lsayre wrote:Is the entire coal bed really burning simultaneously, or is it only the volatiles that are burning at the very top of the coal bed (regardless of the depth of the bed)? If so, when you shake down, wouldn't it be all ashes going out, and no unburned coal remaining after each shake down?
Why stop there? Why not burn right into the hopper?
Yes, the kitchen range's coal bed is all glowing coals right down to the grates. There is a thin layer of ash that I leave on the grates during the day, but that ash layer has many gaps that the primary air coming in keeps open. The ash drawer area under the grates is still lit up from burning coal until it's time to shake and top off with fresh coal.
Because the range firebox doesn't hold as much coal, depth-wise, it gets shaken and topped off several times during the day. Starting with, when I wake up in the morning, then about a 30-45 minutes before cooking meals to raise the top plate temps up to cooking temps from just heating temps (a difference of about 100 degrees).
If we're doing a long baking session, such as a large chicken, turkey, or ham, it gets a quick shake and light top-off about midway through the baking to keep oven temps up.
At bed time, it gets a very thorough shake down and filled full with successive layers until it's filled right up to the top with burning coal. Once all the coal is burning (still has lots of blue ladies, but with built-in secondary air leaks around the removable top plates there's never any danger of puff backs). Then the primary is closed to a sliver, the oven and water tank dampers are put in in-direct mode, the MPD closed fully, and it's damped down for the over-night.
No hoppers to worry about burning through on my kitchen range, or my Glenwood 118 Oak.