Coalgun- Puff backs & Explosions

Re: Coalgun- Puff backs & Explosions

PostBy: freetown fred On: Tue Dec 24, 2013 11:54 am

Back at ya my friend:)
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: Coalgun- Puff backs & Explosions

PostBy: McGiever On: Tue Dec 24, 2013 4:24 pm

greenftechn wrote:
it seems that rather than add on a bolt on electrical kludge, the straight forward solution would be to retro the newer models back to the way the older models (the ones with fewer problems) work.


Except the chain drive did create maintenance issues. Reliability also, if the chain was not maintained. The newer setup is simpler and less costly to manufacture, even with the mode switch added in. The early direct drive systems' grate speed was higher than optimum, and much higher than with the chain drive. Now the grate speed can be electronically controlled with great flexibility.


Looks like the problem was both created by and solved by "The Bean Counter"

Whatever happened to the good ole days when some Old Smart Engineers used to make all the design change decisions???
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Hot Air Coal Stoker Stove: HARMAN MAGNUM
Hand Fed Coal Stove: RADIANT HOME AIR BLAST
Baseburners & Antiques: OUR GLENWOOD 111 BASEBURNER "1908"
Coal Size/Type: PEA / ANTHRACITE, NUT-STOVE / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Coalgun- Puff backs & Explosions

PostBy: Yanche On: Wed Dec 25, 2013 11:48 pm

greenftechn wrote:
it seems that rather than add on a bolt on electrical kludge, the straight forward solution would be to retro the newer models back to the way the older models (the ones with fewer problems) work.


Except the chain drive did create maintenance issues. Reliability also, if the chain was not maintained. The newer setup is simpler and less costly to manufacture, even with the mode switch added in. The early direct drive systems' grate speed was higher than optimum, and much higher than with the chain drive. Now the grate speed can be electronically controlled with great flexibility.


I've read over the last couple of pages describing the new mode switch option and understand it's great adjustment flexibility. What's missing is the desired grate speed, or range of speeds for optimum operation. So my question goes to AHS ... what is the speed, rate of grate travel (inches/per minute) for satisfactory operation? How did you determine the necessary speed range? Once we know the desired speed there are many possible implementations.

My AHS 130 uses the older percentage timer control and a fixed speed chain drive. This system is not a feedback control system, it's just open loop. Once the burning height is properly established, by stopping or forcing ashing, the percentage timer controls the boiler just fine. I haven' had a "puff back" in years.

I've been critical of the thermo-ash control feedback control system. It seems to me the "new" mode switch design is just a new implementation of the older percentage timer open loop control system. I fail to understand how making a temperature measurement, especially with a thermocouple, under the grate is sufficiently correlated to fire height in the antratube or combustion parameters that would cause a puff back. For any closed loop control system to work, the measured parameter, temperature in this case, has to be related to what you are trying to control. It's just not in this case. Wrong feedback sensor in the wrong position.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: Coalgun- Puff backs & Explosions

PostBy: Kennebago On: Thu Dec 26, 2013 2:10 pm

Well, I have finally completely read through the 53 pages of posts. I have read with interest many of the comments, a number of them right on the money........ I have designed furnace systems in my past career and also interfaced with a lot of complex systems far beyond manual control capabilities. What I see here is an older technology, updated to make it more efficient. But along the way It seems to me some of the selling features have been muddled a bit. It's automatic, but you have to top the hopper on a regular basis, it's efficient but you want to send the volatiles up the flue rather than burning them where they can contribute to the efficiency - etc, etc.

As someone mentioned earlier, to control a variable you want to measure it directly and the good news is in this day and age you can directly measure almost anything and with modern PLC controllers you can control it in a closed loop fashion. This does NOT have to mean a lot more cost - it just means taking an approach that is commensurate with the problem at hand. Many problems that were not solvable in the 40's (Compare that carburated DeSoto with a 2014 FI Chevy)are easily solved today. Seems to me there is an opportunity for someone (perhaps AHS) to re-engineer a boiler system, to make it efficient, automatic, cost effective and above all safe.

Things like combustion mixtures can be measured and controlled, the need for air can be anticipated and injected so its there when its needed. My guess is that one of the biggest problems is that the size of the market won't support the R&D necessary to put such a unit on the market -- Ohhh - if only I was a bit younger.

One other comment - nothing in what I just said that others here haven't said already. Just lamenting the fact that no-one seems to be doing the work necessary. I am a big Coal fan - but it could be even more impressive.

One last thing --- I am really impressed by the collective brain power and ingenuity of the folks on this forum. You guys are the best - here's wishing you a "boom-free" new year.
Stay warm.
Kennebago
 
Stoker Coal Boiler: Coming Spring 2014
Baseburners & Antiques: Glenwood Oak / Home Grand Restoration Projects
Other Heating: Arrgghh "Oil Boiler"

Re: Coalgun- Puff backs & Explosions

PostBy: Hambden Bob On: Thu Dec 26, 2013 3:35 pm

Welcome to Our Board,Mister ! We're glad to have both You and Your Mind in Cahoots with the rest of the "Mad Scientists" that bring some Amazing Brainpans to our Arsenal of Incendiary Knowledge ! This has been an amazing Post String for our Puff-Back Sufferers. It's become quite the Clearinghouse. I'm glad that AHS has fallen back into Ownership that cares and comes on here to try to rectify the issues. People have spent a damn good sum of money to aquire these units. I encourage all to stay with the effort to get things where they need to be. I know it's frustrating,but you guys may be starting to turn the corner due to the new Ownership. Tally-Ho ! :flex:
Hambden Bob
 
Hot Air Coal Stoker Stove: Harman 1998 Magnum Stoker
Coal Size/Type: Rice-A-Roni !

