Conversion of a Hand Feed Boiler to a Stoker Boiler

I've been working on this project for a few months. Thanks to a link from a friend, I was able to buy this Iron Fireman coal stoker. [Thanks Matt!] It was in the Upper Peninsula of Michigan!

I got it home, cleaned out about a grocery-bag full of mouse nests from the combustion air tubes and air chamber around the firepot [also called a retort]. There is an air tube with a removable cap that is also a clean-out tube. I thought I had cleaned out all the mouse nests, and had some air blowing into the firepot, so I just had to give it a trial burn.

The fire was not spectacular, I opened the cleanout tube and while there was air coming out, it wasn't very enthusiastic. I went to the other side of the stoker unit and was messing with some of the air controls on the combustion blower feed tube. I loosened a lock bolt on one lever and gave it a trial flip back and forth, and suddenly it was snowing!! Snowing white fluff of yet another mouse nest, mouse food [corn] and 30 years of dust!! What a mess, but I had a heck of a lot more air. The mouse nest had been held in place by the butterfly air flap in the air tube.

Now the fire was burning very well.

The literature on this stoker, old literature from the '30's and 40's says it is for Bitumonous coal. So I tried to burn Bitumonous in it. It has been a frustrating failure on Bituminous coal. Bituminous gets soft and sticky as it is heated, the chunks of coal tend to stick together in a lump. The coal pieces in the firepot would stick together as they burned, creating a big chunk of stuck-together ash, sort of like a fragile clinker that was pushed up out of the retort [firepot] by the incoming fresh coal from below. Once the chunk of burning ash got too tall and top heavy, it fell off the top of the fresh coal and took the burning coal with it, so the fire went out.

In several trials I had a cold boiler and the ashpan full of unburnt coal after a few hours. So in my experience with my Bituminous coal, it was a failure.

So I bought some Rice size Anthracite coal, what a difference. The coal burns in a nice consistant manner, looks like a big thick glowing red pancake on top of the retort.

In my initial anthracite-burning trial in my boiler I ran the stoker on it's lowest setting, this stoker has the combustion fan run right off the shaft of the 1/4 HP. motor and a three-step belt/pulley setup to run the stoker's gearbox for the coal feed auger. The three speeds for the auger are ~ 10#, 20# and 30# of coal per hour. With the belts set at the lowest setting I did actually burn about 10# of rice coal an hour, On an overnight burn I pumped 120# of coal through the retort. But the coal was only half burning, the ash was about half black coal, and a lot of partially burnt coal.

So I installed an additional air blower into the clean-out air tube, and it runs continously, I added a timer for the stoker motor. When the aquastat calls for heat, the timer runs the stoker motor and auger for 15 minutes then off for 15 minutes. The second fan feeds air to the fire while the stoker is shut down. This burns the coal in the retort completly and I have nothing but ash in the ash pan, It looks like large Grape-Nuts breakfast cereal or granola. I'm burning half the coal as before, and I'm maintaining water temp of 150* with 5-10* outside temperature [no wind]. I'm hoping the stoker will be able to keep up with -10* and a wind, but this may be optimistic.

Below are photos as well as a pdf file of a 1930's sales brochure for the stoker .

So far I'm really happy with the function, heat and coal comsumption burning rice anthracite. I wish I could get some buckwheat to try in it, to see if I get more or less heat from the slightly bigger coal.

Sorry for the long-winded post, I hope you found it interesting.

Greg L

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Here are a couple more photos of the Stoker and boiler.

Nice Work Greg!

Looks great! An oldie but a goodie!

LsFarm wrote: The coal pieces in the firepot would stick together as they burned, creating a big chunk of stuck-together ash, sort of like a fragile clinker that was pushed up out of the retort [firepot] by the incoming fresh coal from below. Once the chunk of burning ash got too tall and top heavy, it fell off the top of the fresh coal and took the burning coal with it, so the fire went out.

Greg L

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Very interesting. Your stoker is almost identical to the Willburt stoker here:
**Broken Link(s) Removed** It also says "NOT FOR ANTHRACITE". SO, I wonder what is the key to burning bituminous? I see in your Iron Fireman literature they advertise clinker tongs and such. I wonder if the idea is to go in regularly and bust up the clinker and pull it out of the fire before it topples over? Do you think it would make it overnight without attention? Also, if you had some dead plates around the retort, the clinker couldn't fall over so far and take the fire with it.

I'm jealous. I have stoker envy.

Chris

Hi Chris. I called the Will-Burt company, and spoke with a rep. He supplied me with the pdf file on the stoker. Will-Burt bought or originated from the Iron Fireman company. I'm not sure of the history, but Will-Burt has the archives and a very few parts for the old stokers.

I'm going to add plates around the retort to add surface area for more heat output, but I don't think they would keep the tall column of ash from taking the fire with it.

