What is optimal width for nozzle plate?

[easternbob]

Got all the supplies to build a nozzle for my EKO 25. bought some stainless steel 3/16" thick angle iron, and had some 2" wide ss bar of same thickness lying around.

Was thinking about making the slot 5/8" wide with a couple spacers/vanes to keep things from warping. I've seen people have made them from 1/2" slots to 1" holes.

BUT what is the general consensus on what the optimal width is for the nozzle?

Going to build and install this weekend. Will post some pics when I'm done.

 

[Fred61]

I use a firebrick overlay and I can see the difference in 3/4 inch and 1 inch slots. I actually like the 3/4" better because the flame is smaller but still appears to burn as hot and clean as original. Less idling while charging my storage. Most of the time no idling. Charging time is the same with the smaller flame and no idling as it is with the larger flame adding the boiler cool down time to low limit after high temperature shutdown.

 

[Tennman]

I'd make it like a picture frame with the legs of the angles slipping down into the nozzle opening. So the opening is reduced by 3/16" all around. The 2" leg would then rest on the top surface of the nozzle. 45 deg cuts at the corners and it would drop right in. Using stainless is the right thing. My mild steel nozzle guard corroded away but still saved the nozzle that season. My next guard will use 2" angle as you're doing and welded up as I described above. Check to make sure the angle sides that drop into the nozzle don't cover the air injection ports down in the nozzle throat. I'm assuming your EKO's nozzle has air injection ports like our BioMass. I've changed our nozzle once and have used a guard of some type ever since. Last years ceramic material I tried wasn't so hot. Should have tried fire brick. BTW, I found keeping some layer of ash on top of the guard helps protect it. When I was more diligent to keep the floor of the top chamber clean I ended up with more rapid erosion on our boiler. May just be ours, but keeping a small amount of ash seemed to provide some additional protection. Maybe if I used fire brick this would be unnecessary. Dunno.

 

[easternbob]

Fred61, I've tried the firebrick system but hoping the ss plate will last longer. Have you tried going narrower than 3/4"
Tennman, My cutting and welding skills are limited so I don't think I'll get all fancy with 45's. The angle I purchased is 1.5" legs which I checked will not cover the air injection ports down in the throat. My refractory nozzle is very worn out so I won't have any issues getting the legs to drop down in. Might try the cast in place repair this summer.

 

[Tennman]

Copy. I'll be cutting the angle with a cutoff disk on my right angle grinder. I'll want an angle flange to cover the front and back as well as the sides of the nozzle. I'll use the nozzle protector as a mold tool when I recast/repair the nozzle's ceramic lip.

 

[Fred61]

Fred61, I've tried the firebrick system but hoping the ss plate will last longer. Have you tried going narrower than 3/4"
Tennman, My cutting and welding skills are limited so I don't think I'll get all fancy with 45's. The angle I purchased is 1.5" legs which I checked will not cover the air injection ports down in the throat. My refractory nozzle is very worn out so I won't have any issues getting the legs to drop down in. Might try the cast in place repair this summer.

No, 3/4" is as small as I have gone. Was satisfied with the performance so I stopped there. I leave a good amount of ash in the firebox. I feel that it protects the refractory, helps to "bank" or preserve charcoal for next day's lighting but the main job is to keep the firebrick nozzle in place since it always cracks and needs to be held in place. The powder ash works like mortar. I usually make two of them before the season shelving one as a spare.

 

[Fred61]

My cutting and welding skills are limited so I don't think I'll get all fancy with 45's.

I feel your pain. I've been welding for 55 years and my welds still look like it's my first day on the job.

 

[easternbob]

Got everything welded up over the weekend and have ran the boiler twice, seems to be working great.
I ended up going with a slot that is 3/4" wide. The angle iron is 1.5" each side and 3/16" thick. Hopefully it will last a good long time.
Welding SS was easier than I was thinking, although it does take some getting used to welding at such a low AMP.

 

[Tennman]

Wow... I thot my nozzle was bad!! I'm sure you had a bunch of big clinkers in your lower chamber. You'll be amazed the drop in wood consumption and a return to fine ash in the lower chamber. Stainless and thick, should last quite a while.

 

[huffdawg]

A little late. Here's the nozzle plate opening dimensions on my froling.

1-3/4"x 8"

 

[easternbob]

Weather has been kind of warm so haven't been running the boiler hard but the new SS nozzle plate is working good. This plate replaced the fire brick overlay I was using but as you can see my orig. nozzle is pretty worn so the fire bricks would slope into the hole. The new nozzle spans the gap nicely!

 

[Tennman]

HD, Looks like Froling has replaceable nozzle protectors standard.... is that what I'm seeing?

 

[huffdawg]

HD, Looks like Froling has replaceable nozzle protectors standard.... is that what I'm seeing?

Yup I would say so. they're just sitting in a little bit of a recess. I'm not sure how fast they wear yet but when it does I'll prolly make my own out of ss. like EB. That dunnage in there was just to hold everything still during shipment.

 

[skfire]

Yup I would say so. they're just sitting in a little bit of a recess. I'm not sure how fast they wear yet but when it does I'll prolly make my own out of ss. like EB. That dunnage in there was just to hold everything still during shipment.

Nozzle plates on the Froling 5 years thus far...no issues...thought I may have some warping due to some excessively hot firings(super dry oak/ash fuel 5%-10%..and did not have the "dry fuel setting" selected..great feature..).

 

[Tennman]

Smart design. My first 3/16" thick carbon steel protector warped badly by the end of the season which affected its protection. Those plates look ideal and cheap nozzle protection. If I saw warpage I'd replace it pretty quick after my experience replacing a nozzle. Froling quality on display there, very nice.

 

[Elmer70]

Would placing thin firebrick on top of the metal nozzle plate protect it without a drop in performance?

 

[woodsmaster]

Fred61, I've tried the firebrick system but hoping the ss plate will last longer. Have you tried going narrower than 3/4"
Tennman, My cutting and welding skills are limited so I don't think I'll get all fancy with 45's. The angle I purchased is 1.5" legs which I checked will not cover the air injection ports down in the throat. My refractory nozzle is very worn out so I won't have any issues getting the legs to drop down in. Might try the cast in place repair this summer.

I think any narrower than 3/4 and your going to run into problems with the nozzle getting plugged. When nozzle gets plugged, no gassing going on.