Questions about the ceramic shield

Questions about the ceramic shield

PostBy: LsFarm On: Sun Aug 26, 2007 2:43 pm

Hello Eric, I have an old Axeman Anderson 260M boiler I'm refurbing to put into operation this winter. I am in the process of rebuilding the 1.5" raised lip that the end plate/fan shield/mount is gasketed to.

On my boiler the cast iron end plate has no shielding from the hot gasses and fly ash from the coal fire, and the unprotected inside surface of the mounting lip has erroded pretty badly from the blast of heat and ash.

Since I'm working on it in a very easy and accessable way right now, I'm thinking of upgrading this plate to the AHS ceramic shield and end plate. I can make a new end plate to fit anything, and new mounting tabs/system etc.

I spoke with forum member Yanche, and from his description of the end plate and ceramic shield on his AHS S130, I might be able to change my boiler to use your ceramic shield from an AHS S260, if the dimensions are similar. On the AA boiler, there are bolts used to mount the end plate, it is sefl-centering in the opening due to the inner lip on the plate fitting inside the boiler's lip. I would have to install mounting studs to support the AHS ceramic shield and an end plate.

The raised lip outside diameter on my boiler is roughly 15.5", but I can use as small as 14.75" up to 16" if needed, I would just adapt the mounting studs to fit the 'ears' on the ceramic shield.

Eric could you let me know the dimensions of your ceramic shield for your S260 boiler?? I'll then be able to tell if I can make this work. Also, the price of the shield would be appreciated. Either by post here or PM would be fine.

I have to believe that the ceramic shield would add a measurable increase in efficiency to the boiler. Yanche said the paint hasn't even bubbled on the steel plate over the ceramic shield on his S130, so the ceramic is deflecting and reflecting a significant amount of heat back into the heat exchanger.

On the AA boiler end plate there is a series of bumps for heat radiation on the outside of the plate, I'm assuming this is to keep the plate from getting too hot, It has to be near or at cherry-red after 15-20 minutes of fan operation.

Thanks Eric, Greg Long

LsFarm@earthlink.net
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LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: LsFarm On: Tue Aug 28, 2007 11:38 am

I called AHS to find some answers....

I'm going to answer my own questions here, just incase some folks are interested in what I found out.

First, Eric has gone back to school, so other [very busy] folks at AHS will try to support this AHS info forum. The responce time will be slow, this is their busy season.

I called AHS and spoke with Darren. He described the AHS ceramic end plate for me..

First the end of the boiler has a gasket recess around the boiler lip to hold a rope seal/gasket. Tha AxemanAnderson has a rope gasket retained on the cover plate.

The AHS end plate is a sandwich. There is a 10 gauge steel plate that forms the end of the heat exchanger, then a layer of ceramic high-temp insulation, then a 1/4" thick cover plate that the fan motor is bolted to, if the optional belt drive fan is not purchased.

I was assuming that the ceramic surface was a hard [harder than steel] surface like a ceramic floor tile, and this surface faced the blow-torch of the fan-forced flame and fly ash in the heat exchanger. But the ceramic is a fairly fragile fiber-board that must be protected. AHS is using regular carbon steel to face the blow-torch in the heat exchanger. AA uses a cast iron plate to face the fire. So I see no advantage from a wear standpoint.

So the only advantage to converting to the AHS insulated sandwich would be to reduce heat losses to the boiler room. I'm thinking that AHS designed the insulated sandwich so that the direct mount blower fan motor would not get too hot from the boiler's heat.

So I'm going to stay with my AA cast end plate, the inside surface is in good shape, and the rope gasket seal surfaces are refurbished for use. I'll probably put a layer of fiberglass over the cast iron plate, and put a protective steel plate over the insulation, this will come close to simulating the AHS sandwich without as much reconstruction of the boiler mounting setup.

I'll post photos as I work through the job.

Greg L

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LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

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