I asked the rep at Will-Burt about burning anthracite vs bituminous. He said it would burn anthracite just fine, but cleaning out the ash would be a mess. With bituminous the ash would be in chunks and clumps [clinkers] and would be much easier to clean out of the firebox. !!

I asked him about having the retort above an ashpan and have the ash fall off the edge and into the ashpan. He said he had never seen it set up that way but should work. He said that their units are often cast into place with refractory cement and the ash collects around the retort. Sounds like a real mess, requiring daily cleaning. I'll take the ashpan approach and slide it out for cleaning every day or so.

The EFM and VanWert stokers are set up like mine, an ash pan below the retort. What is the origine of the term retort??

If the retort was in a firebox wth close, near vertical sides it may hold the ash in position long enough to burn it up without it falling over and loosing the fire. I'm waiting to see the firebox/retort layout of the Combustioneer stoker that a forum member has.

Take care, Greg

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Here is a photo explaining why I made a tricycle gear for the stoker instead of 4 wheeled, One is that the floor is not all that level, and three wheels will always be stable, and the other is that I needed to have room to get the long ashpan out of the boiler.

The length of the ash pan shows how long the firebox is in this boiler. I REALLY needed a firebox reducer!

Also a photo of one of the bituminous ash/clinkers growing up out of the firepot during an experimental burn.

Greg L.

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LsFarm wrote:
Also a photo of one of the bituminous ash/clinkers growing up out of the firepot during an experimental burn.

Greg L.

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That's cool. Looks like one of those 'growing crystal' things I did as a kid.

How long did it take for the clinker to form like that? It might be just a matter of going in there and busting it up a few times a day.

Chris

The stoker feed was on the 10# per hour feed rate, so it took less than an hour to grow what you see.

Greg L

Amazing. So, how the heck did anyone burn bituminous in those stokers without having to run to the basement every few hours to bust up a clinker?

Chris

That is totally amazing. I have never seen a stoker before. I assume that most stokers are like this? The ash is just pushed out of the burning area onto the floor of the boiler box? How do you start a fire in something like that?

Hi Nuke, actually this is more of a boiler or big furnace type of stoker. Go to http://www.efmheating.com . You can see the type of application for this underfeed stoker.

Most stoker stoves use a flat bed with holes in the bed, air blowing up through the holes into the burning coal above. The bed is kept covered by various methods either pusher blocks, shovels, wipers etc, but somehow the bed is kept covered with a layer of coal. The quantity on the bed burning determines the amount of heat. Some stokers have a bed about 8" wide, and when in 'idle' mode will only have an inch or so of flame up near the very start of the bed. When the stove is calling for full heat, then the entire 8" x10" bed is covered in red coals with blue flames dancing above, pretty neat to watch.

If you wan't I'll post some carpet-bed type stoker photos later.

Greg L

LsFarm wrote: If you wan't I'll post some carpet-bed type stoker photos later.

Greg L

Yes please! Pics pics and more pics!

Chris

nuke wrote: How do you start a fire in something like that?

You start a fire.... There is air blowing up from the bottom so it's quite easy. You can have a fire the size of the "upside down bell" as I refer to it in about 10-15 minutes. You start with some wood, get a decent wood fire going without turning it on. Once you have a resonable wood fire going put some coal on and turn it on.

nuke wrote:How do you start a fire in something like that?

I can start a fire in any design in two minutes, using my oxygen - acetylene torch. Sorry couldn't resist. I've started fires in things I didn't want to too!

Yanche

Yanche, carefull with those unwanted fires!!

I haven't had great luck with the hardwood/kindling fire to start the stoker. I gave up and followed some advice from the forum. I bought several emegency road-flares. Cut them into 1/4's, each about 2" long, lite it with a BBQ lighter, let it get really going, and droped in the burn pot, and covered it with a double hand-full of coal, with the air coming up from the bottom, it was a nice fire in about 15 minutes. The flares have magnesium in them, so they burn very hot.

I use Yanche's method when I light one of my LeisureLine stokers in the shop, the oxy-acetylene torch does a remarkable job lighting the coal. But my torch tank rack doesn't have ATV tires or a good off-road suspension so dragging the tanks 150' to the boiler-building is out of the question.

Chris, I don't know if bituminous with a lower swelling index would keep the tall piers of ash from forming or not. It may just be my coal. But I have faith in the anthracite coal, it will burn till it is gone, The bituminous has let me down too often.

What is strange is that when I start a hand load fire, I build a hot wood fire, the add Bituminous because it lights on fire so much easier than anthracite!! So why does the stuff not burn well in the stoker's retort?? I can't figure it out. But after waking up cold a couple of nights and having to pull out the stoker, clean out the unburnt coal, reinstall the grate, start a wood fire and get a coal fire going, I'm not going to trust it anymore.

Greg L

I'll start antother thread with photos of various stoker designs I have. This way it will be a good reference for members who want to see them.

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