Coalgun- Puff backs & Explosions

You could get a new EFM...or a rehabbed one. Ask Mike Nelson (Pacony) about the performance of a 900, or anyone running one. Keystoker would do the job.....or here's a thought, Axeman Anderson AA 260. Ask ANYONE running one if they are having the same issues as the AHS-130/260's. Another thought is to do some retro work on the feed assembly. Many think the AA is a dinosaur, but quite to the contrary, it is an evolutionary process that was at the top of it's game when they introduced it after WW2.

They ALL work well once you know the tricks, and I learned the hard way just like everyone else, but 570 posts, 17,774 look-sees, are we any further to finding a path out of the woods? That's a lot of horsepower (experience) to not recognize.

whistlenut wrote:They ALL work well once you know the tricks, and I learned the hard way just like everyone else, but 570 posts, 17,774 look-sees, are we any further to finding a path out of the woods? That's a lot of horsepower (experience) to not recognize.

Would you mind sharing what tricks you have learned?

The woodgun is a totally different machine and concept. The woodgun is an air tight boiler and the combustion chamber is full of unburned gasses when it is in the off cycle. There is a timer switch on the boiler to override the aquastat to bring on the combustion fan. This switch must be activated before you open the door to fill the boiler with wood. Failure to do so or get impatient and open it too soon, you get a backdraft.

My dad has had a woodgun for 27 years. I have help fill it for him at times. I got impatient once, opened the door quickly and singed my eyebrows off.

Burning solid fuels have some inherent dangers. You need to have some education on these dangers or you can get hurt.

Larry, yes I will share some of the 'experience' lessons. Steam-up......man can we all relate to being blown on our butts with a hand fed 'puff-back' when you learn to 'crack' the door...on wood or coal rigs. The wood-gun is one hell of an efficient machine, and probably we would all consider that technology if there were no coal to burn.....however coal is available, and it is DIFFERENT from batch to batch. Close enough to be able to keep similar settings.

Draft....the most important word to consider(and the ability to maintain an air source to allow for a draft)
Think of an oil boiler for a second. What technology is now required for a SAFE, CLEAN IGNITION? BEFORE AND AFTER.....THINK......
Control of the air is essential, and velocity of that air. Are coal gasses volatile ? If you have to ask, go to the outhouse, you are too dumb to go any further...........
Familiar with LEL (lower explosive Limit?) and the % required to make the situation a newspaper headline? How about UEL (upper explosive limit)?
Knowing how to operate within these acceptable parameters constantly, is the key to success.

When lighting a charcoal fire, do you soak the brickettes (if they are not already done), or do you just squirt from the lighter fluid container....and toss a book of lit matches in the general direction?????? Can you see where this is going.......????????

Don't trouble your complicated mind right now...just think about it. ...and yes, I have burned a beard, eyebrows, arms, and been knocked on my arse more than once......and I would gladly trade those experiences for less scars, less broken bones, less cuts and less burns, but that can't be altered. The hand-fed guys are tough bastards....simply because they LOVE livin' on the WILD SIDE! (had to get a dig for Freetown Fred---You da man, Fred!!!)

I went from the Itasca 415 direct to an AA 130 and a 260. Steep learning curve, but back then I had the muscles to hang on....now I prefer a quieter presence. The scars remain, the fractures are healed, and the surgeries have been successful, most mental functions are OK, but even that has been questioned many times here on the forum.......

Freddy has the cure...and it could be more universal in a kit......it all costs money.
There is NO trajectory research required, no appointed panel, no fearless leader to fly around the world fact checking.....some bright folks who have the power to think.......

I tried with Ben, no response. I've burned in the sons of b****es for over 43 years, over 2300 tons of PA Gold, If I didn't learn anything, hell I could be President!!! Hawaii is sure warmer than 03301!!!
Perhaps they need a new pet elephant WITH LARGER EARS, to hear the howls in the night........'like talking to wolves'......

I got a call from Darren at AHS today in response to my email sent yesterday. We discussed my idea that puff-backs occur for a brief period of time after loading large amounts of cold coal into the hopper, and that loading smaller loads of coal more frequently might be of benefit. I'm not sure I convinced Darren of anything here. Darren then instructed me to go to an SV of 100 degrees, which I did. I then told Darren about the NEPACrossroads forum, and invited him to check it out.

A few minutes ago I checked the S130 right after a fan cycle was completed and brightly glowing coals were quite evident in the draft port. This is what I remember for Blaschak last season, so it appears (for now at least) that setting the SV down to 100 degrees for Harmony coal is working.

Actually, since I had the 3 puffs yesterday there have been no more, so I'm convinced they occur right after loading it. If I get puff-backs again after loading the hopper with another round of about 160 lbs. of coal, I will switch to loading it more frequently with less fresh coal per load and see if that helps things. I went back to last years spreadsheet and realized that this is exactly what I was doing with the Blaschak. My loads were mostly in the range of 70-80 lbs. per charge last season, when I was keeping the hopper pretty full at all times.

