Surdiac Hopper Fed Coal Stove

search Internet, there are very few central hopper fed coal stove, why?
It shall be much cheaper than auctomatic stoker.
Shake 2 or three times a day is not a problem.
Why American prefer complex than simple

Rube Goldberg School

madeinchina wrote:search Internet, there are very few central hopper fed coal stove, why?
It shall be much cheaper than auctomatic stoker.
Shake 2 or three times a day is not a problem.
Why American prefer complex than simple

A hopper fed stove is a step up from a typical hand fed stove. Fresh coal is pre-heated to ignite quicker. It is more convenient to load and there will be some automaic feeding between shakes. Another step up is a thermostatically controled damper to regulate heat.

Even though a coal fire can be starved for air to keep it burning for an extended period it does so at the cost of not burning all the volitiles plus generating carbon monoxide which is wastefull and should be burned to carbon dioxide. Efficiency suffers. There is only one setting that a stove will burn in its most efficient manner. Any departure from that setting either for more or less heat lessens efficiency.

A stoker stove on the other hand uses a small fire pot and simply feeds it faster or slower depending on heat output desired. It always burns hot thanks to the small chamber and can burn efficiently over a much wider range of heat output. You could duplicate this, to a degree, if you converted the fire chamber in a typical stove to a very small size and tended it every hour or so. Always burning hot.This would not be very practical.

A stoker also disposes of ash in a very neat manner by allowing the fresh coal to push the ash off the edge of the firebox to drop into the ashpan. Shakers in typical stoves are awkward and not nearly as effective.

As you point out this convenience and higher efficiency comes at the cost of simplicity and price to buy.

Richard

franco b wrote:

madeinchina wrote:search Internet, there are very few central hopper fed coal stove, why?
It shall be much cheaper than auctomatic stoker.
Shake 2 or three times a day is not a problem.
Why American prefer complex than simple

A hopper fed stove is a step up from a typical hand fed stove. Fresh coal is pre-heated to ignite quicker. It is more convenient to load and there will be some automaic feeding between shakes. Another step up is a thermostatically controled damper to regulate heat.

Even though a coal fire can be starved for air to keep it burning for an extended period it does so at the cost of not burning all the volitiles plus generating carbon monoxide which is wastefull and should be burned to carbon dioxide. Efficiency suffers. There is only one setting that a stove will burn in its most efficient manner. Any departure from that setting either for more or less heat lessens efficiency.

A stoker stove on the other hand uses a small fire pot and simply feeds it faster or slower depending on heat output desired. It always burns hot thanks to the small chamber and can burn efficiently over a much wider range of heat output. You could duplicate this, to a degree, if you converted the fire chamber in a typical stove to a very small size and tended it every hour or so. Always burning hot.This would not be very practical.

A stoker also disposes of ash in a very neat manner by allowing the fresh coal to push the ash off the edge of the firebox to drop into the ashpan. Shakers in typical stoves are awkward and not nearly as effective.

As you point out this convenience and higher efficiency comes at the cost of simplicity and price to buy.

Richard[/quote

Thanks a lot. I think I am clear now.
Stoker stove can always work under most favorable condition, highest efficiency.
But a hopper fed stove can have a second burning. When fresh air is less, fire is small, then more soot and co,
before entering flue, a second burning can takes use of WASTED soot and co.
Modern electronics is so clever, just measuring temperature, flow speed, soot/co content, second burning can be controlled by most favorable air supply, then highest efficiency overal.
Sensors/chips or air valve must be cheaper and reliable than auger.

Anyone can supply me a drawing of gravity fed stove. I am sure that I can add sensors/chips/valves, to guarantee highest efficiency at any temperature setting.

madeinchina wrote: Why American prefer complex than simple

The stoker mechanisms are not that complex, it's more a matter of convenience. For example we run our boiler year round because it also supplies hot water in the summer. With the stoker mechanism it can burn as little as 10lbs. of coal a day and it only needs to be filled with coal and the ashes removed once a week and truthfully it could probably go 2 weeks. With the proper setup you could have one that could run continuously with little work. They are expected to last 40 or 50 years with proper maintenance so the original cost although higher than a hand fed stove is long term investment that pays off in the end....

30 years old, expected lifespan is about 50 when it can be refurbished with a little work.

