American Rebuild

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cbrew
Posts: 2684
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

American Rebuild

Post by cbrew » Mon Jan 15, 2018 9:54 am

Morning all,
Well after a couple years off, the Allen American is being called back into service.
in order to do that, she needs her boiler back.
after the chassis was over hauled. new links and blocks bell crank arms and a few other pieces. the ole girl is running better than she ever has.
During this rebuild I decided I was going to add at least one pilot burner.
Well as I was inspecting the propane burner assembly I noticed grit under some of the burner caps.
So I decided to pull the burners off the manifold and I was surprised on what I found.
Needless to say, After 12 years of service, there was a fair amount of crud inside the manifold.
After blowing the manifold out, I decided to cut off the center rear two burners to separate them from the main manifold and to also get a look inside.
The inside seemed fine. Just bit of surface rust. So I proceeded with my plan to weld in a plug, and input port. Fabbed up a proper arch for the burner design
so now to the question for the class.
With the arch, I am debating on the need for the baffle plates.
With the arch and in the intent to add stainless tube inserts, I am leaning on not.

also, does anyone know of a good coating for the inside of the manifold.

Input?
Thanks
Attachments
IMG_20180113_124752.jpg
as found
IMG_20180113_130044.jpg
pile of crud
IMG_20180114_133958.jpg
Fabbed up
IMG_20180114_133732.jpg
Installed
If it is not live steam. its not worth it.

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ChuckHackett-844
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Location: Tampa, Florida

Re: American Rebuild

Post by ChuckHackett-844 » Mon Jan 15, 2018 12:21 pm

I can't think of a coating for the inside of the manifold that would stand up to the heat exposure. Slight rust shouldn't be a problem as the gas velocity is very low and even if some comes off it won't get carried far.

Looks like your burner is a bit high - in my mind you want the bottom of the flame just above the bottom of the water leg (3/8" ?) to get the best exposure of the water legs to the flame. (but clearances may prevent this). The burner in my Northern is a "furnace" type (tubes w/holes) sitting at the bottom of the water legs.

Also, you would probably be well served to block off about half of that open air gap at the bottom of the burner. You want the least secondary air possible that still supports full fire. Anything above that and all you're doing is drawing (cool) air through the boiler and out the stack. A coal burner generates more heat when working hard up hill - a propane burner looses efficiency working hard uphill (unless something like a damper/air slats is installed) because the stack is (normally) drawing too much air through the firebox under heavy load.

The arch in my Northern comes out from the rear flue sheet about 1" then up at about a 30 degree from vertical to within about an inch of the crown sheet and horizontal back to within about 3" of the rear of the firebox. (my firebox is about 12" x 18"). The theory is to provide as long a gas path as possible because propane is a slow burning fuel and is still undergoing combustion for awhile after the 'glow' is gone. This arrangement also exposes as much of the firebox (where most of the heat transfer happens) as possible to the flame - yes, the crown is covered, but you can't have everything (or so people tell me :-) ).
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
"By the work, One knows the workman"

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cbrew
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Location: Vancouver Wa

Re: American Rebuild

Post by cbrew » Mon Jan 15, 2018 12:57 pm

ChuckHackett-844 wrote:
Mon Jan 15, 2018 12:21 pm
I can't think of a coating for the inside of the manifold that would stand up to the heat exposure. Slight rust shouldn't be a problem as the gas velocity is very low and even if some comes off it won't get carried far.
I figured that, currently i am thinking maybe blowing some fuel oil in when i winterize to give the tube a coating for the cold winter air. but it did take 12 years to get to this point. In one of the pictures, you can see that the crud did get past the mixer and settled on the inner ridge.
ChuckHackett-844 wrote:
Mon Jan 15, 2018 12:21 pm
Looks like your burner is a bit high - in my mind you want the bottom of the flame just above the bottom of the water leg (3/8" ?) to get the best exposure of the water legs to the flame. (but clearances may prevent this). The burner in my Northern is a "furnace" type (tubes w/holes) sitting at the bottom of the water legs.

Also, you would probably be well served to block off about half of that open air gap at the bottom of the burner. You want the least secondary air possible that still supports full fire. Anything above that and all you're doing is drawing (cool) air through the boiler and out the stack. A coal burner generates more heat when working hard up hill - a propane burner looses efficiency working hard uphill (unless something like a damper/air slats is installed) because the stack is (normally) drawing too much air through the firebox under heavy load.
The burners sit where the primary air is below the mud ring so they can get cool fresh air. the baffle plate sits between the primary air intake and the bottom of the "buds". just about even with the bottom of the mud ring. its always worked good. but she tends to howl when drafting hard and the only way to quite it down is to crack the firebox door.
now this issue may go away with the door i am working on with a damper.
ChuckHackett-844 wrote:
Mon Jan 15, 2018 12:21 pm

The arch in my Northern comes out from the rear flue sheet about 1" then up at about a 30 degree from vertical to within about an inch of the crown sheet and horizontal back to within about 3" of the rear of the firebox. (my firebox is about 12" x 18"). The theory is to provide as long a gas path as possible because propane is a slow burning fuel and is still undergoing combustion for awhile after the 'glow' is gone. This arrangement also exposes as much of the firebox (where most of the heat transfer happens) as possible to the flame - yes, the crown is covered, but you can't have everything (or so people tell me :-) ).
the fire box is 6 inches deep, 3 inches from the bottom of the mud ring to the lower row of tubes. the arch is setup to run vertical for 2.5 inches. and they angles out to clear the lower tubes and continues to swing back as it raises. making sure to leave enough area to support the air flow. when i first converted 12 years ago, I tried the arch i had for the oil firing pan and it was way too low and would stare off the front rows of burners so i had to remove it. while the boiler is off i am trying this. based on your info, maybe i should continue to use the baffle plate. maybe open up the holes a little more.
OR
move forward with the tubulars.. hmmm
more thinking while at the office this week
If it is not live steam. its not worth it.

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cbrew
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Re: American Rebuild

Post by cbrew » Mon Jan 15, 2018 1:13 pm

i found a picture of the baffle plate for reference
Attachments
4257_112955993184_6670315_n.jpg
If it is not live steam. its not worth it.

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ChuckHackett-844
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Location: Tampa, Florida

Re: American Rebuild

Post by ChuckHackett-844 » Mon Jan 15, 2018 2:05 pm

Ah, ok. Not sure how you would reduce the howling ... maybe keep the same open sq inches but relocate it - I assume this plate does not seal up against the water legs .. maybe reduce that gap and drill holes between burners to equal to the area you eliminated (assuming the current open area is working for you). This might re-orientate the flow enough to eliminate the resonance ...
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
"By the work, One knows the workman"

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cbrew
Posts: 2684
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: American Rebuild

Post by cbrew » Mon Jan 15, 2018 3:06 pm

its hard to say, when the boiler was on the american before, i didn't have the howling issue. but i did have it when it served on the ten wheeler chassis.
i had concluded it may have been related to a tighter seal on the front end (smoke box ,etc). which if that was the cause, will still be the case going forward. the baffle does not seal uptight around the mud ring.

i am thinking of opening up the holes a little, the dampened fire door assembly. this maybe manageable.
the plus, with the large holes, it will make it easy to pull the baffle plates out after reassembly.
If it is not live steam. its not worth it.

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