Coalgun- Puff backs & Explosions

Re: Coalgun- Puff backs & Explosions

PostBy: Rob R. On: Sun Oct 21, 2012 12:43 pm

This talk about the volatiles is interesting...I have always preferred coal with a high volatile content for its easy starting and ability to hold a fire.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Coal Size/Type: Rice/buck
Other Heating: Dad's 1953 EFM Highboy

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Sun Oct 21, 2012 4:48 pm

Rob R. wrote:This talk about the volatiles is interesting...I have always preferred coal with a high volatile content for its easy starting and ability to hold a fire.


Rob, when you burned Lehigh, did it cause any problems due to its low volatility?
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: Coalgun- Puff backs & Explosions

PostBy: Rob R. On: Sun Oct 21, 2012 5:00 pm

I didn't have any problems with it, but I only burned it in hand-fired equipment. I do remember that it was a little more sensitive to the "rules" of starting and maintaining an anthracite fire in a hand-fed unit. i.e. the coal bed must be 6" deep or more, you must cover the entire grate before starting a fire so no air can bypass the coal, and you must maintain a steady draft at all times.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Coal Size/Type: Rice/buck
Other Heating: Dad's 1953 EFM Highboy

Re: Coalgun- Puff backs & Explosions

PostBy: watkinsdr On: Sun Oct 21, 2012 8:55 pm

I'm convinced this puff-back problem with AHS boilers is really easy to solve. You simply need to ensure there's an open flame to burn volatiles off before they can accumulate. Keeping the fire high enough in the sight tube area resolves this part of the problem; but, due to varying load, weather, etc., it's a pain in the butt to keep changing the PLC "set variable" to keep the fire high in the sight tube area.

Again, the existing AHS design is an open loop control system. Their design really needs to be changed to a closed loop control system; with, a second thermocouple monitoring (and keeping) the fire high in the sight tube area---but not so high you burn up into the storage hopper.

I had puff-backs with my S130---they were simply much smaller.

Gas volatiles occur naturally when when solid fuels transition through their kindling point and combust---this is a completely normal chemical process. No volatiles---no combustion---no heat. It's nonsense to contemplate and compare white ash, red ash, deep mined, strip mined, etc.
watkinsdr
 
Stoker Coal Boiler: AHS S260 Boiler

Re: Coalgun- Puff backs & Explosions

PostBy: pete6500 On: Sat Oct 27, 2012 5:46 pm

I run my ahs130 without a controller only the timer based grate shaker. As I posted some time ago as long as the fire is as high as I dare go there is no bangs.Now last spring after I cleaned out the hopper and all ash I decided to try something different. I bought a dwyer controller and thermocouple with my specs and put the thermocouple in the coal feed tube enclosed in a secondary protective sheath with the tip exposed. I can adjust the amount of travel of the t-couple in the feed tube just before the coal exits into the fire pot. This will give me some idea what kind of temps in that area. I plan to set the control to cooling cycle to turn on grate when temp goes to my high set value. The grate will run until the temp drops as fresh coal enters. I can then determine my diff. setting. This year for the first half of the heating season I'll be using the grate timer and only monitoring the temps with a log at which my fire is optimum with the controller readout. If I'm satisfied I'll switch over to the controller to operate the grate. With this setup it should also keep the fire from climbing into feed tube but still keep the fire high where I want it. watkinsdr mentioned a second t-couple. I 'm sure that would work too. We'll see what happens. Thanks
pete6500
 
Stove/Furnace Model: AHS130

Re: Coalgun- Puff backs & Explosions

PostBy: McGiever On: Sat Oct 27, 2012 7:18 pm

Sounds like a interesting experiment there *pete6500*. :idea:

Let us know what you find out. :!:
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: dchartt On: Sun Oct 28, 2012 10:51 am

wonder if my ahs130 will take me into space and perhaps land me on the moon?
dchartt
 
Stoker Coal Boiler: AHS 130
Hand Fed Coal Stove: Glacier Bay

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Sun Oct 28, 2012 11:08 am

dchartt wrote:wonder if my ahs130 will take me into space and perhaps land me on the moon?


Doubtful. In my experience at least, puffbacks are way overrated. They are more like occasional brief whooshes. And with a bit of adjustment, you can make them all but completely go away.

Your mileage may vary though. Obviously the experiences of some of the forum members have been much more than just a mild whoosh.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: Coalgun- Puff backs & Explosions

PostBy: Rob R. On: Sun Oct 28, 2012 1:01 pm

dchartt wrote:wonder if my ahs130 will take me into space and perhaps land me on the moon?


Doubtful, but your baro might make it into a low orbit.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Coal Size/Type: Rice/buck
Other Heating: Dad's 1953 EFM Highboy

Re: Coalgun- Puff backs & Explosions

PostBy: dchartt On: Mon Oct 29, 2012 2:25 pm

mine did last year
dchartt
 
Stoker Coal Boiler: AHS 130
Hand Fed Coal Stove: Glacier Bay

Re: Coalgun- Puff backs & Explosions

PostBy: MATTHEW D. On: Wed Oct 31, 2012 9:17 pm

Haven't had time to read this thread but my AA130 has been blowing my baro across my garage for the last 6 months. Start happening when I switched from pea to buck? Today the puff back shook the house :!: I took the plug out of the sight hole cover as quoted from Axeman when you switch to buck. I think I need to drill more holes in it???? I'll read more of this thread to try to catch up to what you guys are talking about.................be back soon. MATT
MATTHEW D.
 
Stove/Furnace Make: AXEMAN-ANDERSON & EFM
Stove/Furnace Model: 130 & 900 x 2

Re: Coalgun- Puff backs & Explosions

PostBy: Pacowy On: Wed Oct 31, 2012 11:53 pm

I'm happy not to have any experience in this area, but I'm concerned that what you're describing seems to have the potential to rupture the smokepipe. The joints on universal elbows are often pretty flimsy; a boom that shoots a baro across a garage seems like it could blow apart an elbow. Does that type of damage ever occur?

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: Rob R. On: Thu Nov 01, 2012 8:38 am

Pacowy wrote:I'm happy not to have any experience in this area, but I'm concerned that what you're describing seems to have the potential to rupture the smokepipe. The joints on universal elbows are often pretty flimsy; a boom that shoots a baro across a garage seems like it could blow apart an elbow. Does that type of damage ever occur?

Mike


Finally up and running

Round 2....so far so good
Rob R.
 
Stoker Coal Boiler: EFM DF520
Coal Size/Type: Rice/buck
Other Heating: Dad's 1953 EFM Highboy

Re: Coalgun- Puff backs & Explosions

PostBy: Pacowy On: Thu Nov 01, 2012 9:04 am

Hopefully the people who have these units in their houses are using heavy-duty and secured smokepipe components as described in those threads.

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: chevymatt On: Sat Nov 03, 2012 7:57 am

The links rob posted was my boiler that blew the chimney apart. It was scary when it happened but I learned a lot and hopefully my mishap has helped others. I'm on storm work repairing people's power but when I get home I have a pic from the puff back that shows one of the rings of the flex 90 stuck a 1/4" into a 2x6. It could have killed someone. Be careful everyone
chevymatt
 
Stoker Coal Boiler: AHS S260