Total cost in replacement parts other than motors in that time: $0

hey thanks, even I didn't know all that! I thought stoker stoves were only for the convenience, never gave much thought to efficiencies...

to:Richard S.
1.Stoker needs electricity.
2.Motor and auger need care or replacement
3.Certain size of coal is needed, more expensive.
4.New hopper fed stove can work with or without electricity, can burning mixed sizes of coal, cheaper cost.

especially if they have those moon-beam powered lays potatoe chips for optimum burn rate and air valves. hamster,cage,mini generator, spare hamster...

we just use child labor for our non electric hopper stove, at the age of 13 they learn how to operate clean etc so finally my dh and I could go out for an evening and know they wouldn't suffocate themselves or freeze to death (can you see the tongue in my cheek?)

Ok. Its late summer here in Saugerties, the heart of the Hudson Valley, NY., and its time to wonder, "Should I convert this Old Surdiac Stove to wood, or waste more money on coal?" Of all the posts that I've seen on
this forum, the only one I can now consider to correct the horrible burn time and clinker problem is the "quality issue" of my pea-coal supplier. I have the book on the surdiac and it states that at approximately 3500 degrees the clinkers will form.(huh?, man that's hot!) Shaking down instructions, hopper tips, draft tips; nothing has made this thing burn more than 4 hours, not even constant manual intervention. CLINKERS, CLINKERS, AND MORE CLINKERS. They fill the bed and are hard as rock, and do not break apart to shake down. Is this then the end of my foray into a lasting, conforting warmth for winter? I want this thing to work because I love the warmth it provides......PROFESSIONALS, EXPERIENCED USERS, SUFFERERs of the cold of winter like me, please respond. (OR MAKE ME AN OFFER ON THIS STOVE, which is complete and whole and undamaged by age. Brrrrrrrr. A cold wind is blowing my way. The only thing I hate more than the cold winds of the dark season, is the chill of failure caused by GIVING UP!

I would certainly try another coal supplier. You should be able to find Blashak coal which is decent.

Richard

try to get a bag of better quality anthracite and see how that goes...clinkers is a term initially used for bituminous, and they do form with the impurities in coal (silicas whatnot).

other thoughts: cleaning out the compartments behind the stove? that fine coal ash gets everywhere! even in the back corners of the grates and under the ash pan we have to clean out when we shake down (poke down is more like it for our stove).

finally, a big thank you to Woodsmans stove parts...I remeasured the grates we had, ordered what I think would fit, and they did, so now just the glass to replace and we'll hopefully be good to go for another season of warmth...

we did buy a new woodstove, up to 74K BTUs and hopefully 10 hours-to-coals burn time, so that should be good backup to our coal stove which can be a little underpowered when the temps go to freezing and the wind starts blowing. We've been able to get some free wood from downed trees in all the storms we had this summer, so with the 3 cords we have left over from last year to burn this year, and the six cords we'll season this winter for next year, we should be in good shape after the electric rates fly up beyond the heavens

bgbraker wrote:Shaking down instructions, hopper tips, draft tips; nothing has made this thing burn more than 4 hours, not even constant manual intervention. CLINKERS, CLINKERS, AND MORE CLINKERS. They fill the bed and are hard as rock, and do not break apart to shake down.

I got my Surdiac about a year ago and it took a while to figure out how to get it working right. My guess is that you are giving it too much air. That gives a hot fire, which grows clinkers, but the stove doesn't get as hot as you would expect because much of the heat goes up the stack. As it started to warm outside last spring I closed off the air to reduce the heat and found that I had to close it quite a bit to have any affect. When I did get the temp down the clinkers stopped forming and the burn time went from 7 or 8 hours to 12 to 14 with a reduction in the amount of coal used.

The other thing I found was it is best to fill the hopper right to the top. Early on I had the problem of clinkers preventing the burnt coal from crumbling down to make room for fresh coal from the hopper. I mistook the problem as being that the coal was too tightly packed in the hopper to flow out. So I wasn't filling the hopper to the top in an attempt to avoid that. With the clinker problem under control I found that it works better to fill it to the top.

Some coal is better than others about not forming clinkers. If you have multiple sources you might want to experiment with a few bags from each.

Bruce

Just one other thought , did you ever put a draft gauge on the unit to make sure the draft is in the proper range.Excessive draft would tend to accelerate the air flow thru even a baffled down primary intake. Don't quit on the Surdiac just yet.

an update on our old surdiac...dh says with the new gasketing and the new grates that we are getting longer burn times, might also be the red ash coal we've been using too, and I don't notice the coal smell as strongly outside either, all good things.