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.
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.