yanche** On: Thu Feb 01, 2007 12:32 am

The attached drawing shows a cut away view of the Eshland (now Alternate Heating Systems) or Axeman-Andersen anthracite only stoker boilers. There are several design features that are unique to this boiler. It is a gravity fed boiler. Pea sized anthracite coal slides down the "coal inlet tube" slowly. The rate is controlled by the burn rate. The combustion "fan" is inside the boiler in the hot burning coal gases. In the actual boiler the illustrated "fan" would be where the point of the straight brown arrow is. This "fan" sucks combustion air up through the coal bed. When the hot gases exit the fan blades it makes a 180 degree turn. Next the gases move on to the cyclone ash separator. There it's swirled around and most of the fly ash falls down to the grate. The flue gases exit the boiler at the top of the cyclone. The entire flue gas path is surrounded by boiler water.

The ash grate is a heavy solid steel plate that is supported on four "roller bearings". There is a motor drive link that slowly moves the ash plate. When it is moving to the left in the illustration it cuts off part of the ash in the very bottom of the fire pile. When the same grate is moving to the right the previous cut off ash falls into the "ash tub".

The "ceramic heat shield" is what the hot flue gases impinge upon as they make the 180 degree turn. It's needed because at this point the gases are very, very hot. The turbulence and the flinging of the ash against the boiler tubes makes for good heat transfer. The burning coal is only about 6 inches in diameter and rests on a bed of ash. What's not shown in the illustration is a small oval observation port in the front (right hidden side in illustration). This is above the burning coal. When the blower "fan" is turning a flapper value on this port is closed. When the "fan" is off the flapper valve is open allowing a natural draft above the burning coal. When the "fan" is off the boiler fire is idling.

In the illustration the slanting pipe is the unique A-A hollow auger coal feed. The AHS version of the boiler replaces this with a large capacity funnel perched on top of the coal inlet tube. It holds 300+ pounds of coal.

Yanche

HardWood · By: **HardWood** On: Thu Feb 01, 2007 8:12 am

Here are some pics of my Combustioneer Mark IV

HardWood · By: **HardWood** On: Thu Feb 01, 2007 8:14 am

More pics

europachris · By: **europachris** On: Thu Feb 01, 2007 8:57 am

Nice pics, Harry! Do you have any of the inside of the firebox?

Does the stove have it's own blower or is it plumbed in series with the gas furnace?

Chris

HardWood · By: **HardWood** On: Thu Feb 01, 2007 12:43 pm

Here is one I took with the fire going but the blower is off.

I hooked the coal stove parallel to the gas furnace. There are two barometric dampers. One is above the Combustioneer and the other is before the cold air return.

HardWood · By: **HardWood** On: Thu Feb 01, 2007 12:48 pm

Forgot to answer one of your questions.

The stove has its own fan, but it is not sufficient as a whole house unit. I will be adding a squirrel cage soon.

Even so, this stove keeps the house warm.

europachris · By: **europachris** On: Thu Feb 01, 2007 12:53 pm

Nice! Do you have problems with the ash fusing together into a huge lump? Another member here, Greg (LsFarm) had a problem burning bituminous in his Iron Fireman as the ash would fuse, grow out of the fire pot, and fall over, taking the fire with it. The Combustioneer is a similar, underfeed stoker, I believe, so it 'should' suffer the same problems.

I assume you're burning Ohio bituminous?

Chris

HardWood · By: **HardWood** On: Thu Feb 01, 2007 1:03 pm

When that happened I adjusted the blower baffle to allow a little more air. The blower air sems to be a fine tuning issue with this furnace. Too much and the fire will "blow" out. Too little and the coal will melt into a column above the pot.

I think I now have it adjusted correctly. 6 turns out, about 3/16" gap between the baffle and the blower. I had it 12 turns out and the fire went out. I had it 4 turns out and would get the "tower" aboce the pot.

Yep, I am burning Bituminous

europachris · By: **europachris** On: Thu Feb 01, 2007 1:09 pm

Thanks! That is interesting how LESS air caused the ash to tower above the pot. I would have thought MORE air would burn the fire hotter and cause the ash to melt.

OK, *LAST* question - how much smoke to you get out of the chimney when you're burning well? When we tried bituminous in our hand-fed furnace years ago, it appeared that we had a tire fire going at our house (or we were trying to pretend the house was really a steam engine). It was definitely NOT a pretty sight.

Chris

What does a stoker mechanism look like?

What does a stoker mechanism look like?

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