Cast Iron Nozzle for EKO?

[Eric Johnson]

I was at Lowe's yesterday buying an angle cutter and diamond blade to trim down my new refractory nozzles (what a pain in the tookus!). Anyway, I mentioned what I was doing to the guy manning the tool department and it turns out he has an EKO 60 as well, and recently replaced the nozzles. According to him, he got cast iron nozzles from Mark at AHONA, and says they work well.

If I hadn't just handed Zenon $200 for nozzles that required extensive modification and expense to make them work, I would have spent the afternoon driving down to Burlington Flats for a set of those cast iron slots. Anybody know anything about that?

Got 'em to fit eventually, but not before basically shaving down all four sides of each one. Trimming down the tops alone didn't work. Boiler works nice, now. I think I got a big gain in efficiency, though it's hard to tell with this relatively warm weather.

 

[velvetfoot]

When I was shopping for boilers, Mark showed me the ones for the Vigas. That's all I know.
You guys need some kind of space-age material that doesn't erode.

 

[Eric Johnson]

They ought to be as durable as run of the mill cast iron grates for a wood or coal stove, I'd think. Those last a good long time. How about a cast iron nozzle body with easily-replaced drop-in ceramic inserts to form the business end of the nozzle? Replace them annually.

 

[cityboy172]

I'm interested. Mine are just patched for the time being.

 

[BoiledOver]

Unless I have missed the one particular thread concerning this issue, there has not been a definitive long term solution. Is this a correct assumption? It is considered a wear item, yes?

There have been several patch, repair, and replace threads. There have been a few "I will try this material" threads. However I have no recollection of any thread that showed a proven material or method that will go beyond a few years.

My research turned up some steel alloys that would probably outlive our stove and us too. Unfortunately those materials are far beyond cost effective. There are some "moderately" priced stainless steels that could withstand the temps and corrosive environment of these fireboxes. Moderately meaning if proven to go 20 years I would consider its cost as acceptable. However, if 8 years was its lifespan, that would be a no go.

If anyone has a proven material or method, please feel free to share this information.

 

[Eric Johnson]

Getting back to the cast iron grate similarity--both exist with a bed of hot coals sitting on them, and both experience airflow across the surface--HOWEVER--with a downdraft gasifier, the hot wood gas passes down through the nozzle. In the case of most cast iron grates, cooler combustion air passes up through the grates and into the firebox and they're never exposed to potentially corrosive wood gas. So, that may be an important distinction determining the lifespan of the exposed material.

I'm still pretty enamored with my idea of having a cast iron holder for ceramic inserts that drop in to form the nozzle slot. It would be a relatively small replacement part (the ceramic) and as long as the cast iron didn't warp or otherwise get deformed, replacement should be a lot easier than digging the big ceramic nozzles out and trying to make the replacements fit. I think you'd see a nice efficiency gain over time if they were replaced every year or two.

As to special materials, I seem to recall, back in the day, when nofossil tried a variety of different alternatives to the u-shaped blocks in the secondary combustion chamber, and wound up with a bunch of very expensive, melted material. My blocks, BTW, are still fine after 8 years of service. One has a visible crack, but it's still together. The other two look cherry. I think that's because I never move them.

 

[BoiledOver]

I'm still pretty enamored with my idea of having a cast iron holder for ceramic inserts that drop in to form the nozzle slot. It would be a relatively small replacement part (the ceramic) and as long as the cast iron didn't warp or otherwise get deformed, replacement should be a lot easier than digging the big ceramic nozzles out and trying to make the replacements fit. I think you'd see a nice efficiency gain over time if they were replaced every year or two.

I agree Eric. Or, maybe just the cast iron piece as the replaceable nozzle. A twenty dollar piece of cast iron easily replaced every two years would not offend me.

 

[Fred61]

All the talk here hasn't made me run out and try the ideas presented. As Eric said. the places where cast iron grates are used have colder combustion air flowing up through the grate. They do fail prematurely in that application if the operator is negligent in removing ashes from below the fire. I've even seen fireplace grates literally collapse when ashes were allowed to build up below the fire. Most common, affordable metals can't take the heat!