Steel/Stainless Steel Nozzle Overlay - Any Updades on Performance?

[Medman]

If you have installed a steel or stainless steel nozzle overlay in your EKO/Biomass or similar gasification boiler, how is it holding up?
Any insights into best size or thickness of plate, and size of holes in plate?

I ordered my new nozzle today for my EKO 25 and I have the fab shop lined up to make my overlay - just wondering if there is any new information on this topic.In the past I have used the cut firebrick as a nozzle overlay but I would like to find a more permanent and less fragile solution.

Thanks,

Ryan

 

[Tennman]

I decided to cut four strips from 5/8" thick fireplace hearth refractory material this year. Holding up pretty well. Easy to cut with a circular saw and masonry blade. The two long side pieces can be flipped after the lip gets dull since the long side of the nozzle sees the most wear. Last year's steel shield was too thin at 3/16" and warped. This was pretty easy. After going to purchase firebrick at a fireplace store, it looked like firebrick would require a lot of cutting, piecing, puzzling. The hearth refractory material cost me about $50, but it's enough material to cut 2-3 shields with a shield looking like it will last at least one season.

BTW, I'm also not being so fastidious about removing ash from the upper chamber floor. I think some ash protects the shield lip some with no impact to gasification.

 

[Medman]

Thanks for the reply. I hadn't seen this type of refractory before. I was looking at 3/8 stainless plate - one plate cut to cover the nozzle, with a slot cut in will be about $60. your solution could be much cheaper.

I can't use the firebrick with my worn nozzle any longer, as there is not enough material left to support the firebrick. Also, the bricks are easily dislodged when stirring coals and loading wood. I have tried a couple of configurations with the same results.

 

[goodwood]

If you have installed a steel or stainless steel nozzle overlay in your EKO/Biomass or similar gasification boiler, how is it holding up?
Any insights into best size or thickness of plate, and size of holes in plate?

I ordered my new nozzle today for my EKO 25 and I have the fab shop lined up to make my overlay - just wondering if there is any new information on this topic.In the past I have used the cut firebrick as a nozzle overlay but I would like to find a more permanent and less fragile solution.

Thanks,

Ryan

i have a 3/8 stainless steel overlay,it has held up fine so far for over a year and a half, i need to replace my nozzle [ biomass60], just been putting it off as long as this still works,the lower part of my nozzle is really starting to deterioate , but i still get get gasification

 

[Tennman]

Looking at how I was making "bars" from this material, it dawned on me I could have maybe have bought 3/8" or 1/2" steel barstock to use as the side shields. As I recall the side strips where about 2.5" wide. If the side shields are close to standard bar stock width I may just go with steel or stainless bar stock next time and just cut to length. The small ends that are the width of the slot can be made from lots of materials and not really critical. What I like about using the two long bars is I can potentially get four sharp nozzle inlet openings by just flipping the bars as needed. I think once I've used up the refractory material, I'll look at using steel barstock. Carbon steel vs. stainless melting points indicate plain old steel should perform about as well as stainless. I could be wrong, but stainless costs 2-3 times carbon so I doubt the stainless will have a 2-3 times longer life to justify the expense. Regardless, This is very inexpensive protection to avoid the miserable nozzle replacement job.

Goodwood, Last season I was emptying lots of large clinkers from the lower chamber. I'd say if you're still getting fine ash in the lower chamber and good gasification output you're good for a while. My ash volume is way down after replacing the nozzle. It broke my heart last year to be throwing away nice sized clinkers.

 

[goodwood]

Looking at how I was making "bars" from this material, it dawned on me I could have maybe have bought 3/8" or 1/2" steel barstock to use as the side shields. As I recall the side strips where about 2.5" wide. If the side shields are close to standard bar stock width I may just go with steel or stainless bar stock next time and just cut to length. The small ends that are the width of the slot can be made from lots of materials and not really critical. What I like about using the two long bars is I can potentially get four sharp nozzle inlet openings by just flipping the bars as needed. I think once I've used up the refractory material, I'll look at using steel barstock. Carbon steel vs. stainless melting points indicate plain old steel should perform about as well as stainless. I could be wrong, but stainless costs 2-3 times carbon so I doubt the stainless will have a 2-3 times longer life to justify the expense. Regardless, This is very inexpensive protection to avoid the miserable nozzle replacement job.