Freddy wrote:My AHS buddy Charlie found he had fewer puff backs if he kept the hopper near full and added a bag of coal each day, rather than add 5 or 6 bags once a week.

Freddy, I'm with you and your buddy on this one. I think he hit on something there!!!

lsayre wrote:

Freddy wrote:My AHS buddy Charlie found he had fewer puff backs if he kept the hopper near full and added a bag of coal each day, rather than add 5 or 6 bags once a week.

Freddy, I'm with you and your buddy on this one. I think he hit on something there!!!

Well if this is so wouldn't that mean that the AA's are less likely to boom, but in freddys case it seems not.

As with the auger it only feeds a little coal at a time



Eric

Coalfire wrote:Well if this is so wouldn't that mean that the AA's are less likely to boom, but in freddys case it seems not.

As with the auger it only feeds a little coal at a time



Eric

They both feed only as much coal as they burn, so they both have to feed the same amount of coal for the same amount of burn time (for the same degree of ashing). The AA however does not have a load of cold coal sitting right on top of the fire tube.

lsayre wrote:

Coalfire wrote:Well if this is so wouldn't that mean that the AA's are less likely to boom, but in freddys case it seems not.

As with the auger it only feeds a little coal at a time



Eric

They both feed only as much coal as they burn, so they both have to feed the same amount of coal for the same amount of burn time (for the same degree of ashing). The AA however does not have a load of cold coal sitting right on top of the fire tube.

That is what I mean, if it is the amount of coal on top or being loaded at once you would think that the AA would never puff back.

I fill my hopper almost every morning and the puff backs were at several different times of the day with the hopper at levels of 3/4 to full. The last major explosion was with a 3/4 hopper. Unless the hopper isn't sealing right I think the hopper level is not the problem.

Mac

macdabs wrote:Unless the hopper isn't sealing right I think the hopper level is not the problem.

FWIW

If I were having puff backs (none to date that I know of on 3 260s) after lowering sv and/or hysteresis and adjusting port door to open as much as possible and still function properly. I would then look to slow down the ashing/feed rate.

Change sprocket size, replace gear motor or wire in a repeat cycle relay. Of the three options the relay would be the quickest and least expensive on a 260. Would be less than $90.00 and a less than 30 min install, while your at it you could add a $10.00 relay to keep unit from ashing unless fan was on if desired. The 2 relays should fit in the existing electrical enclosure if the 130 box is the same size as on a 260.

My logic is that it seams like the avg ashing cycle for my 260s put more coal on the fire and quicker than necessary. The avg cycle lasts about 15m+-, it takes about 5m+- to cover current fire with a layer of new coal (maybe more or less for a 130?) so I would start with 5m on 5m off and make changes from there to keep the new coal layer thinner.

All this assuming the puff backs are caused from build up and ignition of coal gasses. It’s a bit of a pia but this is what I would try for my next line of attack if all else failed to stop puff backs.

YMMV

rwwsr wrote:FWIW

If I were having puff backs (none to date that I know of on 3 260s) after lowering sv and/or hysteresis and adjusting port door to open as much as possible and still function properly. I would then look to slow down the ashing/feed rate.

Change sprocket size, replace gear motor or wire in a repeat cycle relay. Of the three options the relay would be the quickest and least expensive on a 260. Would be less than $90.00 and a less than 30 min install, while your at it you could add a $10.00 relay to keep unit from ashing unless fan was on if desired. The 2 relays should fit in the existing electrical enclosure if the 130 box is the same size as on a 260.

My logic is that it seams like the avg ashing cycle for my 260s put more coal on the fire and quicker than necessary. The avg cycle lasts about 15m+-, it takes about 5m+- to cover current fire with a layer of new coal (maybe more or less for a 130?) so I would start with 5m on 5m off and make changes from there to keep the new coal layer thinner.

All this assuming the puff backs are caused from build up and ignition of coal gasses. It’s a bit of a pia but this is what I would try for my next line of attack if all else failed to stop puff backs.

YMMV

This is some good advice. I have an unused repeat cycle timer.

Larry, 2 every ten..........................

whistlenut wrote:Larry, 2 every ten..........................

Mine is actually called a TORK EJWT "percentage timer". It has one dial for "percentage of on", and another dial for "time", with time ranging from 30 seconds to 24 hours, and percentage ranging from 0% to 100%, so I assume this would mean setting it to '20% on' and '10 minutes' of time. Does that sound right?

http://www.nsiindustries.com/Repository ... _SHEET.pdf

The wiring already restricts my ash grate motor from running unless the fan is on, and the Dwyer LC temperature control further restricts it so that it runs only when the ash grate temperature falls to 95 degrees, and it shuts off at 100 degrees and above. Would I circumvent the LC and go with having the ash grate motor run as a percentage of fan operating time instead?