Firing with Coal and Ash Pan question

[barts]

I'd use heavy 1" angle iron, corner down, about 1/2" spacing. The open side facing upward will fill with ash, which will help the grate bars live longer. The cool air coming up from underneath will help, and the space between the bars won't get plugged.

- Bart

[Lopez Mike]

Hi, Bart! Where have you been hiding?

My grates lift out. Not a giant project to rebuild them if needed.

I don't think screen of most sorts would stand up long. The grates can get pretty hot. You might try some diamond mesh for an experiment.

The general design of grates is to have them maybe twice as deep as the gap between the bars. Heavier steel has more metal to erode before becoming a problem. I dunno if angle iron would stay cool enough even when full of ash. Worth a try for sure. Having the gaps get wider towards the bottom is normal practice but not as easy with bar stock.

I haven't done much coal firing but the full sized coal burning locomotives I've seen had sophisticated rocking grates to deal with hard clinker buildup. Some even have water circulating through them. Others on here will know much more about that.

Mike

[tempus fugit]

Hi, I have used angle iron for six seasons in Sarah Jane,the ash laying in the v keeps the bars cool. I burn a deep fire of Welsh steam coal with a 3/8" space between the bars. I also had the boards and the engine bearers scorch with the heat, so I fitted a false base to the boiler 1" deep and pump river water through via a spare crank driven pump,this cools the bottom of the boiler then fills my supply tank or goes overboard.

Graham

[barts]

Hi, Bart! Where have you been hiding?
Mike

I was in London after Thanksgiving for work... and managed to pick up a nice pair of mast head and stern lights to match my existing classic Italian brass port & starboard lights I got in the Netherlands in 1998. Need to have proper night lights even when running w/o the canopy.

I also had the boards and the engine bearers scorch with the heat, so I fitted a false base to the boiler 1" deep and pump river water through via a spare crank driven pump,this cools the bottom of the boiler then fills my supply tank or goes overboard.

I have a 1" false bottom in Otter's boiler as well, filled w/ Fiberfrax, stainless on top and then lightweight firebrick. This has worked pretty well over the last 16 years.... I'm considering adding the ability to burn wood for Otter; this would let me get rid of the propane bottle for starting....

- Bart

[DetroiTug]

I used to live in a rural area and we heated solely with wood in a heating stove for a number of years. It seemed to me after much usage, heating stoves worked best when the ashes were taken out regularly, at least daily. The boiler in the tug seems the same way. My theory is when ashes are allowed to accumulate, they are light and picked up by the draft air and interfere with the combustion. Of course we don't see this happening when the door is open. That is the first thing I do in the morning firing the tug, take out the ashes.

Another thing that wood stove manufacturers do or did to insulate the bottom and protect the floor was use sheet metal panels with air gaps in between to isolate the radiant heat.

-Ron

[fredrosse]

The inverted angle with ash for insulation in the "V" seems like a good solution, and will definately allow ordinary carbon steel bars to survive longer than would otherwise be expected. The inverted angle type bars would also be easier to keep clean, and would tend to clog much less often.

As far as enduring very high temperatures that are typical for the grates, stainless steel would be an almost ideal choice, stainless can endure red heat continuously, wheras ordinary steel can be "used up" in short order with an intense fire. I once fitted steel "turbulators" (twisted tapes) into a VFT boiler with an intense coal stoker fire, and these were destroyed in just a few days. Replaced them with stainless steel, and these held up for several years, as far as I know they are still in service. Type 316 stainless can take somewhat higher temperature than type 304, but either one is far far better than ordinary carbon steel.

[Lopez Mike]

Given Fred's advice on stainless steel, I would look around for some diamond mesh stainless as an interim solution. Just cut a a couple of squares that can be put in through the firebox door if there is no other easy access.

Fred,
I have VFT with 1" flues. Do you think it's worth doing to fit some tubulators? I notice that my RV propane fridge has one. It has a long twist. Is that just to keep it from flopping around? And do you think they should go the full length of the flues or only the bottom parts?

I haven't had much soot buildup in the flues since I quit throwing hunks of creosote pile ends in there (duh!). Sure did take off though.

Mike

[87gn@tahoe]

Mike, my father fitted the oil-fired Semple VFT 40 in his small boat with tubulators and he saw quite a significant increase in steam output... from not being able sustain over 1/2 throttle, to full throttle with safety blowing.

[Lopez Mike]

I think I'm headed for a sheet metal shop and have a bunch sheered off.

Were they full length? Or nearly so?

Mike

[87gn@tahoe]

Full length, mild steel (16 or 18ga maybe?), I think one full twist.

I would suggest stainless, as the tips had begun to erode after 15 years of steaming.