Goodwood, Last season I was emptying lots of large clinkers from the lower chamber. I'd say if you're still getting fine ash in the lower chamber and good gasification output you're good for a while. My ash volume is way down after replacing the nozzle. It broke my heart last year to be throwing away nice sized clinkers.

i was getting a lot of big coals [clinkers] before i got the steel plate, i used to scoop them out of the lower chamber and dump them back up top

 

[DaveBP]

I'm not sure "melting" is the issue with a steel overlay.

Iron will burn at a high enough temperature and oxygen supply.
I don't know what alloy steel wool is but it will burn. Kinda pretty in a dark room. (Don't ask). And once you get a cut going in steel plate with an oxy-acetylene torch you can shut off the acetylene and keep cutting with oxygen alone (but not as fast).

But you're right. Having a plate and nozzle-cut fabbed out of stainless will cost a lot more. Somebody needs to try it both ways and report in.

 

[t4driller]

If you have installed a steel or stainless steel nozzle overlay in your EKO/Biomass or similar gasification boiler, how is it holding up?
Any insights into best size or thickness of plate, and size of holes in plate?

I ordered my new nozzle today for my EKO 25 and I have the fab shop lined up to make my overlay - just wondering if there is any new information on this topic.In the past I have used the cut firebrick as a nozzle overlay but I would like to find a more permanent and less fragile solution.

Thanks,

Ryan

This is my first year for running my eko 25. I made a nozzle cover out of 1/4 inch stainless and drilled 6 one inch holes in it. So far it looks like the day I made it and I get very little coals that fall down and great gasufication. I read a couple people on here made it the same way with great success, that's why I made mine. I think jtwall made a you tube video of one. If your not to far from south west pa I would have no problem making you one and shipping it to you.

 

[Medman]

Thanks for the offer, t4driller. I can get the 3/8" x 4" stainless barstock from the fab shop for $1.50 per inch of length, so I'm looking at less than $30 for the material and about $20 in labor to cut in a slot.

Melting is definitely not the issue, oxidation is. Stainless should, in theory, withstand the combination of temperature/airflow and moisture content of the gas stream better than carbon steel.

 

[Tennman]

I think your right Med about it being corrosion. It's interesting I've read here of boilers with cast iron nozzle grates. Not sure why cast iron would be better than carbon steel other than casting is an easy way to produce a complex part. Just looked up 304 stainless and it's about 2x of carbon so probably worth the expense.

 

[Eric Johnson]

T4--why did you decide to go with holes instead of a slot? I'm assuming it was easier to do that way, and it looks like it would work just as well--as you say it does.

Seems like a really nice custom upgrade. My 60 has two nozzles, so I would probably try to get a one-piece unit made that stretches the length of the firebox. Do you think a piece of ss that big would warp?

 

[t4driller]

There was a thread awhile back about holes versus a slot and they said holes worked better for keeping the coals in the top chamber. As far as trying to put a plate across both nozzles, I would make two separate plates. I would think it would warp if one nozzle had good gasification and the other one wasn't going as good. There would be different temperature I would think. I have the 25 so I'm not sure how they run. The only problem I have with the homes is when I'm starting a fire if the holes are covered with coles it won't let enough air in to get the fire going then it gets a big puff of smoke and flames when air finally gets through. So I have just been making sure the holes are not blocked when I start a fire.

 

[easternbob]

tennman,
How wide did you make you slot?

 

[Tennman]

About an 1/8" smaller per side. I wanted the nozzle lip to be outside the most abrasive, high energy flow. I couldn't see any impact of the reduction in nozzle area.

BTW all.... My ceramic fireplace place protector worked up to about 2 weeks ago when it crumbled. My fireplace protector was made from 5/8" thick ceramic so thickness has no impact to the combustion process. But thickness is your friend to keep the protector from warping.

From my experiment, I'm going with SS next time. What I'm going to do next time is make it from 1/2" x 2" or 3" wide SS flat bar. It's not necessary to cover the WHOLE ceramic floor, just protect the nozzle's edge. I like JTWALL's idea of using some thin flat bar welded to the inside lip of the protector which does two things: 1) protects that nozzle lip and 2) keeps the protector located. Again, there is no benefit in having the protector cover the whole bottom of the upper chamber, course you can.... I just left an ash layer the thickness of my protector all around on the upper chamber floor. Worked fine. That's when it dawned on me metal thickness is your friend and you don't need to cover the whole floor with metal, just around the opening. I like JT's design, except I'd use thick flat bar and cover less area in the bottom of the chamber. His idea of stainless sheet down into the nozzle is great for the two reasons sited above. Regardless..... using some type of protection does not affect performance and will save a bunch of grief. I have no experience using holes.