Re: Coalgun- Puff backs & Explosions

PostBy: titleist1 On: Thu Dec 26, 2013 4:28 pm

Kennebago wrote:One last thing --- I am really impressed by the collective brain power and ingenuity of the folks on this forum.


Ok, you've really screwed up now..... :(

You start using words like ingenuity and brain power in the same sentence as coal burning and the word may get out that we are on to something special with burning these black rocks. Pretty soon everyone will want to switch to coal and it will be in short supply! :mad:

It's better if our neighbors think we are a bit 'touched in the head' when they look through our windows during a cold snap in February and see us walking through the house in our underwear. It keeps them from coming over for a visit and discovering how warm we are. Just ask FreetownFred or Coalnewbie it has worked for them for years. :sick:

My neighbors think the chimney on one end of the house is for decoration since they never see any smoke coming out of it! My one neighbor is a wood burner and I thank him every once in a while for letting me know which way the wind is blowing when i go out to dump my ash pan. He still hasn't caught on. :lol:

Kennebago wrote:Ohhh - if only I was a bit younger
C'mon man, if you're less than 100 you're young enuff to jump in with both feet!
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: Kennebago On: Thu Dec 26, 2013 4:43 pm

I love the humor! You made my day --- and I am less than 100 so maybe I should take your advice and jump!!
I also have a friend that burns wood - spent a month stacking it in his basement - bought wood that was cut last winter to be sure it was dry -- had it de-barked so it wouldn't make a lot of dirt and bring bugs into the house - and oh - paid almost $300 a cord - and he thinks I AM CRAZY to want to burn coal --- you are right -- big secret!!
Kennebago
 
Stoker Coal Boiler: Coming Spring 2014
Baseburners & Antiques: Glenwood Oak / Home Grand Restoration Projects
Other Heating: Arrgghh "Oil Boiler"

Re: Coalgun- Puff backs & Explosions

PostBy: NWBuilder On: Thu Jan 02, 2014 8:08 pm

Ok this is a little different for me. I have had a few smaller sized puff backs in the past but today I actually had back to back puff backs while the blower was on. I have had several throughout the day which is also very unusual for me. I seldom get them. I don't know if it is because the temps are so low and the boiler is running so often but I am getting them now. It could be the draft is messed up as we have lots of wind today as well. Just thought I would put that out there. Ken
NWBuilder
 
Stoker Coal Boiler: Ahs 130
Coal Size/Type: Burning Pea anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Thu Jan 02, 2014 8:20 pm

NWBuilder wrote:Ok this is a little different for me. I have had a few smaller sized puff backs in the past but today I actually had back to back puff backs while the blower was on. I have had several throughout the day which is also very unusual for me. I seldom get them. I don't know if it is because the temps are so low and the boiler is running so often but I am getting them now. It could be the draft is messed up as we have lots of wind today as well. Just thought I would put that out there. Ken


The only time I ever experienced puffs with the blower on (in addition to when it cut off) was after I oiled my coal. And I had them back to back just as you have described. I'm not convinced that Coal Guns like oiled coal.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Stockton Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Coalgun- Puff backs & Explosions

PostBy: NWBuilder On: Thu Jan 02, 2014 8:27 pm

lsayre wrote:
NWBuilder wrote:Ok this is a little different for me. I have had a few smaller sized puff backs in the past but today I actually had back to back puff backs while the blower was on. I have had several throughout the day which is also very unusual for me. I seldom get them. I don't know if it is because the temps are so low and the boiler is running so often but I am getting them now. It could be the draft is messed up as we have lots of wind today as well. Just thought I would put that out there. Ken


The only time I ever experienced puffs with the blower on (in addition to when it cut off) was after I oiled my coal. And I had them back to back just as you have described. I'm not convinced that Coal Guns like oiled coal.


I have been running this coal which is oiled for 1.5 years now first time this has happened. Maybe they don't and this batch had a little more oil in it? Don't know.
NWBuilder
 
Stoker Coal Boiler: Ahs 130
Coal Size/Type: Burning Pea anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Thu Jan 02, 2014 8:34 pm

NWBuilder wrote:I have been running this coal which is oiled for 1.5 years now first time this has happened. Maybe they don't and this batch had a little more oil in it? Don't know.


Or perhaps your current batch of coal has a higher level of volatiles plus the same amount of oil? Coal Guns don't take well to volatiles, and adding oil is similar to adding volatiles. The two together make bad juju. What brand of coal is it? Pea or buck?
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Stockton Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Coalgun- Puff backs & Explosions

PostBy: NWBuilder On: Thu Jan 02, 2014 8:50 pm

I am burning Kimmel pea size coal
NWBuilder
 
Stoker Coal Boiler: Ahs 130
Coal Size/Type: Burning Pea anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: Rob R. On: Thu Jan 02, 2014 8:53 pm

Kimmel's coal tends to have a higher volatile content than coal from locations farther East. Admit a little more air over the fire and it should be fine.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Thu Jan 02, 2014 8:59 pm

Try opening up the ~3/4" port within the flapper cover. That will boost the over the fire air.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Stockton Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Coalgun- Puff backs & Explosions

PostBy: NWBuilder On: Thu Jan 02, 2014 9:06 pm

It's wide open now. Always has been.
NWBuilder
 
Stoker Coal Boiler: Ahs 130
Coal Size/Type: Burning Pea anthracite