Drilling the Grate

Drilling the Grate

PostBy: tsb On: Thu Dec 05, 2013 8:38 pm

I've been on the quest of reducing the amount of unburned coal
on a flat bed stoker grate. I've tried a larger fan, a deeper bed
and finally drilling more holes in the grate.
Grate Drilling.jpg
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It seems to make for a more lively flame and a lighter
ash, but I don't think it has improved the amount of
unburned in the ash pan.
The quest goes on.
tsb
 
Stoker Coal Boiler: Binford 2000
Hot Air Coal Stoker Stove: LL Pioneer top vent
Hand Fed Coal Stove: Saey Hanover II

Re: Drilling the Grate

PostBy: Rigar On: Thu Dec 05, 2013 9:45 pm

...lighter ash and better flame sounds like its helping...if nothing else maybe the coal you DO burn is burning more completely...?
Rigar
 
Hot Air Coal Stoker Furnace: Keystoker A 150
Coal Size/Type: anthracite rice
Stove/Furnace Make: Keystoker
Stove/Furnace Model: A 150 warm air furnace

Re: Drilling the Grate

PostBy: 2001Sierra On: Thu Dec 05, 2013 11:46 pm

What is your definition of unburnt coal with all do respect? I too was surprised when I went from a hand fed to a stoker how the ash changed, but frankly I am now heating more with less :roll: Who would of thunk :oops:
2001Sierra
 
Hot Air Coal Stoker Stove: Keystoker 90 Chimney vent
Coal Size/Type: Rice
Other Heating: Buderus Oil Boiler 3115-34
Stove/Furnace Model: Keystoker 90 Chimney Vent

Visit Lehigh Anthracite

Re: Drilling the Grate

PostBy: tsb On: Fri Dec 06, 2013 12:02 am

Rice coal ash that is dumped and rained on shows a percentage of
unburned something. It may be coal,it may be shale, but it is something.
I just like to tinker and see if I can get the most amount of heat and the
least amount of unburned.
My latest thought was that a piece of coal that starts on it's journey down the grate
would travel in about a straight line. That means that about 1/3 of the coal never gets
directly over an air hole. By drilling the new pattern, I thought that it would increase
the chance of all the coal getting more air in that area.
I get plenty of heat out of the boiler, I'm just playing mostly.
tsb
 
Stoker Coal Boiler: Binford 2000
Hot Air Coal Stoker Stove: LL Pioneer top vent
Hand Fed Coal Stove: Saey Hanover II

Re: Drilling the Grate

PostBy: whistlenut On: Fri Dec 06, 2013 12:03 am

There is no doubt that you have increased to potential BTU gain. More air...available fuel......IT HAS TO SMARTEN UP THE FIRE! It is like trying to get more HP out of an engine.....bigger valves, plenty of fuel, and now the blower IS acting like a supercharger. It may make the ability to choke it down more tricky, but I'll bet you have a handle on that, also. :idea: :!: :blowup:
whistlenut
 
Stoker Coal Boiler: AA130's,260's, AHS130&260's,EFM900,GJ&VanWert
Hand Fed Coal Boiler: Franks Boiler,Itasca415,NYer130,Van Wert
Hot Air Coal Stoker Furnace: Yellow Flame
Hot Air Coal Stoker Stove: Alaska-4,Keystoker-2,
Hand Fed Coal Stove: Alaska,Gibraltor,Keystone,Vc Vigilant 2
Hand Fed Coal Furnace: Van Wert, NYer's, Ford,Jensen.
Coal Size/Type: Rice,Buck,Pea,Nut&Stove
Other Heating: Oil HWBB

Re: Drilling the Grate

PostBy: captcaper On: Fri Dec 06, 2013 5:47 am

Why doesn't turning down the feed rate do it? I get the same thing in my coal. My Coal dealer who has a stoker said that that is spent and if you tried to burn it again it wouldn't burn. I'm not about to try. But I bet it's shale.
captcaper
 
Stove/Furnace Make: Harman Super Magnum
Stove/Furnace Model: Super Magnum Stoker

Re: Drilling the Grate

PostBy: WNYRob On: Fri Dec 06, 2013 9:14 am

Another way to think about it is, as the air is being blown through the coal bed, it isn't traveling directly up in a straight line. As soon as it leaves the grate and hits the bottom of the coal bed it gets deflected in a number of different directions (albeit, minutely), so the coal pieces surrounding the air holes are still getting hit by air.

Obviously, by the flame's appearance the general direction of the air flow is up, but there is probably a bunch of little "vertices" created within the coal bed before the air leaves the top.
WNYRob
 
Hot Air Coal Stoker Stove: Keystoker Koker controlled with CoalTrol

Re: Drilling the Grate

PostBy: dave brode On: Sat Dec 07, 2013 3:12 pm

tsb,

I'm glad that I'm not the only one that suffers this ailment. LOL. I often pick what look like pieces of partially burned coal out of the bucket and see if they will break or not. If they will not, I frown, just 'knowing" that they could have somehow been forced to give me another btu.

Yiour bed looks very juch like that of a KAA-2's. Fyi, the grates on mine [bought new] have a couple/three rows of holes at the end that were hand drilled [not too straight]. So, I trust that at some point, Keystoker felt that adding the holes was best.

There are many threads here on the subject. I have reluctantly come to the point that I agree that more than the idea amount of air might make the ash look better, but it is wasting heat by blowing it up the flue. However, I had not thought about what you are doing about here. You could be dispersing the same amount of air in a better pattern.

On a related subject, I have read opinion here that one will always see some unburned coal when using a flat bed. I am still planning to tilt my bed down at 5* or so. It seems to me that if the coal was less densely packed, the coal might "see" more air, with the same air amount. The coal might move in bigger jumps with the bed tilted down, which *might* allow it to be less dense. Here's a thread on that, in case you haven't seen it; flat bed [KAA2] vs sloped bed stokers

fwiw, I may try to fashion a 3 sided "adapter" with wedge shaped sides just to try it. If in case it did work [or I thought that it did LOL], the mounting flange could be cut off and re-welded for a permanent down angle..

Dave
Last edited by dave brode on Sat Dec 07, 2013 3:28 pm, edited 1 time in total.
dave brode
 
Stoker Coal Boiler: Keystoker KAA-2
Hand Fed Coal Boiler: used to have a 5 section Red Square
Coal Size/Type: rice anthracite

Re: Drilling the Grate

PostBy: dave brode On: Sat Dec 07, 2013 3:26 pm

p.s. - here's another subject that you can ponder: the "throat adjustment' on the bigger KS'. Keystoker Ka-6 operation guide.

Evidently, they can adjust theirs up/down to change the depth of the coal on the bed. Looking at the fire, it seems that if it was not quite as deep, it might just burn better.

I must admit that I made a 1/2" spacer that I tried. I put it in place of the little tin piece. My mistake was, it was too long, and extended back into the opening under the hopper about 5/8". I think that some of the stroke was being wated, shoving coal up into that dead space, then having it fall back down. So, even at full stroke, there wasn't enough coal being fed. I have a piece of 3/8" that I'm going to try. :roll:

If I didn't waste all of the heat that I do while staring through the open door, I could save coal! LOL

Dave
dave brode
 
Stoker Coal Boiler: Keystoker KAA-2
Hand Fed Coal Boiler: used to have a 5 section Red Square
Coal Size/Type: rice anthracite

Visit Lehigh Anthracite